Succulents

Among the wide range of sizes, shapes, and colors, there is an easy-care succulent suitable for any Sonoma County garden. Succulents are well adapted to Northern California's dry and mild Mediterranean climate. By storing water in their thickened leaves, stems, or roots, they are able to survive arid conditions in containers or in the ground.

Success growing succulents begins with selecting the right one for the microclimates in your garden. Most flourish in full sun and warmth while others prefer cooler sites in partial shade. Some do not tolerate cold temperatures while others endure freezing conditions. A vast number of succulents remain compact and quite small while others develop large leaves, height, and shrubby forms. It can be rather daunting to choose among the dozens of varieties and types of succulents. Some of the stars for Sonoma County gardens are listed here.

Click on each link for plant details.

Aeonium Agave Aloe Cactus Cotyledon Crassula

Dasylirion Dudleya Echeveria Euphorbia Haworthia Kalanchoe

Sedum Sempervivum Senecio Yucca Other succulents

Foliage

Fleshy, succulent leaves—soft or hard, rough or waxy, smooth or spined—require little care as they contribute splashes of color and dramatic forms wherever planted. Selections are often made for variegated foliage, toothed margins, and dense rosettes, as well as for size and striking hues.

• Leaf color is often more vibrant in bright sun than in shaded sites.
• Foliage may shrivel somewhat in extended drought but will revive with moisture. In the absence of rain, irrigation maintains plump leaves.
• Leaf succulents such as Echeveria, Aeonium, and Sempervivum store water in fleshy foliage usually arranged in a rosette.
• Stem succulents, such as many Kalanchoe, Crassula ovata (jade plant), and cacti often grow taller than leaf succulents and store water in thick, fleshy stems. Many lack true leaves or have very small or hairy leaves that protect against water loss.
• Spines and thorns are specialized leaves; cacti have stems that may expand to hold water.
• Most succulents experience a dormant period during hot, dry summer months when growth slows, but some types are dormant in winter. Stored energy produces flowers when growth resumes.

Flowers

Most succulents produce flowers and seeds, but flowering may be delayed for many years and can be quite varied, depending on the species.

• Some blossoms are small and insignificant; others are produced in clusters; while still others are large, singular, and showy.
• The most common blossom colors are yellow, orange, red, pink, or white.
• Flowers may be fragrant or lack scent, many lasting for weeks, others for only days.
• Deadheadinging spent blooms prolongs the flowering period.
• Monocarpic plants flower and produce seeds only once in their lifetime, after which they die. They often live for many years, building up energy reserves before producing a large and spectacular flowering event. Many produce offsets or pups before dying. Examples are Aeonium, Agave, Sempervivum, as well as some

Planting in the Ground

Succulents are easy to grow but require careful planting practices to ensure they thrive. Selecting the right site for soil and drainage and the right site for height, spread, and sun exposure are all keys to success.

• High moisture content, insignificant leaf litter, and low, if any, flammable oils make succulents a good choice for fire resilient landscapes.
• Well-draining soil is critical. Drainage is fastest with the addition of coarse sand, perlite, pumice, or small lava rock. Little organic matter is needed since it holds water that may damage succulent roots.
• Rock gardens, tufa troughs, and containers are common planting sites, although a carefully amended area in planting beds is preferred by many gardeners.
• Roots must never be exposed to standing water. Planting on a raised mound or on a slope ensures excellent drainage. Avoid planting succulents sensitive to frost in low-lying areas.
• Bright, indirect light is best for most species. Many tolerate full sun, but not blazing heat, preferring exposure to morning or very late afternoon sun. At least 6 hours of direct sunlight per day is needed for flowering and general vigor.
• Too much sun can have a negative effect on evergreen, succulent leaves. Prolonged exposure to intense sunlight can cause the leaves to sunburn, resulting in discoloration, bleaching, or even death of leaves.
• The best time to plant succulents is spring or fall when weather is mild. This allows time for new plants to establish themselves before summer heat or winter cold.
• Prepare a planting area at least twice as wide as the root spread. Wide-spreading and shallow roots take advantage of moisture from dew and light rains. Shallow root systems make transplanting easy.
• Position new plants with the crown—the base of the plant where leaves emerge—just above the soil line with roots fully covered.
• Space small succulents about 4 in. apart and larger ones at least 6-12 in. apart.
• Little or no water is needed while plants are dormant and not actively growing in winter or summer, depending on the species. Inactive plants prefer warm, dry conditions.
• Apply water only when soil is completely dry at least 1 in. below the surface. Probe the soil to ensure that moisture reaches roots.
• Little or no fertilizer is needed. A light dose of a balanced, water-soluble organic product may be applied during the growing season.

Planting in Containers

• When purchasing succulents, check the label or consult a garden expert to learn specific water, light, and soil requirements for each species.
• Use a commercial cactus or succulent potting mix or make your own by mixing equal parts of potting soil, coarse sand, perlite, and pumice or small lava rock.
• Choose a container with drainage holes at the bottom to prevent standing water. A container with a diameter of at least 4 in. is suitable for most small succulents; larger ones benefit from a pot at least 6 in. in diameter.
• Gently loosen any tangled roots on nursery plants when potting. Severely rootbound plants can be pruned by cutting ¼-½ in. off the outside of the root ball.
• Space multiple plants evenly in the container, leaving enough room for roots to grow.
• Water thoroughly after planting, then allow soil to dry out before watering again.
• Provide bright, indirect light; most succulents prefer a morning or evening sun exposure.
• Add a layer of mulch—fine gravel, small pebbles, or coarse sand—on top of soil to help retain moisture. Avoid placing rocks in bottoms of pots; it is a myth this improves drainage.

Pests and Diseases

Most diseases are caused by overwatering or incorrect sun exposure. It's best to remove damaged leaves when they appear. Few pests bother succulents. If natural predators are scarce, pests that do appear may be treated easily with an appropriate insecticide or fungicide or often with plain water or soap solution. Consult details in the links below.

