Carissa grandiflora 'Green Carpet'
My books on gardening in South Africa are kept on the top shelf of the bookcase which is best not navigated during the cocktail hour early evening, a time usually devoted to checking plant facts of one sort or another.
I like the gardening books written by Una van der Spuy, who sadly passed away last year just shy of her 100th birthday, and in her book on gardening with ground covers she gives some interesting facts on the dwarf forms of Carissa, a South African shrub which is grown in warm coastal gardens in many parts of the world.
She refers to three cultivars 'Green Carpet', which has small leaves on a plant 60cm in height and a metre across, 'Horizontalis' which has trailing stems of densely arranged leaves and 'Prostrata' which produces more side than top growth and spreads across a metre. All were developed in the United States, possibly during the mid 1970's as Una refers to them as 'recent' at the time of publication of this book.
Although the Carissa pictured here came labelled as 'Green Carpet' it has spread across an embankment by about 3 metres as well as sending up vertical branches to about a metre or more.The vertical branches can be easily pruned off to keep it low and spreading, though, as it is armed with three corned thorns just under the foliage, it has formed an impenetrable barrier and any 'under-gardener' given the task of maintaining it is apt to complain about this task.
The white star shaped flowers and the edible plum shaped red fruit which follow seem to occur throughout the year with the main flush during spring and summer.
I propagate it from semi hardwood cuttings taken during the warm months but cuttings may be slow to strike and the resulting plants are also slow to grow during their first year. Once in the ground the plant takes off and requires little additional water or fertilizer once established.
Carissa is tolerant of salt spray in coastal gardens and light frost.
To read more on the horticultural life of Una van der Spuy click on the following link:Una van der Spuy - Rhodes University
2017 update: I have limited stock of this plant.