Drosanthemum hispidum – Hairy Dewflower
Drosanthemum hispidum, known in Polish as hairy drosanthemum and in English as hairy dewflower, purple dewplant, or rosea ice plant, is one of the most striking representatives of the ice plant family (Aizoaceae). This low, creeping succulent shrub from southwestern Africa belongs to the genus Drosanthemum, which comprises around 110 species characterized by shiny, transparent bladder-like cells on their leaves that resemble drops of dew. The species was first described by Carl Linnaeus in 1753 under the name Mesembryanthemum hispidum, and was transferred to the genus Drosanthemum by the German botanist Gustav Schwantes in 1927.
Two features have made this plant popular in horticulture: its exceptional resistance to drought and heat, and its profusion of star-shaped flowers in intense shades of purple and magenta, which can almost completely cover the leaves during the season. In Mediterranean climates, it is valued as ground cover for slopes, walls, and gravel gardens; in cooler regions of Europe, it is grown in containers, where its cascading shoots look equally attractive. Its versatility and modest requirements make it suitable both for succulent collectors and for gardeners looking for a “plant you can forget about”.
Botanical description and plant habit
Drosanthemum hispidum is a perennial, evergreen subshrub growing from 10 to 60 cm tall, and according to some South African sources, even up to 70 cm. Young shoots initially grow upward, then lie down and spread sideways, rooting where they come into contact with the soil. In this way, a single plant forms a dense, cushion-like mat 0.5–1 m wide. Older shoots become woody and develop light brown, peeling bark, while young shoots are green, fleshy, and densely covered with stiff, pale bristles - it is to these hairs that the species owes its Latin epithet hispidum, meaning “bristly”.
The leaves are opposite, cylindrical or slightly flattened, up to 2.5 cm long, and grayish green, sometimes with a reddish coating. Their surface is covered with large, convex epidermal cells filled with water, known as bladder cells, which refract light and make the entire plant look frosted or covered with dew in sunlight. Hence the generic name Drosanthemum, derived from the Greek words drósos (dew) and ánthemon (flower). These cells store water, reflect some solar radiation, and reduce leaf heating, while their salt content helps the plant tolerate saline soils.
Growth rate and development
The growth rate is moderate to fairly fast, especially in a warm, sunny position. According to the Royal Horticultural Society (RHS), the plant reaches its full size after 2-5 years of cultivation, although it usually forms a clearly defined, flowering clump as early as the second season. It spreads mainly sideways: the shoots grow longer, fall under their own weight and root at the nodes, allowing the clump to constantly renew itself from the edges, while its center may gradually become thinner and woody.
The plant is long-lived in the sense that it continuously produces new, rooted shoots, so in practice it can grow in one place for many years. To maintain a compact, dense habit, gardeners prune the shoots after flowering, which stimulates branching and thickens the mat. The plant is not invasive in the ground to the same extent as some Carpobrotus species, but in Mediterranean climates it can escape from gardens and become naturalized, as has been recorded in Italy, Spain and the Mediterranean islands.
Flowering and propagation
The flowers appear singly at the tips of short lateral shoots and are about 2-3 cm in diameter. Their structure is typical of Aizoaceae: what look like numerous narrow petals are actually transformed staminodes, while the true stamens form the light yellowish or whitish center. The petal color ranges from pinkish violet through purple to intense magenta, and their surface has a satin-like sheen in the sun. The flowers are photonastic - they open in full sun around noon and close in the evening and on cloudy days, so a sunny position is essential for enjoying them.
In nature, the species flowers in late winter and spring, after the rainy season, whereas in cultivation in the Northern Hemisphere the main flowering period falls in late spring and summer, often with repeated flushes lasting into autumn. The flowers produce nectar and pollen, eagerly collected by honey bees, bumblebees and solitary bees; in its native range, one of its specialized pollinators is Colletes schultzei. After pollination, small hygrochastic capsules develop; they open only under the influence of rain and eject the seeds with drops of water - an adaptation to a climate in which rainfall is rare and brief. In cultivation, the plant is also propagated vegetatively from stem cuttings or by separating rooted sections of the mat.
Origin and natural habitat
The natural range of Drosanthemum hispidum includes Namibia, the Cape Provinces of South Africa, and the Free State. The heart of this range is the Succulent Karoo - a semi-desert biome with winter rainfall, considered one of the richest succulent regions in the world. There, the plant grows on rocky outcrops, stony slopes, dry scrubland, and sandy plains, but it also appears in disturbed areas, along roadsides and on pastures, and even on saline soils. Only 150-400 mm of rain falls there annually, mainly in winter, while summers are hot and dry.
South African sources report that the species also occurs in the Karoo, in fynbos areas, and in coastal scrubland of the Eastern Cape, demonstrating its broad ecological tolerance. This adaptability explains why the plant has become established so easily in dry regions with similar climates: according to Plants of the World Online, it is introduced and naturalized in Spain, the Balearic Islands, the Canary Islands, and Italy, where it has been recorded, among other places, in Liguria and Sicily.
