Topic of the week

African Bulbs
Mon, 25 Oct 2004 00:56:42 PDT
Ammocharis coranica - I have been observing it in its natural habitats and growing it for many years.  I would like to share with you all my experiences with this beautiful bulb with which I have had a special relationship.

Its common name in South Africa is Karoo lily.  The Karoo is the vast elevated dry central plain.  Ammocharis coranica occurs throughout the Karoo and its range extends into the eastern grassland of the summer rainfall area. Although it is very widespread and common, it occurs in isolated populations in areas that suit it.  It generally occurs at altitudes between 700 and 1500 metres on flats or in depressions which are seasonally wet, although its habitat is characterised by lengthy dry periods and severe droughts.  It often occurs in bushy areas - typically in Acacia savannah, but is equally at home in short grassland.  It often occurs in rocky soil but is just as happy in clay soils.  The populations are characterised by vast numbers of plants packed closely together - sometimes over an area of a hectare or more in extent.

I have seen it as far west as Willowmore where the average annual rainfall does not exceed 350mm, but here it is usually confined to depressions where storm water accumulates.  In the wetter eastern regions it can occur in a variety of habitats, but always in flatter country and never on steep and well drained slopes.  It can tolerate frosts to - 8C in the winter when it it is completely dormant.

Leaf growth and flowering are entirely dependant on the rainfall.  While the normal growth cycle starts in spring with flowering from October to early December, this is entirely dependant on rainfall and it is capable of remaining dormant until rain falls.  It only flowers when conditions are ideal - populations often skipping a season if conditions are not right.  I am at loss to know what stimulates flowering.  Fire is certainly a factor in the grassland, provided it is followed by good rain, resulting in truly spectacular displays of massed flowers.  However despite spring fires and early rains, some populations simply fail to flower in that season.  On the other hand they often flower without the stimulation of fire, so it is by no means essential. 

They produce copious amounts of seed which germinate readily when conditions are favourable (which is very seldom in nature).   However, when this does happen very thick stands of plants result.  Ammocharis is not affected to any large extent by grazing livestock - its leaves must be fairly unpalatable.  Flowers and seed capsules are more readily eaten by sheep and goats.  Its main natural enemy is the Amaryllis worm, Brithys crini pancratii, which has devastating effects when there are severe outbreaks, which are very frequent in the wild.  They will eat all parts of the plant, favouring the seed capsules, but sometimes boring right into the bulbs.  Ammocharis are the most susceptable amaryillid species to this pest and in nurseries they are always the first plants to be infested.  They are therefore very useful, especially in Clivia nurseries, as indicators of a potential infestation (The next best menu item for the Amaryllis worm seems to be Crinum moorei!). 

Ammocharis are rather shy to flower in captivity.  It is easy to propagate from seed but is slow growing and takes a good number of years to mature.   It is becoming popular as a landscaping subject in indigenous gardens in South Africa because it is so hardy,  the foliage is attractive and the flowers are strongly scented. There is not much variation in the colour or shape of the flower heads.  In all my years of exploring natural populations I have seen only one pure white flower. 

I have posted some pictures on the wicki 

1.  Ammocharis coranica floweringafter fire in grassland in the Cathcart District
2.  Ammocharis in fruit in the Willowmore district of the Karoo
3.  Ammocharis coranica growing in association with Nerine huttoniae in stony Karoo     flats - a habitat they share. 

These and many other images can be obtained from me on a CD I have compiled of the the Wild Bulbs of the Eastern Cape.  This CD has images in the natural habitat of most of the bulbs that occur  in this region as well as a great deal of  additional information in text files.  Please contact me for details. 

Cameron McMaster
African Bulbs
PO Box 26, Napier 7270
Tel/Fax: 028 423 3651

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