Helianthemum — Sunrose
Helianthemum nummularium is one of the very few low-growing, sun-loving, evergreen shrubs for the garden. In mid-spring to summer, plants are covered with small, single or double five-petaled blossoms in a wide array of bright or pale colors in shades of pink, peach, red, orange, yellow, or white—all with a tiny, bright yellow center.
Commonly called sunrose, this drought-tolerant mini-shrub is sometimes confused with the much larger growing and closely related Cistus shrubs known as rockroses whose flowers are much larger. Both are in the Cistaceae family and bear blooms reminiscent of certain roses.
Flowers on Helianthemum last only a day, but new buds are prolific and manage to keep the blooms constant for several weeks in late spring thru early summer when they attract butterflies. Shearing off faded flowers and stems helps maintain an attractive shape and encourages a repeat bloom.
For the rest of year, these little mounding shrublets are appreciated for their foliage and form. They fit neatly into rock gardens; accent annual, perennial, or bulb plantings; or provide a low border or hedge along walkways or garden beds.
Keys to their continuous good looks are three-fold: plant in a sunny site, prepare lean soil with excellent drainage, and apply little watering in the dry months. Sunroses grow quite well in gravelly sites and are long-lived in clay, only if it is incorporated with gritty amendments such as perlite or small lava rock and formed into a raised mound. Elevating plants slightly above the surrounding soil level provides them with improved drainage.
Little to no fertilizer is needed. It is wise to avoid high nitrogen products that promote succulent growth that merely flops over unattractively. The healthiest plants develop thick leafy growth atop closely set woody stems at the base and reach less than 1 foot tall and wider. Occasional shearing helps keep then neat. Helianthemums are pest-free and resist deer.
‘Wisley Pink’ is a popular selection for its slightly fuzzy silver gray leaves and large pure pink flowers. ‘Henfield Brilliant’ leaves are the same silvery gray but flowers are coppery orange. Foliage on ‘Stoplight’ is infused with green that shows off its brick-red blooms.