• Ants are secondary pests, attracted to the honey-like substance that predatory aphids, mealy, bugs, or scale suck from leaves and stems. Ants themselves are harmless. 
• Aphids can cause damage by sucking sap from leaves and flowers. Treat with a spray mixture of water and insecticidal soap according to manufacturer’s directions. Repeat every few days until controlled. 
• Mealy bugs resemble a white cottony substance on stems, base of leaves, or on leaves. They may be rubbed off, treated with a soap solution, or removed with a small cotton swab dipped in rubbing alcohol. 
• Powdery mildew is recognized by a white powdery substance on leaf surfaces and may cause leaf drop. 
• Scale insects hide under flat or round coverings and leave sticky honeydew similar to damage caused by aphids. 
• Snails and slugs chew holes in leaves and leave a slimy trail as they move from plant to plant and from nighttime hiding spots. 
• Spider mites can be recognized by tiny speckles, fine webbing, and dust on leaves, but insects themselves can only be seen with a 10x hand lens. 

Additional Information

California's Native Succulents (iNaturalist website)

Aeonium

Most of the 30 or so Aeonium species are native to the Canary Islands and north and east Africa. All require little irrigation in dry sites and are favored as easy-care, rock-garden specimen plants in landscapes. They are favored for their architectural shapes, especially in potted gardens indoors and are considered an excellent choice for both experienced and novice gardeners.

• A wide range of growing conditions is possible but well-draining soil and bright, indirect light are preferred.
• Growth is active during the cool season; plants enter a dormant period in summer when soil should remain dry with very little or no water. Apply light irrigation only if leaves shrivel extensively and begin to drop off.
• Handsome, flattened, foliar rosettes occur on different plant forms, from low, dense spreaders to foot high, branched, shrub-like plants up to 3-ft. tall.
• Spatulate or spoon-shaped leaves taper at the base; leaf tops are rounded.
• Nearly invisible tiny teeth line margins on most species. Fine, hair-like marginal fringe is common.
• All tolerate some direct sun and some shade but indirect light is best.
• Intense summer sun may cause leaves to scorch; frost and low winter temperatures may prompt protection in inland locations.
• Most die after 5 or more years when star-shaped flowers in large clusters develop from centers of leafy rosettes.
• Offsets commonly form during active growth, welcomed as new replacement plants.

Aeonium arboreum, called tree aeonium, assumes a shrublike shape up to 3 ft. high and 3-5 ft. wide, smaller in pots. This species now is found on coastal California bluffs and dunes. Sturdy, semi-woody stems support several open branches, each ending in a typical flat, green rosette. Plants with leggy stems may be rejuvenated by cutting off rosettes, allowing stems to dry at the base as they callus, then replanting to replace older plants. Varieties such as ‘Schwartzkopf’ and ‘Black Rose’ have dark purple leaves with deepest color in full sun. Branches that produce showy, yellow summer flower clusters on long stems will die but non-flowering branches do not. Aeonium canariense, Canary Island aeonium, is similar but more lush and shorter stemmed. Soft short hairs give leaves a velvety texture; pinkish tints develop in sunny sites.

Aeonium ‘Cyclops,’ a hybrid of Aeonium arboreum tree aeonium, is similarly tall and branched but bears dark reddish bronze rosettes. A green center with overlapping leaves resembles an eye, reminiscent of a mythical cyclops.

Aeonium x hybridum (syn. Aeonium x floribundum) lends itself to smaller garden areas with its more diminutive 6 in. x 12 in. size. Green foliage is marked with a brown strip down the center of 4-in. rosettes. Aeonium ‘Kiwi’ has light green leaves, pale yellow centers, and red margins. Best in limited sun, it brightens up a dry shady spot in the garden.

Aeonium urbicum, known as dinner plate aeonium, is true to its description with 8-18 in. wide rosettes on 1-3 ft. stems. Glossy, apple green leaves have soft short hairs along edges and are often trimmed with red margins. ‘Salad Bowl’ is only 1-2 ft. tall and grows in clusters up to 4 ft. wide. Aeonium tabuliforme is also dinner-plate size, similar but less than 1 ft. tall.

Agave

Agave is a drought-tolerant genus of nearly 300 species, including many that are cold hardy and well suited to Sonoma County microclimates. Their striking architectural forms enhance low-water gardens, but also may be grown indoors in pots. Planting any naturally large agave in a container restricts growth and makes them easier to handle.

• Native to deserts of North and South America, agaves are tolerant of hot, dry conditions and are often used in xeriscape and rock gardens in groups or as specimen plants.
• They survive a wide range of conditions but prefer well-draining soil and full sun.
• Individuals grow as rosettes with often large, thick, fleshy, and spiky leaves typically equipped with sharp teeth or hair-like projections along margins.
• Sharp spines at leaf tips can be dangerous and cause injury if not handled with care.
• Foliage is pale green to deep blue-green, often variegated with white or yellow stripes, sometimes with pale or reddish margins. Thin, narrow, and hardened foliage is typical on some species.
• Rhizomes spread freely to increase plants; some species are considered invasive in home gardens. Removing rhizomes and small pups helps the parent plant grow larger into impressive specimen plants.
• Nearly all are slow-growing, maturing and flowering after many years when a tall, central spike or stalk forms, topped with a large cluster of yellow or green flowers.
• All are monocarpic species—plants die after flowering. Spent blooms and the mother plant wilt but offsets or pups around the base can be removed and planted to continue growth or be left in place to create a clumping colony.
• Some species are used for medicinal purposes and for producing a nectar used as a natural sweetener; leaves are used for fiber.

Agave americana ‘Blue Glow’ forms rosettes that grow slowly to 2 ft. tall and wide. Bluish green leaves end with a short red tip and are lined with fine teeth along narrow, red and yellow striped margins. Potted indoor plants may never bloom; outdoors, flowering may occur after 10 years. The species Agave americana itself becomes far too large for most home gardens.

Agave attenuata requires some winter protection in cold microclimates but is quite successful as a houseplant where it becomes a work of art. In large containers, pale green flexible leaves develop into a broad rosette up to 4-5 tall and wide.

Agave ‘Cornelius’, also known as Agave ‘Quasimoto’, has wide yellow leaves with a pale green center. It forms an open rosette with an attractive, slightly twisted, architectural habit. Offsets are produced frequently around a parent plant that is rarely larger than 2 ft. high and wide.

Agave filifera is valued for narrow, foot-long, stiff but arching leaves on a stemless rosette. Each leaf bears threadlike filaments along its edges, giving this species the name thread leaf agave.    

