Lavandula — Lavender
The many stellar qualities of easy-to-grow lavender bring joy to many Sonoma County gardeners. It is impressively deer resistant and requires little water. Snails shun it. Bees and butterflies love it. Flower wands give a lovely sweet fresh scent to any room. Dried flower heads yield a delightful seed product that has been used for centuries to freshen fabrics and repel insects. It can even be used as a flavoring in delicate foods and beverages.
There are three main types of lavenders with over 40 named varieties. By planting several different types, lavender blooms decorate gardens for months.
The first to blossom in spring are the Spanish lavenders, Lavandula stoechas and its various named cultivars; ‘Otto Quast’ is popular and commonly planted. These are the showiest if not the most floriferous with small, pineapple-shaped tufts topped with upright, decorative bracts of purple, periwinkle, or even creamy white. When spent blossoms are regularly deadheaded, Spanish lavenders usually have a second or even third bloom period later in the summer. They are the most drought-tolerant of all lavenders.
English lavender, Lavandula angustifolia, is native not to England but to mountainous areas of southern Europe. It is the hardiest, although fairly short-lived, and must be replaced after 3-5 years. Blossoms appear on slender flower spikes in early summer and are much daintier and sweeter smelling than any of the Spanish lavenders. Named cultivars offer flowers in shades of blue and purple, white, or pink on mounds from 1½ -2 ft. tall and wide. Shearing off faded blossoms and stems helps maintain a compact shape and encourages some cultivars to repeat bloom. ‘Hidcote’ is a popular variety with intense blue-purple flowers; ‘Munstead’ is lavender-blue; ‘Jean Davis’ is pinkish white.
The lavandins or English lavender hybrids, Lavandula x intermedia, bloom last from mid-to late summer. These become quite shrub-like after several years in the ground, 2-4 ft. high and wide, depending on the cultivar. The most well known in this group are ‘Provence’ and ‘Grosso’, both valued for their intense fragrance and suitability for gathering, drying, and tying flower wands into bunches. Oil from ‘Grosso’ is used by the cosmetic industry; oil from ‘Provence’ is used in many lavender products. Both plants grow very quickly from a 1-gallon plant, but a 4-in. pot will reach the same size in about one year. These hybrids must be pruned regularly to prevent lower stems from becoming unattractively woody.
The most important requirements in planting lavender is to select a site with at least 6 hours of direct sunlight a day and to provide good drainage. It does not like soggy areas. Use compost and gritty material such as lava rock or perlite mixed well with the soil to improve aeration and allow roots to absorb nutrients without drowning.
Where soil is heavy or compacted, it is wise to create a small berm or mounds for each individual plant to avoid rain from puddling. When sited correctly and pruned judiciously, lavenders should live for five to seven years. Although lavender is fairly drought tolerant, adequate moisture is required throughout the growing season. Most critical are the weeks after planting to ensure that soil around the rootball does not dry out.
In late fall, lavenders may be pruned more severely but never into bare wood. Look for small green buds on lower stems and make cuts just above them. By pruning plants annually or more often in this way, they retain dense, leafy branching. Some can even be pruned close to the ground as long as buds are present.