Ixia viridiflora is one of the most striking and unusual
of our winter rainfall bulbous plants and very few plants can beat
it for sheer brilliance of flower.
It is a winter-growing, summer-dormant, deciduous perennial. The
rootstock is a corm, usually about 1 cm in diameter. It is one of
the taller ixias, with upright, narrow, grass-like leaves, 400-
550 mm long. The inflorescence is a lax, many-flowered spike with
12 to 20 flowers per spike, on a slender stem, 500 - 950 mm long.Each
flower is a brilliant turquoise-green with a conspicuous purple-black
circular stain or 'eye' in the middle. The dark eye is caused by
the deep blue sap of the cells of the upper epidermis. The green
colour is not produced by green pigment but is due to the effects
of light being refracted from striations in the cell wall and granules
embedded in the pale blue cell sap. The green ixia is particularly
showy, a number of flowers on the spike open together and persist
for several days without fading or falling off. In fact, this ixia
has more flowers open together at one time on one spike than any
of the other ixias. The flowers need sun and warmth to open, and
are at their best on hot still days. Flowering season is late spring
Ixia viridiflora is pollinated by hopliine scarab beetles, more
commonly known as monkey beetles (Family: Scarabaeidae; subfamily:
Rutelinae; tribe: Hopliini; the genera that do the pollinating include:
Anisonyx, Anisochelus, Heterochelis, Khoina, Lepisia, Lepithrix,
Pachycnema and Peritrichia). Beetle pollination appears
to have evolved convergently in many other southern African genera,
including Ornithogalum, Aristea, Sparaxis, Romulea, Spiloxene,
Arctotis, Ursinia, Wahlenbergia and Drosera. Flowers
that are beetle pollinated are typically salver- to shallow bowl-shaped,
brightly coloured with contrasting 'beetle marks' at the bases of
the petals/tepals, have no scent or odour, and produce little or
no nectar. The beetles visit the flowers to eat the pollen and whatever
little nectar is produced, to compete for mates and to copulate.
The pollen is deposited on or between hairs on the exoskeleton and
the beetles can be seen visiting one flower after another. Not all
ixias are pollinated by monkey beetles. There are species with narrow
tubular flowers and ample nectar that are pollinated by long-proboscid
flies, and a few others with tubular flowers that produce modest
amounts of nectar that are pollinated by a butterfly or by a combination
of monkey beetles and short-proboscid flies, and still more species
with cup-shaped nectar-producing flowers that are pollinated by
bees. There is no mechanism for ballistic dispersal of the seed,
the capsule dries and splits and seeds are scattered about the parent
as the stem weaves and bobs in the breeze.
Ixia viridiflora grows on the lower slopes of mountains
in the Tulbagh District of Western Cape. It was also recorded in
the Piketberg and Clanwilliam Districts by Marloth (1855-1931),
but is no longer found there. Sadly, it is listed as Vulnerable
in the Red Data Book, and is likely to be upgraded to Endangered
in the near future, if the decline in numbers continues.
The genus Ixia consists of about fifty species and belongs in the
Iris family. Ixia is endemic to the western and southern parts of
South Africa and its distribution matches almost perfectly with
the winter-rainfall region: from Namaqualand in the north west,
through to the Cape Peninsula, inland into the Karoo, and eastwards
to the southern parts of Eastern Cape. The highest concentration
of species occurs in the countryside around Caledon, Wellington,
Paarl, Stellenbosch, Tulbagh, Malmesbury, Piketberg and Clanwilliam.
Ixias are exclusively winter-growing, summer-dormant plants.
There are two opinions on the derivation of the genus name. The
one says that it is from the Greek ixos meaning mistletoe
(viscum), birdlime, referring to the viscous sap (Jackson); the
other says that Linnaeus derived the name from an old Greek name
for a plant noted for the variability of its flower colour (Lewis
1962). Since Ixia is a variable genus of many flower colours,
the latter explanation is more appropriate. In fact, in the late
1700's when the genus was first established and new plants were
being discovered in South Africa with specimens shipped to Europe,
many species that are today not considered part of the genus were
described in the genus Ixia, thus making it appear even more
variable to the botanists of the day than it actually is. The species
name viridiflora means green-flowered in Latin.
The common name green ixia or 'groenkalossie' in Afrikaans is also
derived from the green colour of the flowers. The name 'kalossie'
is a general name given to many species of Ixia and Lachenalia.
It is differentiated by a prefix denoting a distinguishing characteristic
of the plant e.g. the colour of the flower or habitat of the plant
i.e. 'groenkalossie' if the flowers are green, 'klipkalossie' if
the plant grows in a rocky habitat, etc. The word 'kalossie' is
derived from the Afrikaans 'kalotjie' (Eng.: calotte), a skull cap;
the bowl-shaped perianth of some of the ixias is reminiscent of
the shape of an old fashioned skull cap. Ixia viridiflora
has also been called the amethyst ixia, and the green-stained ixia,
although Lewis (1962) thinks that the plant illustrated by Curtis
and called the amethyst ixia is actually a hybrid with Ixia viridiflora
as one of the parents. Some other species in the genus e.g.
