Colourful ground covers among Australian plants

Press, 28 March 1980, Page 10

Colourful ground covers among Australian plants

GARDENING

By

M.Lusty

Colourful trees and shrubs indigenous to Australia are great and varied in number, but you do not often get much publicity surrounding ground covers. Even in the country of origin, where landscaping with plants has really caught on only over the last decade or two, their potential is only just being fully exploited. One of the most beautiful flowering semiprostrate plants one could wish to grow . is the Sturt pea, Clianthus formosus. Unfortunately, it si only half hardy

and along with its special requirements it is doubtful if it could be recommended for general planting outdoors under local conditions. However, as a trailing pot plant it has great possibilities — particularly as it will flower in its first year. Not so many years ago a fine specimen flourished in the simulated desert section of the Cacti House in the Christchurch Botanic Gardens. The Sturt Pea is in* digenous to Australia, having first been discovered in the north-west

of Western Australia in 1699. It is found growing along the North West Coast and into the desert, in the Nullarbor Plain and also in Northern Territory, New South Wales and South Australia. Some variation in colour of flowers exists but perhaps those which are a brilliant scarlet with a shiny black central portion called the “boss” are the most spectacular. Less prominent red flowered forms verging to pink, and without the conspicuous black boss, are not uncommon; near white and pure white varieties occur in one area near Kalgoorlie. Growth springs to life after first heavy rains following the winter and is fairly rapid as is to be expected from a plant which has to make the most of conditions conducive to development while they last. Although it is a perennial of limited life expectancy, it is widely regarded as an annual in cultivation. Pollination is carried out by certain birds in the plant’s natural habitats and this accounts for the failure of flowers to set seed unless assisted. Seed is available from at least one New Zealand commercial specialist seed firm in the North Island and from various sources in Australia including some of tlie various State Societies for Growing Australian Plants. As will be fully appreciated, a desert plant requires the best of drainage if it is to survive. As it develops a good sized tap root a good depth of suitable soil, tending on the sandy loam, is best. And because of its tendency to produce a long root it definitely resents disturbances: if it cannot be grown in situ then transplanting should be done only while a seedling and then with utmost care and the minimum of delay. The seed coat is hard

and requires breaking to hasten germination. This can be done by nicking the seed with a file or soaking it in hot water. A.method which induces rapid germination is to boil the seed for one minute and then allow it to cool for 48 hours following which it should be

sown straight away. The seed can be sown at any time between September and December. Peat pots provide the ideal means for starting plants into growth as they can be transplanted without problems into their final situation. A sharp sand and vermiculite medium can be used in the pots. Watering should be very carefully regulated with the initial aitn to keeping moisture just below the top. Later on, as the plants grow, moisture is only necessary down at root level and should be minimal once flowering commences. A surface mulch of grit is ideal and water should be given from the sides and not from above when necessary. Grow in full sun at all times. Flowering may occur within three months of seed sowing and can continue with a succession of raceme borne blooms for weeks if not months thereafter as is proving the case with the specimen illustrated here. Potted plants can be cut back as the winter draws near and kept inside until the warmer weather prevails again. It should be noted that Sturt Pea is also well known as Sturt’s Desert Pea, Desert Pea and Glory Pea, and that the botanical

synonym of Clianthus dampieri is also still in use. This , name Was originally bestowed on the plant in honour of its discoverer. William Dampier; an explorer. Captain Charles Sturt, compatriot, and likewise explorer, is remembered by the common name. Apart from raising plants- from seed, specimens can also be grown from cuttings and by means of grafting. The grafting technique has not been seen or tried and would require considerable skill as it involves utilising the plant when in the cotyledon or primary leaf stage. The purpose behind grafting is to produce a longer lived plant. Colutea arborescens, Bladder senna, a vigorous growing shrub which belongs to the same family as the Sturt Pea, is used as the root stock.