Agave medio-picta alba is considered a medium-size century plant, although it never lives for an entire century, usually for 10-12 years. In maturity, it reaches 3-4 ft. high and somewhat wider, sending out underground rhizomes to create offsets. Eye-catching recurved leaves with white centers and grayish green margins lined with sharp teeth have wicked terminal spines. Careful siting is needed to keep the plant a safe distance from foot traffic.

Agave parryi, commonly called mescal, forms a dense, cupped rosette resembling a foot-tall blue artichoke but with a sharp, dark brown terminal spine on each leaf and smaller, dark, marginal teeth. Many offsets are produced, some at a distance from rambling rhizomes.

Agave victoriae-reginae, true to its name, is regal looking. Nearly triangular 6-12 in. dark green leaves with white margins and blunt tips create a highly prized, sculptural form. Flowering is delayed for up to 20 years.

Aloe

Over 400 Aloe species are native to Africa and Madagascar. They may be distinguished from agaves by their softer, gel-filled leaves contrasting agave’s tough, fibrous leaves.

• All aloes form rosettes, ground hugging or on short or elongated stems.
• Fleshy foliage may be long and linear, long or short and wide, pale or dark green, grayish purple, often speckled or with banded markings. Some foliage is nearly boat-shaped.
• Small, sometimes miniscule, teeth line leaf margins.
• Easy care and small-to-medium sizes make aloes popular as potted house plants for both experienced and novice gardeners.
• Aloes are tolerant of a wide range of growing conditions, but fast-draining soil, infrequent watering, and bright, indirect light are best in rock gardens or planting beds.
• Avoid overhead irrigation to prevent water from collecting inside rosettes and leading to root rot.
• Offsets around the base may be removed and replanted or left where they grow to create a colony. New plants may also be started by taking leaf cuttings.
• Aloes flower throughout the year, depending on the species, some sporadically, others limited to spring, summer, or winter and attracting hummingbirds.
• Some aloe species are used for medicinal and cosmetic purposes.
• Note that while aloes are generally considered safe, some contain anthraquinones that can cause severe cramping, vomiting, and diarrhea if ingested in large quantities.

Aloe aristata, commonly called lace aloe, has thick, triangular leaves wide at the bottom, tapering to a thread-like point at tips. Tight rosettes, 8 in. high and wide, pup readily at the base creating many offsets as a clump forms. Leaves that resemble those of Haworthia are medium green and heavily speckled with attractive small white bumps; small white hairs and teeth form along margins. Clusters of tubular coral flowers appear in summer on thin stalks up to a foot or more tall. Happy in full sun, this species looks better in partial or filtered sunlight.

Aloe arborescens, tree aloe, is one of the tallest species, up to 10 ft. tall and half or more as wide, even larger with great age. Branching structure increases the number of rosettes and coral-red blossoms on stalks that may be 2 ft. tall. Hardiness is not guaranteed; irrigation is not needed in coastal locations. Due to its large size, use it as a background plant in succulent gardens.

Aloe ’Blue Elf’ is a compact hybrid that forms a slowly expanding, dense mound of narrow bluish leaves bearing rosy tints about a foot high after several years. Infrequent flowers are orangish red.

Aloe brevifolia forms a sculptural, tight, narrow, stemless rosette of light green leaves lined with many white teeth along edges. Red tints develop on older leaves. Many offshoots form to create clumps around the 1 ft. high and wide parent plant. Pale scarlet flowers decorate 2 ft. stalks in spring. Rosettes stay close to the ground, making it a nice border plant requiring little water or attention.

Aloe nobilis, golden tooth aloe, spreads wide enough to be used as a groundcover in small areas; in containers, offsets are restricted to tight, mounding clumps. Fleshy green leaves turn orange in bright sun; orange tubular flowers bloom in late spring on 1-ft. stalks. Plants may stay as low as 6 in. or grow as tall as 1 ft.

Aloe plicatilis, an unusual, hardy, tree-like aloe with a potential to reach several feet tall after many years but stays small in containers. Branching woody stems are topped with foot-long, fan-like, flat grayish green leaves that form an eye-catching outline. Orange-red, tubular flowers are carried on stalks in late winter to spring. Give protection to hot sun inland and avoid excess summer irrigation that will cause rot. In its native South African mountainous areas, it receives significant winter rainfall.

Aloe polyphylla, spiral aloe, is aptly named for the spiral, pinwheel arrangement of its thick pale green leaves. The low, rounded pinwheel may spiral either clockwise or counter clockwise; plants grow to about 1 ft. high and 2-3 ft. wide. Give this special species protection from heat and sun and careful placement to enjoy its artful appearance; it is cold hardy. Mature plants bloom in spring.

Aloe striata attracts hummingbirds to its coral-orange flowers rising in clusters on tall stems. Broad grayish green leaves about 6 in. long develop as a rosette, wide at the base, lined with pale to pinkish red on margins.

Aloe variegata bears speckled leaves, giving it the common name partridge-breast aloe. Stemless clumps are usually less than 1 ft. tall. Flowers may be in shades of pink, orange, or red.

Aloe vera, popular for its medicinal effects for burns and insect bites, develops firm, upright, fleshy leaves. The sometimes spotted foliage is filled with mucilaginous gel released when leaves  are broken open. It is widely grown successfully as a houseplant or outdoors protected from intense sun and cold.  

Cactus

More than 1500 species in the Cactaceae family belong to over 100 genera with many names but none are simply “cactus.” A large majority of these species are found in desert regions, mostly in the Americas.

• All have thick, fleshy, modified stems of various shapes—often cylindrical or jointed with vertical ribs—that store water and photosynthesize instead of leaves.
• Spines are modified leaves that protect from predators as well as collect dew that drops to the soil where shallow roots are able to take up moisture.
• Irrigation may be needed to prevent shriveling during long, dry spells.
• Bright light, loose soil, fast drainage, and infrequent water are all needed for long term health away from native sites.
• Purchased cactus potting mix for container plants provides good conditions. Homemade mixes with coarse sand, pumice, perlite, or small lava rock may be added to common potting soil. These amendments added to outdoor planting beds improve drainage.
• Flowering frequency and characteristics vary with species. Some blooms open only at night, others daytime; many flowers are short-lived.

