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The Plantsman

Haemanthus and their cultivation

Graham Duncan discusses the habitats and characteristics of the species and gives detailed advice for the grower

Grown for their striking brush-like flowerheads and curious leathery leaves, Haemanthus is an entirely southern African genus of some 22 geophytic species belonging to the Amaryllidaceae. Endemic to South Africa, the southern parts of Namibia and the mountain kingdoms of Lesotho and Swaziland (Duncan 1989), the genus takes its name from the Greek haima meaning blood, and anthos meaning flower. This refers to the reddish colour of the flowers of H. coccineus and H. sanguineus, two of the first-described species in this genus.

Known locally under a plethora of mainly Afrikaans common names and almost as many English ones, H. coccineus is without doubt the most recognisable member of the genus to residents of the Western Cape, with H. sanguineus a close second. Both are widely known as April Fool lilies here for their tendency to bloom around 1 April following early autumn rains.

Ornamental qualities

Bulbs of H. coccineus collected at the Cape of Good Hope first reached Europe in the early 17th century. They were possibly the first South African plants to be brought into flower there and are known to have flowered at Middelburg in the Netherlands in 1604. The genus has always enjoyed great popularity, and some of its most appealing qualities are the sudden appearance of dense umbels of erect or spreading flowers with prominent yellow anthers surrounded by colourful succulent involucral bracts, its showy cluster of round, scented berries and the smooth, spotted or hairy scape in shades of red, pink or green. In addition, the remarkable variation in leaf form and orientation commands attention. The leaves range from being prostrate and densely hairy (H. pubescens subsp. pubescens) to erect and curiously sticky (H. nortieri), while some are attractively barred with maroon on the undersides (H. barkerae). The beautifully tunicated fleshy bulbs are also noteworthy.

The curious, spoon-shaped, solitary leaf of Haemanthus nortieri (above left) has a leathery texture and stands bolt upright. Both the upper and lower surfaces are sticky, hence the covering of sand grains. Haemanthus sanguineus (above centre) has broad, prostrate leaves. The strap-shaped leaves of H. pubescens subsp. pubescens (top right) are covered with erect white hairs. These three deciduous species are winter-growing and have red inflorescences, although those of H. pubescens are sometimes white

Decoctions of H. coccineus and H. sanguineus bulbs have been used by the indigenous peoples of the Western Cape since the 18th century as a diuretic for treating dropsy and as an asthma remedy. The bulb scales are said to have antiseptic properties and are employed to treat flesh wounds, while the leaves are used to keep wound dressings moist.

Distribution

The genus is concentrated in Namaqualand in the arid northwestern part of South Africa where 15 species occur almost exclusively in the winter rainfall region. Six species are found in the summer rainfall region and only H. albiflos is known from both regions (Snijman 1984). The genus occurs in a wide range of habitats, from coastal dunes in deep white sand just above the high water mark (H. pubescens subsp. pubescens), to seasonally inundated gravelly-clay flats (H. pumilio) or seasonal acid bogs (H. canaliculatus), and from shaded cliff ledges (H. pauculifolius) and rocky outcrops (H. coccineus, H. humilis) to mountain tops and steep slopes (H. sanguineus, H. unifoliatus). Certain species such as H. albiflos and H. coccineus are common and fairly widely distributed. Others are naturally rare and some, such as H. canaliculatus and H. pumilio from the southwestern Cape, have become critically endangered due to housing and industrial development.

In their mountainous Western Cape habitat, several Haemanthus species are stimulated to profuse flowering following summer bush fires that periodically clear away choking vegetation, creating spectacular autumn displays. The fynbos (heathland) endemic H. canaliculatus flowers particularly well following a fire, and H. coccineus and H. sanguineus are similarly strongly stimulated.

Flowering in most Haemanthus is fairly frequent in the wild but under cultivation it is highly erratic in species such as H. graniticus and H. nortieri. Judging by the bulb size reached by some species including H. coccineus and H. sanguineus in the wild, these must easily be capable of reaching several decades in age, probably more.

