Cistus albidus (White Leaf Rock Rose)
Cistus albidus, commonly called grey-leaf cistus or white-leaf rock rose, is a bushy evergreen shrub with tough greyish-white hairy leaves and fragile lilac-pink flowers that have a crumpled tissue paper appearance. The flowers only last one day, but new ones bloom every day during the spring and summer.
Cistus Albidus is a drought-tolerant shrub native to the Mediterranean basin and appears naturally in the Mediterranean shrublands. They reestablish quite successfully after the wildfires, which are so common in hot and dry landscapes.
HEIGHT & WIDTH
White Leaf Rock Rose scientific name
- Botanical name: Cistus albidus (SIS-tus AL-bi-dus)
- Family: Cistaceae (SIS-TAY-see-ee)
- Common name: Grey leaf cistus, White leaf rock rose, White rock rose
|Cistus||Comes from the Greek word “kisthos”, meaning box, basket. Related to the shape of its fruits.|
|albidus||The Latin word for white. Refers to the grey-white colour of its leaves.|
The names albidus and white rock rose are misleading because they refer to the greyish-white leaves rather than the flower, which is usually lilac-pink (although there are some less common white forms found in the wild)
How to identify Cistus albidus
Cistus albidus is a compact, bushy evergreen shrub with an upright form.
The branches are greyish in colour, the leaves greyish-white and the flowers lilac-pink.
There is an interesting contrast between the leaves, which are very tough and the very fragile flowers.
Although the shrub is evergreen, the leaf can fall in colder winters but will sprout again in the following spring.
It usually reaches 40 cm to 1 m (1.3 to 3.2 ft) in height after 5 to 10 years. But sometimes can grow up to 2 m tall. It spreads to 1 m (3.2 ft) wide.
The stems are greyish-brown and hairy with opposite, simple leaves at each node. The flowers appear in clusters at the ends of the stems.
The stem and leaves have a sticky substance called labdanum, an intensely fragrant resin that adheres easily to hands and clothes.
The rough leaves are greyish-green and densely covered with short hairs on both sides, giving them a greyish-white appearance.
They are fairly large with an oblong to elliptic shape of 1.5 to 6.5 cm (0.6 to 2.5 in) long by 0.5 to 2 cm (0.2 to 0.8 in) wide.
The leaves have a slightly undulated margin, three prominent veins and no stalk (sessile).
The lilac-pink flowers are very showy and delicate, appearing in terminal clusters of one to seven individual flowers.
Each flower has 5 petals with a crumpled tissue paper appearance and 5 sepals. At the centre are numerous orange stamens and one pistil. The lilac-pink colour of each petal fades into a yellow stain at the base.
The flower size is around 0.5 to 3 cm (0.2 to 1.2 in).
The flowers usually bloom in spring and summer but are very short-lived, lasting only a few hours. They open early in the morning, and the petals fall shortly after midday. But new flowers bloom every day for many weeks.
The fruit is an ovoid hairy capsule inserted in the calyx. It opens into 5 valves containing a large number of seeds.
The fruit size is 0.7 to 1.3 cm (0.3 to 0.5 in).
The seeds are very small, 1 to 1.5 mm (0.04 to 0.06 in), and have a hard, water-impermeable brown coating.
Cistus albidus Usage
Although the cultivation of Cistus albidus in nurseries is relatively recent, it is a very attractive ornamental plant with many showy lilac-pink flowers with a crumpled tissue paper appearance.
It can be used as a solitary plant or planted in groups with other cistus types or other drought-tolerant plants. In beds, borders or in containers. In rock or gravel gardens. They are particularly interesting for drought-tolerant and low-maintenance gardens.
Cistus albidus has been used for a long time in popular medicine. But studies have also demonstrated its therapeutic potential with analgesic and anti-inflammatory properties.
Reforestation in dry regions
Cistus albidus is a very robust plant that can survive extreme weather conditions, namely prolonged droughts. It can also regenerate after wildfires which makes it interesting for reforestation after forest fires that burn all the existing vegetation.
During the growth period, the plant drops its seeds in the soil, which can remain dormant for long periods. However, the fire’s intense heat causes the seed coat to crack, and the surviving seeds germinate shortly after the fire.
Cistus albidus is a melliferous flower with lots of pollen that attracts bees and numerous other insects, enriching the biodiversity in your garden.
The roots of Cistus shrubs have the ability to create a mycorrhizal relation with truffle mushroom fungi. In this relationship, the truffles provide nutrients to the Cistus in exchange for carbohydrates.
Several studies are analysing their possible usage as host plants for truffle cultivation. The advantage is that Cistus shrubs are much smaller than traditional hosts such as oaks and pines and could therefore lead to higher production for the same area.
How to plant and care for Cistus albidus
Cistus plants are native to the Mediterranean basin, so they are adapted to hot, dry summers and mild, moist winters. Usually, they are not very hardy, however, Cistus albidus is one of the hardiest species and can tolerate temperatures down to -10ºC (14ºF).
However, the plant will need winter protection during the first few years. You should cover the root area with mulch to protect the roots from severe frosts and very low temperatures.
Cistus albidus likes poor, well-drained, light sandy soils. It can tolerate most types of soils, from mildly acidic to mildly alkaline.
This shrub needs full sun to thrive and does not like to be watered.
Cistus albidus is a very robust plant and usually does not have problems with pests and diseases.
The best time to plant this shrub is at the beginning of spring for colder regions or the beginning of autumn for warmer regions.
How to water Cistus albidus
Cistus albidus is a drought-tolerant plant and does not like humid soils. Once established it no longer requires watering.
During its evolution, it developed mechanisms for drought tolerance:
- Dense hair in the branches and leaves to trap moisture
- Symbiotic relationship with mycorrhizal root fungi that provide water and nutrients in exchange for carbohydrates.
During the first two years after planting, you will need to water the young Rock rose every two to three weeks during the summer. Allow the soil to dry out between watering.
When watering it, you need to do it abundantly, giving the soil a generous soak so the water can penetrate deeply into the soil to allow the roots to grow deeply.
To preserve the soil´s moisture, you should add mulch around the root area of the Rockrose (but not too close to the base). Wood chips and gravel are good options for mulching.
How to prune Cistus albidus
Cistus albidus does not require any pruning. Actually, it does not like being pruned or having its roots disturbed.
How to propagate Cistus albidus
Rock roses can be propagated by seed, but it is not easy. The easiest method of propagation is by cuttings.
- Softwood cuttings Take these cuttings, from a non-flowering shoot, in early summer. They root easily in up to 4 weeks.
- Semi-ripe cuttings can be taken from late summer to late autumn. Semi-ripe cuttings can be placed in a cold frame over winter.
- Hardwood cuttings taken in late winter, just before new growth starts, will root easily.
Other Cistus you may also like
Sources of information used for this article
Article from Floresyplantas.net
Article from http://temperate.theferns.info/
Article from https://www.jardineriaon.com/
RHS Propagating Plants: How to Create New Plants For Free by Alan Toogood and Royal Horticultural Society
Field Guide to the Wildflowers of the Western Mediterranean, Second edition Paperback – 1 Oct. 2021 by Chris Thorogood