Echinocereus, a California and Mexico native known as hedgehog cactus, has varied forms from thin to globular, thumb-size to 3 ft. tall. The species Echinocereus englemannii with round, heavily ribbed stems grows 4-12 in., occurs singly or in clusters, and is prized for its spring-blooming magenta flowers. Small Echinocereus species are suitable for indoor growing. Flowering is best when this species is kept at 50° in winter.

Echinocactus, a California and Mexico native known as barrel cactus for its round shape, typically produces offsets in clumps after many years. Individuals create extraordinary specimens in rock-filled beds, especially the species Echinocactus grusonii, golden barrel, that reaches 4 ft. high and 2-3 ft. wide with many spine-filled ribs. Some juvenile forms are suitable for indoor growing. This species is the best known and easiest to grow. Others need constant care.

Echinopsis spachiana, one of nearly 100 species of Echinopsis from South America, rises to an impressive 5-7 ft. with many offsets at maturity, usually in clumps with yellow-to-brown spines. In spring, groups of 6 in. white flowers form at tops at night or in daytime but last only a day. Most other species require cold in winter months before flowering.

Opuntia includes over 200 species, many too large for home gardens. Some species form cylindrical joints, but those with flattened, pad-like shapes are most popular and are sometimes known as prickly pear for their presence of spines. Opuntia microdasys, called bunny ears, is fast growing to 2-3 ft. as it develops a rather sculptural form with many-branched spineless pads. 

Opuntia santa-rita, purple prickly pear, forms clumps usually with spines, branching from the base to as much as 6 ft. The reddish purple pads become even more colorful in very dry and cold conditions. Yellow flowers erupt near tops of pads in spring. In containers, plants are smaller. Edges and flat surfaces of all opuntias are covered with tiny, easily detached, hairlike spines called glochids that can be extremely irritating.

Cotyledon

Succulents in the Cotyledon genus native to South Africa are known for thickened, fleshy, often pale, gray-green leaves and shrubby forms with leaves opposite or whorled on stems. Only a few of the dozen or so species have become favorites in home gardens. Freely branching stems root easily, quickly developing low, frost-hardy mounds in nearly any soil. Leaves shrivel when moisture is lacking for long periods but recover quickly with rains or irrigation.

• A thin, powder blue coating on rounded leaves reduces evaporation.
• Older leaves eventually wilt and self-prune, exposing thick stems.
• Bare stems propagate readily in moist soil with roots forming at nodes where older leaves have dropped off.
• Flowers appear variously in late winter to summer.
• Cotyledons are considered poisonous to animals.

Cotyledon orbiculata is called pig’s ear for the round leaf shape, narrowing to a soft point at top. Stems may reach 2-ft. tall although plants often sprawl much lower; growth is slower and more compact in containers. Easy care is a hallmark in sun or part shade in lean or lightly fertilized soil; frosts are tolerated. Rosy tints often appear on foliage. Coral-red, rarely yellow, bell-shaped blossoms dangle on stalks above leaves.

Cotyledon ‘Flavida’,(correctly named Cotyledon orbiculata var. oblonga ‘Flavida’) is a tubular leafed form canned finger aloe.

Cotyledon ‘Macrantha’,correctly named Cotyledon orbiculata var. oblonga ‘Macrantha,’ is similar to the species. Large orange-red flowers in winter are borne on many branched stems with leaves edged in red.

Crassula

Crassula is a genus of nearly 300 species of succulent plants native mostly to South Africa. Gardeners are attracted to the wide variation of plant forms, colors and shapes of fleshy leaves.

• Many species are grown as houseplants, too tender outdoors in frost and winter chill. Some smaller species are grown as low-humidity terrarium plants.
• Many gardeners opt to grow crassulas outdoors in pots and move them indoors during cold weather.
• Attractive in rock gardens in mild climates, crassulas withstand long, dry periods.
• In garden beds in mild microclimates, plants survive longest with infrequent irrigation.
• All have fleshy leaves—needlelike or circular, plump or flat, pointed or rounded—often on stout, branched stems.
• Bright sun brings out yellow, orange, and red hues on leaves; those in shade remain green.
• As plants age, leaves and branches self-prune, allowing sunlight to reach inside.
• Small, star-like, white or pink flowers appear in clusters, sometimes profusely.

Crassula capitella ‘Camp Fire’ has fiery red, fleshy leaves radiating from 6-in. tall stems at right angles in bright, sunny sites; but foliage remains green in shade. White star-shaped flowers are borne in summer-fall.

Crassula muscosa, watchchain plant, produces curious, thin, branched stems 1-1½ ft. tall clothed with tiny, apple green, overlapping leaves that resemble an interlocking chain. Colonies slowly spread in sun or part shade and withstand most winter cold in Sonoma County.

Crassula ovata, known and loved as jade plant, is widely grown as a houseplant due to its need for winter protection. In mild outdoor locations, it eventually reaches tree size after many years. Nearly round leaves with red margins drop from stout stems as plants age. Small, star-shaped white or pale pink flowers at stem tips nearly cover plants in late winter. Newer forms include Crassula ovata ’Hummel’s Sunset,’ golden jade crassula; Crassula ovata ‘Hobbit’ with fluted leaves; and Crassula ovata ‘Gollum’ with nearly tubular foliage.

Crassula perforata, string of buttons, is recognized by a series of square or triangular perforated leaves alternating at right angles on a thin, elongating stem. Fast-growing to a foot or taller, plants may become crowded in a pot. Bright light and full sun promotes denser growth and rose tints on gray-green foliage.

Crassula tetragona, miniature pine plant, has narrow, apple green, cylindrical leaves resembling those on pine trees, but stouter and in pairs opposite on stems. Older leaves fall and expose bare stems that may reach 3-4 ft. and become sparsely branched. Takes full sun or light shade and tolerates some frost, but is often grown indoors. Some plants have naturalized in southern California. White blooms may appear on branch tips after several years.

Dasylirion

Dasylirion is a genus of about 18 succulent plants native to deserts of southwestern United States and Mexico. Striking architectural form and tolerance of hot, dry conditions has led a few Dasylirion species to be featured as specimen plants in xeriscapes and rock gardens.