Common species

The three white-flowered, evergreen species make very tolerant houseplants. Haemanthus pauculifolius (above left) is distinguished from the other two by its solitary leaves. The short-scaped inflorescence and leaves that are as broad as they are long separate H. deformis (above right) from H. albiflos (centre)

The most commonly grown species worldwide is the highly variable, evergreen and virtually indestructible H. albiflos, a most obliging and free-flowering plant that thrives on benign neglect. The two other evergreen species, H. deformis and the recently described H. pauculifolius (Snijman and van Wyk 1993), are also widely distributed as houseplants and their identities are sometimes confused. The key and photographs on this page should help distinguish them.

Haemanthus coccineus is also widely grown and successfully maintained outdoors in mild climates, including Tresco Abbey Gardens on the Isles of Scilly where a planting of H. coccineus provides a bold display of reddish-orange in the Pebble Garden.

Haemanthus are especially attractive to the bulb connoisseur due to their varied flowering times in autumn, spring and summer, and suitability to differing conditions of light, from full sun to dappled or even deep shade. Also, the deciduous nature of most species gives an added element of interest.

Haemanthus and Scadoxus

Considerable confusion still exists among many gardeners and horticulturists as to the morphological differences that separate Haemanthus and Scadoxus. Previously included under Haemanthus, Scadoxus is distinguished primarily by its rhizomatous rootstocks and thin-textured leaves with distinct midribs. This contrasts with the true bulbs of Haemanthus with succulent leaves that have no midrib (Friis and Nordal 1976). The leaves of most Scadoxus are arranged alternately on a distinct pseudostem whereas in Haemanthus a pseudostem is absent and the leaves are either single or arranged in opposite rows. Scadoxus occurs mainly in tropical Africa (Duncan 2001) but is also represented in southern Africa whereas Haemanthus is restricted to southern Africa.

Varying growth periods

The wide variation in leaf form, texture and orientation, the dense showy umbels enclosed by colourful involucral bracts, and the attractive ripe berries afford Haemanthus high specialist collector value. The genus consists of both deciduous and evergreen members and there are three distinct growth types: deciduous winter-growers, deciduous summer-growers and evergreen species.

The winter-growers account for the vast majority of species and comprise H. amarylloides, H. avasmontanus, H. barkerae, H. canaliculatus, H. carneus, H. coccineus, H. crispus, H. dasyphyllus, H. graniticus, H. lanceifolius, H. namaquensis, H. nortieri, H. pubescens, H. pumilio, H. sanguineus, H. tristis and H. unifoliatus. Members of this group flower from late summer to late autumn and have leaves that appear shortly after flowering and grow throughout the winter months, dying back in early summer. The only two deciduous summer-growers, H. humilis and H. montanus, produce new leaves in early summer and flower shortly afterwards or up until late summer. There are three evergreen species, H. albiflos, H. deformis and H. pauculifolius. These flower mainly from autumn to early summer.

Species with erect, spoon-shaped single leaves (H. nortieri and H. unifoliatus) or pubescent leaf surfaces (H. dasyphyllus, H. pubescens subsp. pubescens, H. unifoliatus, certain types of H. deformis and most types of H. humilis) are worth growing for these features alone, as well as those with undulate leaf margins (H. crispus and H. namaquensis).

The starry pink flowers of Haemanthus carneus (left) appear atop a sturdy, dull maroon scape clothed in short soft hairs. Haemanthus humilis subsp. humilis (right) with its rose-pink flowers is superficially similar to H. carneus but the prominent, exserted stamens help distinguish it. Haemanthus pubescens subsp. pubescens (centre) is a winter-growing species that occurs in colonies along the southwestern Cape coast

Cultivation

Those that are most highly recommended for cultivation due to their combined attributes of visual floral appeal and reliable flowering performance are H. amarylloides, H. carneus, H. coccineus, H. crispus, H. deformis, H. humilis, H. sanguineus and the better forms of H. albiflos.

With strict adherence to relevant growth and dormancy periods, watering procedure, growing medium and aspect, Haemanthus are generally easily cultivated and long-lived bulbous plants. The growing medium must drain sharply and at Kirstenbosch Botanical Garden, South Africa, excellent results have been obtained with deciduous winter- and summer-growers using a mixture of equal parts of coarse river sand or grit, and finely sifted compost. For the evergreens the amount of compost can be increased to two parts (Duncan 1998, 2000). Haemanthus are not particularly fussy as to soil pH, except for the southwestern Cape endemic H. canaliculatus. This has a definite requirement for an acid, sandy growing medium and a 2-3cm layer of compost is placed at the base of containers into which the roots can grow if they wish.

