Helianthemum - Rockrose

Helianthemum (rockrose, sunroses, rushrose, or helianthemum) is a genus of about 110 species of evergreen or semi-evergreen subshrubs. They are widely distributed in the Americas, Europe, and from North Africa to Asia Minor and Central Asia, with the centre of diversity in the Mediterranean region.

The leaves are opposite, simple oval, 1-4 cm long and 0.5-2 cm broad, varying from glossy green to tomentose grey-green. The flowers are 2-4 cm diameter, with five petals, white or yellow, occasionally tinged pink; in some species the flowers are bicoloured with a brighter yellow centre to act as a 'target' for pollinating insects.


Cultivation and uses
Several Helianthemum species, and the numerous hybrids and cultivars derived from them, are widely grown as ornamental plants, popular in rockeries. A broader range of colours is available among the cultivars, including bright salmon-pink to dark red.


Selected species
Helianthemum apenninum, the white rock-rose, is a white-flowering rock rose found in dry grassy and rocky places across large parts of Europe. Helianthemum apenninum flowers from March to July, and may grow up to 50 cm tall. The flowers are pentamerous, up to 30 mm across, and are white with yellow centres and yellow stamens. The three outer sepals are hairy and striped; the 2 inner sepals are very small. The flowers grow in clusters of 3 to 10 on a stem. The leaves are linear to lance-shaped, 30 mm long, in opposite pairs. They are covered with greyish or whitish hairs, especially on the underside, and the edges are rolled under.

Helianthemum canum, commonly called Hoary rockrose, is a low growing plant confined to rocky dry calcareous areas especially close to the sea. The plant typically has a central stock from which numerous branches radiate horizontally or ascending. The small leaves about 10mm long are simple and green above but denseley hairy and grey below. The bright yellow flowers have 5 petals and 5 sepals in cymes generally with 1 to 6 flowers in each cyme.

Helianthemum greenei is a rare species of flowering plant in the rock-rose family known by the common name island rush-rose. It is endemic to the Channel Islands of California, where it grows in the chaparral of the rocky seaside slopes. It is present on three or four of the eight islands, where it has historically been threatened by feral herbivores such as the Santa Cruz sheep and is making a gradual recovery. This wildflower is an erect perennial herb reaching a maximum height near 30 centimeters. Its leafy stem is mostly green, with new growth and inflorescences at the top often appearing purple in color. The leaves are narrow, linear, and pointed, up to three centimeters long. The inflorescence is generally a panicle, producing many buds which open into golden yellow flowers one to two centimeters wide. Each rock-rose flower has five rounded petals over five smaller, fuzzy-haired sepals. The fruit is an oval-shaped capsule half a centimeter wide.

Helianthemum guerrae is a species of plant in the Cistaceae family. It is endemic to Spain. Its natural habitat is Mediterranean-type shrubby vegetation. It is threatened by habitat loss.

Helianthemum marifolium is an endangered ornamental plant in the Cistaceae family.

Helianthemum nummularium (Common Rockrose) is a species of rockrose, native to most of Europe.

Helianthemum oelandicum is a flowering plant of the genus Helianthemum in the family Cistaceae.

Helianthemum scoparium is a species of rockrose which is endemic to California. Its common names include peak rockrose and peak rushrose, and one variety is known as Bisbee Peak rushrose. This is a small perennial shrub bearing long, smooth stems and small flowers each with five bright yellow petals. It is found in dry, sandy areas in hills and low mountains.

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