Environmental requirements and tolerance
This is a full-sun plant: in shade, the stems become elongated, the bladder cells lose their sheen, and the flowers are reluctant to open. The soil should be mineral-based, very well drained, and rather poor - sandy, gravelly, or rocky, with a neutral to alkaline pH. The plant tolerates intense heat (above 35 °C), wind, salinity, and sea spray, which is why it is often planted in coastal gardens. Its greatest enemy is excess water: in wet, heavy soil, the roots and stem bases quickly rot.
Hardiness is a subject on which sources differ considerably. The RHS rates it as H2 (a tender plant, with a minimum temperature of 1-5 °C), South African sources mention tolerance of light frosts, while some American rock-garden plant growers give a USDA hardiness range of 6a-9b, naturally for plants growing in ideally dry, gravelly soil. In practice, it should be assumed that brief frosts down to approximately -4 °C do not cause damage in dry soil, while lower temperatures or frost combined with moisture lead to damage. USDA zone 9 is the safe minimum zone for growing it outdoors in the ground.
Cultivation in a temperate climate
In cooler regions of Europe, Drosanthemum hispidum is best grown as a container plant. A wide, relatively shallow container with large drainage holes is suitable, filled with cactus mix supplemented with at least half coarse sand, gravel, perlite, or pumice. From late spring to autumn, the pot should be kept outdoors in the sunniest, most airy location: on a terrace, balcony, or external windowsill. Water generously, but only after the substrate has dried out completely, and fertilize no more than twice per season with diluted fertilizer for succulents.
In autumn, before the first frosts, move the plant to a bright, cool room - an unheated greenhouse, conservatory, cold porch, or bright stairwell with a temperature of 5–10 °C is ideal. In such conditions, water only occasionally, enough to prevent the leaves from becoming excessively wrinkled while keeping the substrate almost dry. Overwintering in a warm apartment with insufficient light causes the shoots to become elongated and weakens the plant. In regions with mild winters, in USDA Zone 9 and warmer, the species can be planted in the ground on well-drained slopes and rock gardens, preferably under an overhang that protects it from winter rain.
Uses in ornamental gardening
In Mediterranean climates and dry regions with mild winters, hairy dewflower is one of the classic ground-cover plants: it is used to cover slopes stabilized against erosion, the tops of retaining walls, gravel gardens, driveway edges, and gaps between paving slabs. It is also used in so-called xeriscaping, or water-wise gardening, and in coastal plantings, where salty breezes eliminate many other species. During flowering, extensive stands form uniform purple carpets visible from a distance.
In cooler regions of Europe, its place is in pots, bowls, balcony boxes, hanging baskets, and container rock gardens. Flower-covered trailing shoots create a spectacular cascade, while the glossy, “frosted” leaves are ornamental even outside the flowering season. The plant combines well with other succulents with similar needs - Delosperma, Lampranthus, sedums, echeverias, and Aloe - as well as ornamental grasses. For insect-friendly gardens, it is a valuable source of pollen and nectar in midsummer.
Cultural significance, history and etymology of the name
The species reached Europe among the first Cape plants imported by the Dutch East India Company and was already known to gardeners in the 18th century, since Linnaeus was able to describe it in Species Plantarum in 1753 as Mesembryanthemum hispidum. The large genus Mesembryanthemum was divided into dozens of smaller genera in the 20th century; Gustav Schwantes, a prominent researcher of Aizoaceae, separated the genus Drosanthemum in 1927 and transferred this species to it as well. The genus name refers to the “dew” covering the leaves, while the epithet hispidum refers to the bristles on young shoots. The Polish name drosantemum szczeciniaste is a faithful translation of the Latin name.
A phytochemical curiosity is the presence in the plant's tissues of the alkaloid 4'-O-demethylmesembrenol, related to compounds found in the famous South African plant Sceletium tortuosum (kanna). However, Drosanthemum hispidum is neither a medicinal nor a utility plant and is grown exclusively for ornamental purposes, as well as for protecting slopes against erosion.
Who this species is for
It is an excellent choice for people with a sunny balcony, terrace or windowsill who are looking for a plant that withstands neglect, heat and drought while also flowering spectacularly. It is suitable for beginners interested in succulents because it tolerates forgotten waterings, and its shoots root easily from cuttings. Collectors of Aizoaceae, designers of gravel gardens and owners of gardens in warm regions will also appreciate it, as it can serve as a permanent ground cover. The only requirement is to provide cool, bright and dry overwintering in regions with freezing winters.
Summary
Drosanthemum hispidum combines the resilience of desert succulents with a profusion of flowering rarely seen in plants with such modest requirements. Full sun, well-drained substrate and sparing watering are almost the entire philosophy of its cultivation. The species is widespread in nature and common throughout its range; it is not listed as threatened on the IUCN Red List, and on the national Red List of South African Plants, most common Drosanthemum species have Least Concern (LC) status, so its cultivation raises no conservation concerns.