• Size and shape make these plants unsuitable for small spaces.
• Exquisite, symmetrical clumps of thin, stiff, spiky leaves to 3 ft. long form spherical or fountain-like shapes atop a stout stem that, with age, elongates 3-5 ft. high.
• Leaves are typically green or blue-green, spoon-shaped at the base; most species bear leaves ending with sharp tips and have short, sharp spines along leaf edges.
• Drought-tolerant plants perform easily in a wide range of growing conditions, but prefer dry, well-draining soil and full sun.
• A large taproot allows survival in arid months; growth is faster with summer irrigation.
• It takes many years for plants to mature before producing a 12-ft. or taller flowering spike of small white or greenish flowers, either male or female and borne on separate plants.
• As older leaves die, they continue to cling to the stem, producing a skirt-like appearance.

Dasylirion wheeleri is the species most commonly seen in gardens. Keep plants away from pathways and wear gloves when handling to protect from leaf margins that are sharply serrated and grab onto clothing or skin. As leaves dry out at the bottom of the spherical leafy top, prune them away for a neater appearance. The stout stem may branch at the base after flowering occurs.

Dasylirion longissimum, called Mexican grass tree, lives up to its name. It requires considerable space away from foot traffic despite smooth leaf margins and soft tips. Narrow leaves 3-6 ft. long rise fountainlike at the top of a stout, stiff stem 8-10 ft. tall after  many years as it grows slowly to form a woody trunk. This species adapts to sun or shade, hot or cold temperatures, and nearly any soil as long as it is well drained. A flower spike nearly 10 ft. tall supports a creamy white inflorescence.

Dasylirion texanum, Texas sotol, develops a short trunk in contrast to other species but with similar dark or bluish green leaves emerging from the top and cascading as they age. Leaf margins carry short, sharp spines.  

Dudleya

Nearly 40 Dudleya species are native only to western North America. Common along coastal bluffs, Dudleya occurs on Pacific slopes from southern Oregon to Baja California. At least one species—Dudleya cymosa in Sonoma County—occurs on rocky outcroppings inland.

• Protected by legislation in 2021, plants may not be harvested in California without permits or a landowner’s permission.
• Low-growing perennials, known as live forever, produce offsets close to the parent plant and survive for many years, even decades, with neglect in dry, rocky environments.
• Rosettes have fleshy spoon- or lance-shaped leaves, usually narrow at the base and wider at the top.
• Leaves are coated with a chalky white substance, may be pale or grayish green with tints of reddish pink or purple, depending on the species and amount of sunlight they receive.
• Summer dormancy causes leaves to shrivel, but they plump up with the onset of rains.
• Branching forms spread into colonies with multiple rosettes on elongating stems that may lie horizontally and be used as a small-area groundcover.
• Unbranching forms produce a solitary rosette, excellent as a container plant.
• Clusters of tiny yellow, red, or pink flowers in spring or summer are on short, thin stalks.

Dudleya brittonii, giant chalk dudleya native to southwestern United States and Baja California, has become a choice selection for container growing for its striking grayish white, solitary rosette up to 1½ ft. wide, but it also makes a singular specimen in a rock garden. It needs excellent drainage, best on a slope, to prevent water from collecting inside rosettes and to protect roots in winter. Some protection may be needed in microclimates where freezes occur, as well as protection from high heat and afternoon sun in inland sites. A nearly 2-ft. red flower stalk carries pale yellow or rosy red flowers attractive to hummingbirds in spring.

Dudleya farinosa, sometimes called cliff lettuce, is the only native dudleya along the Sonoma coast. It requires protection from intense sun inland and from cold temperatures. Small, compact tufts of grayish leaves sport yellow flowers in summer.  

Dudleya ‘Frank Reinelt’ develops finger-shaped, silvery blue leaves in a tight rosette, 6-10 in. tall and wide. It is quite at home in a rock garden where it receives excellent drainage.

Dudleya caespitosa, sea lettuce or coast dudleya, is native along or near the coast from San Francisco to Los Angeles. Grayish white rosettes of 20-30 finger-like leaves are highlighted with rose-colored tips; offsets develop to form slowly broadening clumps. Good drainage and infrequent watering are essential. Bright yellow flowers form in summer atop foot-tall stalks.

Dudleya pulverulenta, chalk liveforever, is similar to Dudleya brittonii, but spreads wider with many offsets. It is more frost tolerant than other species but also requires afternoon shade. A California native to chaparral and coastal scrub from San Luis Obispo County and south, it is seen on slopes and rocky areas where it receives good drainage that must be replicated in home gardens. Success is best in part-to-full shade where little to no irrigation is needed. Red flowers on tall stalks appear in spring and summer.

Echeveria

Echeveria is a genus of succulent plants that includes over 150 species, but far fewer are commonly grown. Native to mostly desert regions in the Americas, they are known to gardeners as hen and chicks for the numerous offsets formed around the parent plant.

• One of the easiest and most popular succulents grown in Sonoma County, especially in borders and rock gardens, but also successful as houseplants.
• Well adapted to home growing when planted in well-drained soil and not overwatered.
• Drought conditions are tolerated, but best with light irrigation every few weeks during dry spells. Less frequent irrigation required in cooler microclimates near the coast,
• A few are slow-growing and slow-spreading varieties, but most develop small colonies within a few years, wider colonies as they age.
• Most have small, smooth, fleshy leaves, somewhat spoon-shaped, broader at the base and usually ending in a short point at the tips in shades of green or gray, often with red, orange, purple or pink hues; greener in complete shade.
• Rosettes vary in size somewhat, but most exhibit short leaves in tight rosettes. Collectors search out species with ruffled edges, fuzzy leaves, long, pointed tips, and bluish lavender colors.
• Summer blooms are carried at tops of thin stems rising from between leaves. Urn-or bell-shaped, nodding flowers are often orange but may be pinkish, white, or yellow.
• Some shade is needed in hot inland locations for protection from intense, direct sunlight.  Leaves may burn or become lightly scorched when exposed to hot summer sun.
• Propagated easily from offsets and from leaves carefully removed from stems, allowed to dry at the base, and placed in moist germinating medium. Leggy stems may be cut back and treated in the same manner.