For larger species or those that multiply readily, such as H. albiflos, H. coccineus, H. deformis, H. montanus, H. sanguineus and the larger forms of H. humilis, a 30cm diameter pot is recommended, while for medium-sized or slow-growing species including H. amarylloides, H. carneus, H. graniticus, H. lanceifolius and H. nortieri, a 25cm diameter pot is most suitable. Smaller species and those that are harder to grow such as H. barkerae, H. crispus, H. dasyphyllus, H. namaquensis and H. unifoliatus do best in a 20cm diameter pot.

Haemanthus bulbs like to be slightly pot-bound and prefer to remain undisturbed for at least five years or until growth and flowering performance deteriorate. In cold climates terracotta pots are appropriate but in warmer parts these dry out too rapidly and plastic containers are more suitable.

Bulbs of the winter-growers are best planted with the top of the neck at soil level, with the exception of
H. namaquensis whose bulbs are more successfully placed with the upper third exposed to lessen the risk of rotting. Bulbs of summer-growing H. montanus also do best with the neck at soil level while those of H. humilis and the evergreen species like to be exposed by about one-third.

For all Haemanthus species (and most southern African amaryllids), heavy drenching at well-spaced intervals that allows the medium to dry out almost completely, is always preferable to frequent superficial watering. Winter-growers respond strongly to a single heavy drench in early autumn, often sending up their flowerbuds within a matter of days. Watering should then be witheld until after flowering, applying a drench every 10 days or fortnight.

Certain arid-adapted winter-growers such as H. dasyphyllus, H. namaquensis, H. tristis and H. unifoliatus are sensitive to root rotting due to overwatering, and require extra vigilance in this respect. The summer-growers should receive their first drench in late spring, repeated roughly every 10 days, and the same applies to the evergreens. The evergreens need regular watering in summer but much less during the winter and are remarkably drought tolerant during this period.

All Haemanthus species are frost tender and make excellent subjects for a cool glasshouse in cold climates. In temperate gardens and warmer parts of the southern hemisphere, tougher winter-growers such as H. coccineus and H. sanguineus are ideally suited to raised beds or rock garden pockets in full sun, while most other winter-growers do best in pots.

Semi-shaded positions suit summer-growing H. carneus and H. humilis as well as evergreen H. albiflos and H. pauculifolius, while evergreen H. deformis is particularly useful to the gardener as it requires deep shade. When grown in containers, the preferred aspect for both winter- and summer-growing species is one receiving morning sun and afternoon shade, or bright light for as much of the day as possible.

Supplementary feeding is not recommended for Haemanthus as their nutritional requirements are sufficiently catered for in the compost component of the growing medium. Fertilisers high in nitrogen are, in fact, detrimental as they promote excessive leaf growth at the expense of flowers. This results in plants becoming more susceptible to disease. Winter- and summer-growing species must be given a completely dry dormant period for optimum results, and even the evergreens benefit from much less moisture over the winter months.

Pests and diseases

All Haemanthus are highly susceptible to attack by mealybugs that hide and multiply between the bulb tunics and just below the leaf bases, especially when grown in containers under glass. A systemic insecticide containing imidacloprid is suggested as a measure of control. In countries where this is available as a drench
it can provide protection for up to one year from a single, thorough application in early autumn for winter-growers, and in early spring for summer-growers and evergreens. In the UK it is only available as a foliage spray which is less effective against this type of pest. Disposing of infested plants and putting new acquisitions into quarantine until found to be free of infestation is a further means of keeping a bulb collection free of mealybugs.

Slugs and snails are partial to the foliage of broad-leaved species, which may also come under attack from lily borers (amaryllis caterpillars), a devastating pest widely prevalent in southern Africa but not in the UK.

Fungal rotting of roots and bulbs is rare in evergreen Haemanthus, but frequent in deciduous species from arid areas like Namaqualand, and is almost always the result of overwatering during the growing period, an insufficiently well-drained growing medium, or failure to dry out the soil adequately over the appropriate dormant period.

The roots may also become infested with nematodes, which are best controlled by soil sterilisation. However, soil-sterilising chemicals are not available to amateur gardeners in the UK.