I. flexuosa and I. polystachya are called 'koringblommetjie'
or cornflower as they are frequently found growing in wheat lands
in the Cape. Other completely unrelated plants also share this common
name, e.g. Scabiosa africana and Lapeirousia corymbosa.
In the USA and Australia, ixias are also known as wand flowers or
African cornflowers or corn lilies.
Growing Ixia viridiflora
have been cultivated in Europe since the mid 1700's. They hybridize
quite readily, and today, Ixia hybrids are freely available
and grown all over the world. Getting material of the true species
is a bit more difficult and growing them is more challenging.
Ixia viridiflora although quick to flower from seed, is not
the easiest of the ixias to grow, as it is quick to rot in poorly
drained soil. The basic requirements for growing this ixia are:
sandy soil with good drainage, a sunny location, and a completely
dry, dormant period in summer.
Ixia viridiflora makes an excellent pot plant but is not
well suited to a permanent position in the garden, even in winter
rainfall areas. They are susceptible to fungal diseases, are eaten
by mole rats and porcupines, and need a completely dry summer. To
deal with this problem, one can plunge pots of Ixia viridiflora
into the garden during the growing and/or flowering period and remove
them during the summer dormant period.
Corms should be planted in autumn (April-May) while still dormant.
You will need a pot at least 30 cm in diameter. Place a layer of
stone chips over the drainage holes and fill three quarters of the
pot with a freely-draining soil mix, e.g. equal parts coarse river
sand and fine compost (leaf mould). Plant the corms in a 1 cm layer
of pure river sand and cover with a 1 cm layer of the soil mix.
Water thoroughly immediately after planting and place in a spot
that gets at least half-day sun. Once growth becomes visible, a
good drenching every ten days is recommended. Because Ixia viridiflora
is tall, it may need to be staked if your garden is windy. Inorganic
fertilizers should be avoided, particularly high nitrogen fertilizers,
but organic fertilizers can be used sparingly. When the leaves begin
to dry, stop watering altogether. The corms can be left in the pot,
provided it is stored in a cool, dry spot. It is advisable to lift
them every second year. This gives you the opportunity to clean
them, inspect them for disease and discard the badly damaged ones.
Although Ixia viridiflora corms do multiply by producing
offsets, the corms are relatively short-lived and constantly need
to be re-propagated from seed. Seed should be sown in autumn (April-May)
in a sunny spot, in well-drained medium at a depth of 3-5 mm. Sow
thinly and allow good ventilation, otherwise damping off may occur.
It is best to use a seed tray that is at least 10 cm deep, or raised
seedbeds. Keep the soil moist and germination should occur in three
to four weeks. Ixia viridiflora is a rapid grower, and can
produce its first flowers only seven months after germinating although
most seedlings will flower in their second season. It is best to
leave the seedlings undisturbed until after their second season.
Ixias in containers are susceptible to mealy bug infestation of
the corms. This is eventually fatal and should be treated with a
drench of chlorpyrifos. Likewise, during storage, it is best to
dust them with bexadust to keep the mealy bugs off. The foliage
and developing flower buds can also be attacked by aphids and red-spider
mite, but seldom severely enough to require an insecticide. The
corms are susceptible to attack by fungi causing rotting and can
be dusted with fungicides like 50:50 captab:iprodione prior to planting.
- DUNCAN, G. 1999. Ixias for pot and garden. Veld &
Flora 85: 78, 79.
- LEWIS, G.J. 1931. Ixia. Journal of the Botanical Society
of South Africa 17: 13-16.
- LEWIS, G.J. 1962. South African Iridaceae, the genus Ixia.
Journal of South African Botany 28: 45-195.
- GOLDBLATT, P., BERNHARDT, P. & MANNING, J.C. 2000. Adaptive
radiation of pollination mechanisms in Ixia (Iridaceae: Crocoideae).
Annals of the Missouri Botanical Garden 87: 564-777.
- GOLDBLATT, P., BERNHARDT, P. & MANNING, J.C. 1998. Pollination
of petaloid geophytes by monkey beetles (Scarabaeidae: Rutelinae:
Hopliini) in southern Africa. Annals of the Missouri Botanical
Garden 85: 215-230.
- SMITH, C.A. 1966. Common names of South African plants.
Memoirs of the Botanical Survey of South Africa No. 35. Government
- JACKSON, W.P.U. 1990. Origins and meanings of names of South
African plant genera. University of Cape Town.
- HILTON-TAYLOR, C. 1996. Red Data List of southern African
plants. Strelitzia 4. National Botanical Institute, Pretoria.
- CURTIS, W 1804. Curtis's Botanical Magazine.Series 1.
Vol. 21 plate 789.
Author: Alice Notten
Kirstenbosch National Botanical Garden