Echeveria agavoides ‘Lipstick’ is a choice stemless selection for growing in pots but is equally attractive in the ground. It is dependably cold hardy, growing 6-12 in. tall and wide and develops red flowers with yellow accents in summer. Thick, rigid, triangular, glossy, apple green leaves are tinted deep red at tips and along upper margins. Small white or brown spots may appear on upper leaves when plants are overexposed to searing sunlight.

Echeveria elegans, Mexican rose or Mexican snowball, is one of the most beautifully hued small succulents with exquisite, silvery green, tight rosettes. It grows only 2-4 in. high, with colonies spreading to nearly 2 ft. Flowers are borne on slender pinkish stalks in the warm season. It absolutely demands infrequent watering and partial shade and can be disfigured by sunburn.

Echeveria ‘Afterglow’ leaves are somewhat wider and flatter in more open rosettes than similar species. Eye-catching, muted purple, pink, and gray leaves are edged in deep pink. Rosettes may reach more than 1 ft. wide; flower stems tend to flop when heavily laden with reddish urn-shaped blossoms. ‘Afterglow’ needs protection from frost in most microclimates. Plants do not survive when overwatered.

Echeveria x imbricata is widely popular for its good looks, easy care, and availability. One of the hardiest of the species, this hen and chicks succulent grows freely in both sun and partial shade, requiring only infrequent summer water. Red and yellow flowers appear reliably in summer.

Euphorbia

Euphorbia is a large and diverse, worldwide genus of over 2000 species that includes every plant type. Not all are succulents, but all release a toxic milky sap that can cause skin irritation.

• Many euphorbias, including succulents, are common in perennial borders while others are used in rock gardens or as container plants.
• One of the most well-known is the potted poinsettia. Some have medicinal uses, while others, such as spotted spurge, are weeds in Sonoma County.
• Foliage on many species has unique shapes, including a large number with distinct resemblances to cacti.
• Showy bracts on all species attract attention as they surround tiny flowers that are mostly small and insignificant, typically green, yellow, or cream-colored.
• Some species develop a swollen bulblike, succulent base (caudex) that supports leaves and blossoms and are prized as container plants.
• All need good drainage in loose soil and bright sun. Summer irrigation keeps plants vibrant.
• Some species cannot tolerate excessively wet winter conditions, but most tolerate frost.
• Loose soil is ideal with minimal amounts of organic matter and infrequent fertilizing in very poor soil and in containers.

Euphorbia characias, Mediterranean spurge, is most often known in gardens as E. c. wulfenii. Large, splashy clusters of bright lime green flowers at tips of 3-4 ft. stems in early spring create a dramatic focal point. When flowering stems fade, prune them to the base to prevent seeds from scattering or they will self-sow prolifically.

Euphorbia horrida, African milk barrel, closely resembles a cactus but can be identified as a euphorbia by greenish yellow blossoms that appear at stem tops in summer. Clumps of erect stems with 10-20, sometimes wavy, ribs may reach 5 ft. tall with age, but remain small for years, particularly in pots. Heavily spined bluish ribs form clumps with offsets at the base.

Euphorbia myrsinites, donkey tail spurge, has become established in some California areas but is native to Asia and Mediterranean areas. This ground-hugging spurge releases large numbers of seeds and self-sows readily if faded flower heads are not removed. Little to no supplemental water may be needed in summer, especially in shaded sites.

Euphorbia resinifera, resin spurge, vertical stems rise cactus-like in multiples from the base with short, yellow spines along green ribs. Side branches form on 4-angled stems that reach up to 1 ft. tall with yellow blossoms on tops. Short, grayish spines are carried on angled ribs.

Euphorbia rigida, gopher plant, branches as it matures with narrow, grayish green leaves that spiral perpendicular to stems, eventually becoming somewhat bushy 2 ft. high and wide. The name is a misnomer for local gardeners since it is not known to deter gophers in Sonoma County. It thrives in nearly any soil in a sunny site but tolerates some shade. Clusters of chartreuse bracts occur at branch tips and produce seeds that may self–sow. Cut back faded blooms to prevent reseeding and to promote fresh branching.

Haworthia

Haworthia is a genus of over 70 dwarf, stemless, succulent plants from South Africa, closely related to the aloe genus.

• Triangular stubby, leaves are wider at the base and taper to a point at tips, sometimes twisting in a group of 3 and marked with patches, lines, or shiny, wart-like bumps.
• Fleshy leaves on some species are dagger-shaped in pale or dark shades of green.

Tight rosettes may be low and stemless or on elongating stems.

• Slow-growing, well-suited to growing in pots.
• Some species have transparent or translucent window-like leaf tips that allow light to reach the inner part of the leaves.
• Popular for growing indoors for their preference for mild temperatures and medium to low light. Give protection from high heat and winter frosts.
• They produce small, white, or green flowers that grow on wiry stalks well above foliage.

Haworthia attenuata grows stemless only 3-4 in. high but develops a flowering stem as much as 1 ft. tall. Chunky leaves, broad at the base, may be slightly curved, rough, and sharply tipped. White, warty bumps, often in horizontal lines decorate leaves. Small clumps form as offshoots develop around the base.

Haworthia coarctata (syn. Haworthiopsis coarctata) has yellowish or dark green leaves curving inwards and covered white bumps or tubercles usually in horizontal lines. Flowers on tall stalks may be removed if they detract from interesting leaves tightly wrapped around stems in layers 6-12 in. high. This species grows best in semi-shade or indoors in containers with good drainage and a gritty soil mix. Soil should stay dry during summer dormancy.

Kalanchoe

Over 100 species of Kalanchoe are native to Madagascar and tropical Africa, but only a few are readily available for home growing in gardens or as houseplants.

• Many species have broad, smooth, fleshy leaves with brown or red markings.
• Bright light promotes flowering but plants must be protected from intense sun when grown outdoors.
• Fuzzy-leaved species are coated with thin, velvety hairs that protect against leaf burn from exposure to sun.
• Easy care and infrequent watering are attractive features, especially for novice gardeners.

Kalanchoe blossfeldiana assumes a bushy form 1-2 ft. high and wide with broad, bright green, slightly leathery, scalloped leaves. Clusters of small red flowers are commonly seen but there are yellow, orange, and coral flowering hybrids. Grow outdoors in the warm season but move indoors in winter.

