Eulophia horsfallii ( sometimes called E.rosea) is a magnificent, tall-growing, purple-flowered
orchid found in KwaZulu-Natal, Mpumalanga and Limpopo [Northern
Province] in South Africa as well as in Swaziland and further north
in tropical Africa. In a remarkable adaptation from the humid, summer
rainfall and winter drought conditions of its natural habitat, this
species has become naturalized at Kirstenbosch Botanic Garden under
seemingly unsuitable conditions of heavy winter rains and dry summer
a staggering 2.3 m high in full flower, E. horsfallii is
a large terrestrial orchid, producing several broad, erect, heavily
pleated leaves and a robust flower stem carrying up to 40 large
purple flowers with cream-coloured, crested lips. It often remains
evergreen under cultivation in temperate climates but is deciduous
and summer-growing in the wild, and has a subterranean, rhizomatous
rootstock consisting of persistent pseudobulbs linked together by
short, cylindrical stems, similar to those of the popular orchid
E.horsfallii has a wide distribution in Africa, occurring
from northern KwaZulu-Natal in a northerly direction into Swaziland,
Mpumalanga and Limpopo in South Africa, and further north to Sudan,
west to Angola and Congo, and along the coastal parts of West Africa.
Derivation of the name and historical aspects
The generic name Eulophia is derived from the Greek eu,
meaning well, and lophos, meaning crested, and alludes to
the prominently crested lip or labellum, situated below the two
lateral petals of the flowers of this genus. This species has recently been referred to as E.rosea see below. The specific epithet
Mr J.B. Horsfall, who cultivated and flowered the type material
of this species, collected in West Africa, in his glasshouse in
England, and which was beautifully illustrated in Curtis's Botanical
Magazine in 1865.
In June 2011 SANBI received the following interesting communication from Mr Peter Morrall:
"My great grandfather, George Morrall, head gardener and estate bailiff to Thomas Berry Horsfall, was the first to cultivate a species of orchid new to England, when Mr. Horsfall was sent a plant specimen from Mr. S. Cheetham, Calabar River, Nigeria, in 1861. Thomas Berry Horsfall was a Member of Parliament and a shipping merchant working out of Liverpool. The orchid flowered in the glasshouses at Bellamour, Colton, Staffordshire, in 1864, and was subsequently registered in London by George Morrall, with the name ‘Lisochillus Horsfallii'. The species was reported lost to cultivation until March 1906, when Mr. Walter Rothschild, of Tring Park, Hertfordshire, received a silver gilt Flora Medal from the Orchid Committee of the Royal Horticultural Society."
However, it later became apparent that this plant had earlier been described as Lissochilus roseus by John Lindley in 1844, and illustrated the same year in Edwards's Botanical Register. Then, in an issue of Orchid Review in 1964, A.D. Hawkes transferred Lissochilus roseus to the genus Eulophia as E. rosea, and placed Eulophia horsfallii in synonymy, however this seems to be in dispute now.
In its natural habitat, E. horsfallii grows in humid, dappled shade
on swamp forest margins. The individual flowers are long lasting
(up to two weeks) and the flowering period is lengthy, beginning
in September and extending to March, with a peak flowering period
between November and the end of February. At Kirstenbosch its flowers
are pollinated by large, black-and-yellow bumblebees that result
in the formation of large, green, pear-shaped seed capsules. The
tiny dust-like seeds of orchids are very well adapted to wind dispersal,
and this undoubtedly accounts for the spontaneous appearance of
numerous plants of E. horsfallii in the Camphor Avenue at
Kirstenbosch, a short distance from the bulb nursery where the original
plants are cultivated in large containers. Evidently, ideal conditions
of moisture, light, temperature and a suitable fungus exist between
the decomposing logs (that form the terraces in the Camphor Avenue)
for seed germination and development to occur there. Plants of E.
horsfallii have also spontaneously appeared relatively long
distances away from the bulb nursery, including the grounds surrounding
the Gold Fields Education Centre, and in a swampy patch near the
Harry Molteno Library.
Growing Eulophia horsfallii
E.horsfallii grows well in full sun but prefers a protected,
lightly shaded position such as that provided by established evergreen
trees with a high canopy. Under all-day full sun conditions the
leaves tend to burn, and strong winds cause the leaves to tear and
look unsightly. A loamy, slightly acid soil containing well-decomposed
compost is preferred, and the plants grow equally successfully under
well-drained or waterlogged conditions. At Kirstenbosch Gardens
they easily survive heavy winter rainfall and remain largely evergreen,
sending up their new leaves in spring and summer, before the old
leaves have died down. In summer rainfall areas experiencing cold,
dry winters, the plants become dormant over the winter period. Once
established, the clumps plants like to remain undisturbed for several
years and rapidly form thick clumps. This species can also be successfully
cultivated in large, deep plastic pots with a diameter of at least
35 cm. Frequent, heavy watering is required in summer, especially
for container grown plants that need drenching twice weekly.
Division of E. horsfallii clumps is the only feasible method
of propagation for the home gardener. Thick clumps are best separated
in early spring, just before the new leaf shoots begin to develop.
The rhizomatous rootstock consists of persistent pseudobulbs which
are usually entirely subterranean, and linked by short, cylindrical
stems. The rootstock forms branches with age, and these branches
can be separated, ensuring that each branch is removed with a growing
point. Separated branches must be replanted immediately, and kept
well watered, and will require a year or two of good growth before
flowering commences again. The major reason that most orchids (including
Eulophia) cannot be raised successfully from seed when sown
in the normal way is that the seedlings of most of them are dependent
for survival on a symbiotic association with a specific fungus.
Symbiosis refers to the association of two different organisms living
attached to each other, or one within the other, usually to the
advantage of both. In the instance of orchid seeds, the fungus penetrates
the roots of the seedling and through the exchange of nutrients,
nutritional benefit is obtained by the seedling, and usually by
the fungus as well. Further requirements for successful germination
of most orchid seeds include sufficient moisture and favourable
temperature and light levels.
As with most Eulophia species, the foliage of E. horsfallii
is highly susceptible to infestation by red spider mite in summer,
seen as a silvery bronze sheen over the lower leaf surface. The
developing flower buds frequently fall prey to attack by aphids
and thrips at the height of summer, resulting in malformed blooms.
- DUNCAN, G.D. 1989. Eulophia. In N.M. Du Plessis &
G.D. Duncan, Bulbous plants of southern Africa. Tafelberg,
- DUNCAN, G.D. 2000. Eulophia horsfallii at Kirstenbosch. Veld
& Flora 86: 16-18.
- HAWKES, A.D. 1964. Notes on Lissochilus and Microstylis. Orchid Review 72: 27
LINDER, H.P. & KURZWEIL, H. 1999. Orchids
of southern Africa. Balkema, Rotterdam.
POOLEY, E. 1998. A field guide to wildflowers
of KwaZulu-Natal and the Eastern Region.Natal Flora Publications
Kirstenbosch National Botanic Garden
May 2003 Updated 2011. Updated further 2013