PENROCK SEEDS AND PLANTS NEWSLETTER MARCH AND APRIL 2008
 

AMOCHARIS CORANICA IN THE NORTH WEST AND LIMPOPO PROVINCES.



Amocharis coranica in full flower in mid-October 2007 in Acacia woodland south of the Borakalalo Nature Reserve, North West Province.




Amocharis coranica sometimes grows together with other plants in this case Bulbine abyssinica. These plants were photographed near the Borakalalo Nature Reserve in mid-October 2007.



Amocharis coranica sometimes grows in deep loamy soil adjacent to dolomite rocks. This plant was photographed close to Assen in the North West Province during October 2007.



Amocharis coranica in full flower near Assen, North West Province about 10 days after good soaking rains. The grass cover has just emerged and the red flowers are, under these conditions, conspicuous to pollinators.



The typical distribution of Amocharis coranica in their habitat near Assen in the North West Province. The plants here grow in heavy loamy dolomite derived soil.



Flat arid Acacia savannah west of Northam, the characteristic habitat of Amocharis coranica in the western corner of Limpopo Province. The Witfontein-rand, a range of mountains that runs south west from Thabazimbi is visible in the far distance, as a pale ribbon that divides the land from the sky.

SUMMARY

Amocharis coranica is a widespread species in South Africa occurring over much of the summer rainfall interior particularly in rather arid places with deep loamy soil. There are large colonies of this species in the north eastern parts of the North West Province and in the adjacent western section of the Limpopo Province.

The success of this species lies in its huge long lived drought resistant bulbs and their ability to flower quickly and set seed after the first substantial summer rains. The newsletter focuses on these aspects and also the requirements of the bulbs in cultivation.

NEWSLETTER.
Amocharis coranica is well represented in the arid acacia savannah north of Brits in the North West Province. This area is used for pastoralism by the local people who live in villages and graze their livestock, mainly cattle, in the surrounding countryside. A. coranica is found mostly in places with deep reddish loamy soils. The bulbs grow chiefly in sunny places but also in the light shade provided by various deciduous acacia trees which are very numerous in the Amocharis habitat.

The bulbs occur singly or in small groups of 2 – 6 plants widely scattered over the habitat. They flower within about 10 days after the first good summer rains which generally fall between mid October and mid November. If the rains are late the flowering season is delayed by a few weeks. The area is subject to droughts and in dry years the bulbs may not receive enough rain to break dormancy. As a general rule they do not flower after the middle of January even if good rains fall then.

October 2007 was characterised by abundant heavy rains in the habitat and one of the best flowering seasons on record. In late October large numbers of bulbs were in magnificent flower with their huge umbels of pinkish red flowers visible far and wide, amongst the short fresh green grass. Many of the largest bulbs produced two umbels of flowers. This habit seems to be restricted to years of abundant rainfall.

A. coranica is very well represented in parts of the western section of Limpopo Province particularly around Amandelbult, Northam and Dwaalboom. This area is used for cattle ranching and game farming. It is also rich in minerals and there are several large chrome and platinum mines. The Amocharis are found in arid acacia thornveld and are also partial in this region to heavy deep loamy soil. A good proportion of habitat has been destroyed through agriculture and mining but this is of little consequence overall as the species is well represented where it occurs.

There are several mountain ranges in the western corner of Limpopo Province such as the Swartwitpensbokfonteinberg near Northam and the Witfonteinrand west of Thabazimbi. The Amocharis avoid these mountains and the adjacent rocky hills as the soils are too shallow for the development of their large bulbs. They do occur however in loamy soils above sheets of dolomite. These places tend to retain moisture after rainfall and are conducive to the survival and development of young bulbs.

The Amocharis flower with the onset of the first good summer rains as they do in the North West Province. The bulbs rarely flower during dry years though they may send up leaves after a light rainshower.

FLOWERING AND SEEDING IN HABITAT.
During years of abundant early summer rainfall such as October and November 2007 mass flowering takes place. This affords ideal opportunities for the photography of these spectacular plants. The large numbers of flowers blooming simultaneously in the general area attract good numbers of pollinators. This ensures a good seed set about 5 – 6 weeks later.

The Amocharis produce very large amounts of small seeds. The majority of these shrivel in the sun if December is a dry month. Some of them are distributed by runoff after rainfall and land in niches where they are protected from intense sunlight. These niches are typically under the leaves of the adult plants, amongst tufts of grass or amongst dead twigs and leaves that have accumulated on the surface of the soil. The seeds send out roots very quickly and a young bulb has usually formed within a few weeks. The initial leaf is very thin and grass-like. This cuts down water loss via transpiration to a bare minimum and assists the young plants survive through the heat of summer.

There is a thick cover of grasses and annual herbs in the Amocharis habitat during years of good rainfall. This provides the seedlings with filtered sunlight which is beneficial for their development in the first growing season.

LONGEVITY OF THE BULBS.
Large A. coranica bulbs may be 20 cms wide and 20 cms tall weighing several kilograms. These huge bulbs are encased in layers of bulb tunics that are often up to 2 cms thick. These bulbs are likely to be very old, possibly more than 100 years. Little research has been done on this interesting subject. The success of the species in rather arid habitats, subject to frequent and prolonged droughts, is certainly attributable to the longevity of the bulbs.

The Amocharis take about 8 – 10 years to reach flowering size in habitat and probably longer than this for young bulbs that begin their lives in dry climatic cycles.

CULTIVATION.
A. coranica is best cultivated in large deep containers. These should ideally be in the region of 50 – 60 cms wide and at least 40 cms deep. The pots should be kept in strong direct sunlight for at least the full duration of a morning or afternoon. In summer rainfall areas they re best left out in the rain. They usually produce leaves and flower soon after the first good soaking rains of the summer.

During hot dry weather the plants lose their leaves if they are not watered. Leaf growth is resumed again a few days after receiving rainfall or water. The plants should be kept completely dry during their winter resting period which in the
Southern Hemisphere is from April to September.

The bulbs thrive in most soil mixes when grown in containers and they are also good subjects for sunny rockeries or sunny garden beds that are not forked over. Care also needs to be taken to ensure that the place where the plants are grown is not watered during the winter dormancy period.

A. coranica is readily grown from seeds. These should be lightly and evenly scattered across the surface of the growing medium soon after they start to sprout roots. The developing bulbs need to be grown in large deep containers in order to gain size rapidly. The seeds are best sown in these big containers. This avoids disturbing and replanting young bulbs which is necessary when the seeds are sown on the surface of the soil in shallow propagation trays.

Photographs by Connall Oosterbroek