Kalanchoe luciae, called paddle plant or flapjack for the clam-shell shaped, 5-6 in. leaves, green with a red blush in bright light, 1-2 ft. tall. Plants take several years to bloom with yellow blossoms on a 2-3 ft. stalk above foliage. Hardy in all but the coldest microclimates.

Kalanchoe marnieriana slender stems are freely branching in a foot-high succulent, shrublike tuft that slowly spreads. Small, circular gray-green leaves line soft stems. Dangling purplish red flowers appear at branch tips nearly nonstop. Give protection in cold microclimates; reduce irrigation in summer.

Sedum

Sedum is a large and varied genus of succulent perennials. The estimate of 300-600 species native to the Northern Hemisphere changes frequently as botanists discover differences among them.

• Many sedums are associated with rock gardens and drought tolerance but are also planted in sun-drenched beds with well-drained soil and limited irrigation.
• Sizes, shapes, leaf colors, and flowers differ considerably depending on species.
• Most species are frost hardy grown outdoors but are often selected as indoor container plants for their low maintenance and low-water requirements.
• Propagation from stem cuttings or detached leaves easily produces new plants.
• Low-growing, small-leafed sedums make excellent groundcovers that require only minimal irrigation.

Sedum adolphii (syn. Sedum nussbaumerianum), develops a trailing habit natively on rocky slopes in Mexico. Planted in gardens, stems grow to 1 ft., often branching and bending. As chunky inch-long leaves fall, they produce roots and new plants. Glossy upturned, lime leaves turn orange in bright sun winter or spring with white, star-shaped flowers.

Sedum ‘Autumn Joy,’ correctly known botanically as Hylotelephium ‘Autumn Joy,’ continues to appear in nurseries under several names. Spring growth appears at ground level as round sprouts then rise as 1-2 ft. succulent stems topped with a flat blossom cluster. Pink flowers in spring develop deeper tones before turning bronze to rusty brown and dying back in the winter when stems should be cut to the ground. Bees visit vibrant flowers and birds feed on seed heads in late autumn.

Sedum morganianum ‘Burrito’ is a tender, compact variety most often grown as a houseplant in a hanging basket to display numerous trailing stems with grayish green, overlapping leaves. This somewhat unusual succulent may require a richer soil than most others to look its best. 

Sedum x rubrotinctum, called pork-and-beans or jelly-beans, is similar to the more compact and paler green Sedum pachyphyllum jelly bean plant. Pork-and-beans plant has a more bronze-red color on rounded leaves and assumes a larger, overall size. Outdoors, stems may root as they grow horizontally at ground level.

Sedum spathulifolium, native to the California coast and the Sierra Nevada, grows in tight tufts, spreading mat-like in gardens but tends to sprawl more on rocky slopes. Very small greenish gray leaves with a chalky powder may turn red in full sun. Tiny yellow flowers form at stem tips in summer. Best planted on slopes to prevent damage from accumulating moisture. ‘Cape Blanco’ has powder blue leaves.

Sempervivum

Sempervivum, known as houseleeks or hen and chicks, forms tight rosettes of fleshy leaves pointed at the tips. One of the most cold-hardy succulents with named cultivars numbering in the thousands, they are native to Europe, North Africa, and Asia mountain regions.

• Smooth or fuzzy leaves are narrower and more pointed at tips than similar-looking echeverias. They form tight or open rosettes 2-6 in. high and up to 6 in. wide.
• Offsets in colonies around the parent plant can be separated to form new plants.
• Leaves are arranged in a symmetrical, circular pattern, often covered in fine hairs or a powdery coating that helps retain moisture. Miniscule sharp teeth are found along margins.
• Foliage may be green, red, purple, or a combination of colors.
• Small, star-like flowers bloom in summer in shades of pink, red, yellow, or white.
• After flowering each plant dies, but offsets readily fill in empty spaces. Removing blooms when they first appear may extend life of an individual rosette.
• Considered drought-tolerant, plants shrivel during extended dry periods but revive with rains or irrigation.
• Plants tolerate a wide range of lighting conditions but are best with plenty of sun.
• They must have excellent drainage to withstand wet, cold winters, but are hardy enough to survive even sub-zero temperatures.
• Grow in rock gardens with loose soil, as part of a succulent dish garden, or in pots, or in crevices of rocks.

Sempervivum arachnoideum, cobweb houseleek, is unusual for the fine hairs covering very small, 2-3 in. grayish green rosettes. Tiny individual tufts spread to create mat-like colonies a foot or more wide. These cold-hardy plants thrive best when grown outdoors. Intense heat and overwatering cause severe damage. Pinkish red flowers bloom in summer.

Sempervivum tectorum hybrids may spread up to 2 ft. wide, an attribute that led to a history of being planted on rooftops in Europe and elsewhere. The Latin species name, “tectorum” indicating “roof,” has maintained its interesting history that continues today on eco-driven green roofs.  Numerous hybrids are variable but carry reddish blossoms on tall, thin stems as well as red or brown leaf tips.

Senecio

Over 1000 Senecio species of nearly every plant type grow worldwide. All bloom with white, yellow or purple daisy-like flowers that some gardeners remove to emphasize leaf forms. Succulent species store water in fleshy leaves and survive dry conditions.

• Blue hues and unique leaf shapes lend many gardeners sought-after contrasts to green or burgundy foliage.
• Most Senecio succulents flourish in bright or filtered light.
• Plant in loose, not heavy soil that drains easily and give infrequent watering. Sandy soil is ideal but may require irrigation in summer.
• Stems root readily in moist soil.
• All are toxic to pets and horses when ingested.

Senecio kleiniformis, known as spearhead, grows as a subshrub with succulent, woody, stems, and deeply cut 4-in., blue-green leaves that give off a pungent odor when broken open. Lean, dry soil and filtered sun promote upright growth that tends to flop in rich soil and shade. Plants suffer from overwatering and intense winter cold.

Senecio mandraliscae (syn. Kleinia mandraliscae), blue chalksticks, grows fairly rapidly, producing blue, finger-like, curved leaves 3 in. long on stems interconnected at the base. Stems may stand upright to 1 ft. tall but tend to flop as they spread. Little to no summer irrigation is needed; maintenance is limited to deadheading often undesired white flowers. Senecio vitalis, narrow-leaf chalksticks, are similar but leaves are thinner and often more upright.