Propagation

Haemanthus can be propagated by seed and offsets, and from bulb and leaf cuttings. Propagation by seed is the most reliable manner in which to increase stocks, but seed of rarer species is difficult to come by. The seeds are contained in rounded or ellipsoid berries that become soft and fragrant when ripe, and are often brightly coloured in shades of orange, red or pink. Remove the fleshy seeds once the berries have become soft by washing them in water until most of the pulpy outer covering has come off. As they are non-dormant, sow them immediately in deep seed trays or pots. Use a sharply drained medium of equal parts of coarse river sand or grit and finely sifted compost. Position the seeds individually on the surface to provide sufficient space around each seedling, then simply press them into the medium to lie just below soil level.

Place containers in a protected, semi-shaded position and water heavily every 10 days using a fine rose. Germination takes place within two months and seedlings should remain undisturbed for two growing seasons before planting them individually into permanent pots at the start of their third season. Under ideal conditions, H. albiflos and H. humilis can be brought into flower in their third year, while other species may take four or more years. Growing the intriguing H. nortieri from seed requires exceptional patience. A seed sown in autumn 1979 at Kirstenbosch flowered for the first time 17 years later!

All species except H. amarylloides, H. sanguineus and H. unifoliatus produce offsets (daughter bulbs). Species that multiply readily by this means are evergreen H. albiflos and H. pauculifolius, and, to a lesser extent, H. canaliculatus, H. coccineus, H. deformis, H. humilis and H. pubescens. Offsets can be separated in the dormant period but are more successfully removed as the new leaf growth begins, either in late autumn for winter-growers and evergreens, or in early summer for summer-growers. Detach offsets from the mother bulb by gentle tugging, not forcible pulling, and treat any damaged surfaces with a fungicide. Replant as soon as possible to prevent the perennial fleshy roots from drying out.

Propagation by bulb cuttings is rarely used, as seldom is anyone prepared to sacrifice a mature bulb without guarantee of success. It is best done at the beginning of the growing season when the bulb should be cut into longitudinal sections, each containing a portion of the basal plate. The sections are placed upright, with the tips exposed, in a moist rooting medium such as equal parts of river sand or grit and peat moss. After a few weeks young bulblets will begin to form on the cut surfaces of the basal plate, and can be removed at the beginning of the next growing season and potted-up individually.

The induction of bulblets near the base of severed leaves is successful only in H. albiflos, as far as I am aware. Remove entire leaves from the bulb, including as much of the basal portion of the leaf as possible, and place into the same medium suggested for bulb cuttings, with the lower third below soil level. Bulblets form just above the cut area within a few months.

Vegetative key to the evergreen species of Haemanthus

1a Leaves solitary, narrowly tongue-shaped, always pubescent on upper and lower surfaces H. pauculifolius
1b Leaves 2, 4 or 6, broadly tongue-shaped or about as broad as long, glabrous or pubescent on upper or lower surfaces 2
2a Leaves 2, 4 or 6, broadly tongue-shaped, usually glabrous but sometimes pubescent on upper or lower surface, apex acute or rounded H. albiflos
2b Leaves 2 or 4, about as broad as long, glabrous or pubescent on upper or lower surface, apex blunt H. deformis

References

Duncan, G D (1989) Haemanthus. In Du Plessis, N M and Duncan, G D Bulbous Plants of Southern Africa. Tafelberg Publishers, Cape Town
Duncan, G D (1998) The Kay Bergh Bulb House. Veld & Flora 84(3): 80–81
Duncan, G D (2000) Grow Bulbs. Kirstenbosch Gardening Series. National Botanical Institute, Cape Town
Duncan, G D (2001) Spectacular, rewarding Scadoxus. Veld & Flora 87(2): 60–63
Friis, I and Nordal, I (1976) Studies on the genus Haemanthus (Amaryllidaceae) IV. Division of the genus into Haemanthus s. str. and Scadoxus, with notes on Haemanthus s. str. Norw. J. Bot. 23 (2): 63–77
Snijman, D A (1984) A revision of the genus Haemanthus L. (Amaryllidaceae). J. S. Afr. Bot. Supplementary volume 12, National Botanical Gardens, Cape Town
Snijman, D A & van Wyk, A E (1993) A new species of Haemanthus (Amaryllidaceae) from the eastern Transvaal Escarpment, South Africa. S. Afr. J. Bot. 59(2): 247–250

Graham Duncan is the specialist horticulturist for southern African bulbous plants at the National Botanic Garden, Kirstenbosch, South Africa