Senecio rowleyanus, string of pearls, creates a dramatic display of 1-3 ft.-long, string-like stems carrying round, pea-size, succulent leaves resembling beads. Often displayed in hanging pots but may be planted in the ground where stems trail, rooting as they grow to form mats. Give light shade or indirect light, water infrequently when soil is dry, and protect from winter freezes.

Yucca

Yucca is a genus of nearly 40 species native to deserts and other arid regions of North and South America. Perhaps the most unique and well-known yucca in California is Yucca brevifolia, the Joshua tree, famous for its tree-like presence in the Mojave Desert.

• Yuccas are dynamic specimens among succulents and a valuable foil for extensive hardscape in a dry garden.
• Leaves have sharp, terminal spines; plants must be located away from foot traffic.
• Easy care and drought-tolerance are hallmarks of all species, as well as cold hardiness and showy spring or summer blooms.
• Foliar clumps begin as rosettes. After many years, stems may reach a few to several feet tall, branched or unbranched with rosettes at stem ends.
• Leaves are pale green to deep blue-green, often with yellow, white, or pink variegation in centers or along margins.
• Select for leaf color and overall form—low, stemless structure, tall stems, multiple trunks, height of flowering stalks.
• Plant in full sun in lean, well-draining soil.
• Most species are slow-growing and can take years, even decades, to mature.
• Some become sizeable clumps, producing pups close to the parent plant.
• Offshoots arise from the spread of underground rhizomes.
• An elongated flower cluster clothes the top of 3-10 ft. tall stalks called scapes.
• Blossoms are white or cream-colored and bell-shaped. When blooms fade, cut the entire stalk to its base.

Yucca aliofolia, Spanish bayonet or dagger plant, is native to coastal areas along the Gulf of Mexico. Young plants remain close to the ground in stiff rosettes to 4 ft. wide; leaves terminate with an extremely sharp spine. This species grows slowly but reaches nearly tree size after many years, branched or unbranched with old leaves persisting on the trunk. In summer, a 2-ft. stalk of nodding white, bell-shaped flowers with purple tints rises above foliage.

Yucca baccata, banana yucca, native to desert mountains in Southern California, is named for fruits that somewhat resemble bananas and may be roasted and eaten. Cold-hardy plants may be stemless or as tall as 6 ft. with 2-ft. long leaves.

Yucca filamentosa, Adam’s needle, includes several desirable named varieties such as ‘Bright Edge’ and ‘Color Guard.’  Widely planted for its 2-3 ft. height and 5-ft. width, it is extremely cold hardy, appreciates summer irrigation, and is similar to smaller Yucca flaccida.

Yucca gloriosa ‘Bright Star’, a slow-growing and showy cultivar to 3 ft. tall with soft, curving leaves lined with yellow along margins. Creamy white flowers appear in late summer from showy, pinkish red buds on 3-ft. spikes

Yucca whipplei, Our Lord’s candle, can be seen on road cuts along southern California freeways and coastal area, but it is cold hardy in northern gardens. Rosettes are trunkless with grayish green foliage ending is razor sharp tips. Very tall blossom spikes to 12 ft. or more hold a large blossom cluster; plants die after flowering but produce offsets.

Other Succulents

Gasteria bicolor, one of over a dozen Gasteria species native to South Africa, with fleshy, straplike leaves in rosettes or with fan-shaped leaves on stems that may lie horizontally. Very tender and best grown as a houseplant. Deep green leaves are often marked with pale speckles. Pale, nearly ball-shaped flowers appear on a tall spike.

Graptopetalum paraguayensis has trailing, foot-long stems ending in compact, flat, gray-green rosettes that produce spotted red flowers. Other species may be stemless with dense, star-shaped, tinted rosettes with cream blossoms. Grow in bright, indirect light; cold hardy in winter.

xGraptoveria ‘Fred Ives’ is a hybrid of Graptopetalum paraguayensis and an Echeveria. This hybrid has varying forms but resembles each parent with bronze and pink tinted green leaves. Clumps of rosettes 8x12 in. grow on short stems; reddish orange summer flowers are held on branched stalks.

Delosperma cooperi, a winter-hardy ice plant that appears to be noninvasive, is planted for bright purplish pink aster-like blossoms summer-fall. Ground-hugging to 3 in. high, it spreads vigorously to form a mat-like groundcover over 2 ft. wide with dark green, cylindrical leaves and stems. Delosperma nubigenum is similar but with bright yellow flowers and similar foliage that develops reddish tints autumn-winter. Both are commonly planted in rocky areas and on slopes.

Drosanthemum floribundum, rosea ice plant—one of several South African succulents so named for the impression of icy dots on its reflective leaf surfaces. Spreading roots are used to stabilize slopes while trailing stems decorate rock walls. Fringed, bright pink, aster-like pink flowers with yellow centers cover 6-in. plants in spring. This plant has naturalized along the California coast. Does best with little or no summer irrigation.

Calandrinia spectabilis grows as a somewhat rambling, sun-loving, easy-care perennial that may be used as a groundcover in limited areas. Inch-long leaves, spoon- or lance-shaped are spread along thin stems up to 2 ft. long, rising above clumps of dense foliage. Poppy-like magenta leaves  are nearly ever-blooming without deadheading.  

Hesperaloe parviflora, called red yucca from southwestern U.S., grows in drought-tolerant clumps of arching, dark green, tough, narrow leaves 3-4 ft. long. Tall stalks bearing many coral-red, tubular flowers similar to aloe attract hummingbirds for weeks in summer. 

Mangave hybrids of Manfreda and Agave are fairly new to gardeners and have become eagerly sought after. They grow faster than parents and are somewhat more moisture tolerant. Hallmarks are their interesting leaf markings and colors and various shapes. Some develop tight expanding rosettes only 1 ft. tall while others with a more open leaf arrangement reach as much as 2 ft. x 4 ft. Silvery spotted leaves, crenated margins, pink or yellow variegation are popular features. Some prefer shade and winter protection.

Pachyphytum oviferum, called sugar almond or moonstones, bears chunky, silver-toned leaves with rose tints on stems up to a foot or so tall. Keep soil dry but with adequate water to maintain plumpness; protect in winter.

May 2023