Greenspace: Aloe beyond vera

Some years ago I owned up to being a cactophile in this column – while perhaps more technically correct, at that time, I couldn’t quite come out as a succulentophile. Cacti are, of course, a particularly rich and showy group of succulents and some believe they deserve to be separately mentioned. Hence we have ‘cactus & succulent’ societies where ‘succulent’ would suffice. In mid-winter, most cactus growers are frustrated with low light, cold and damp that sees cacti sulking out of doors. Even under glass there are challenges that make growers reluctant to provide plants for the show bench. However, one group of succulents – the aloes – choose this time and these conditions to flower spectacularly. Aloe is a genus of more than 500 species from Africa and the Arabian Peninsula – the most famous is Aloe vera – commonly utilised in skin products, shampoos and antibiotic washes, the therapeutic value of Aloe vera remains disputed with a range of contradictory evidence. It’s generally assumed that, while now unknown in the wild, A. vera was endemic in the Arabian peninsula – a closely related species, A. officinarum, is still found in Yemen. From here, A. vera was collected and sold onto a trade route connecting Europe and the far east (the Queen of Sheba effectively taxed such caravans passing through her territory). Another, less compelling, view suggests A. vera was native to the woodlands of the Sahara – now lost to desertification. A long history of cultivation (A. vera was apparently cultivated in ancient Egypt) sees A. vera unable to reproduce by seed, although Aloe vera is still widely naturalised out of cultivation. However much you might love Aloe vera preparations, the plant itself is less choice in form or flower than many of its genus – grown for utility rather than ornament. With more than 500 species there are a great many life forms to choose from – trees of over 15 metres, such as Aloe barberae from South Africa (also known as A. bainesi) and A.eminens, an endangered species from Somalia, shrubs, climbers, rosettes and bulbs. Molecular taxonomists have put the aloes into the Australian grass-tree or yakka family, the Xanthorrhoeaceae – a curious affiliation. The form and structure of aloes are rich enough to make them worth growing regardless of any flowers. One of my favourites is A. polyphylla – an endangered species from Lesotho with beautiful, almost Paris-green leaves arranged in elegant clockwise or anticlockwise spirals (an explanation of the golden ratio and the Fibonacci series that generate this arrangement’s a future topic). Tissue culture has made this species reasonably available in nurseries. The richness of aloes has attracted some remarkable botanical collectors to the field. Professor Len Newton has spent much of his career at Kumasi University in Ghana and at Kenyatta University in Nairobi chasing aloes all over their range, John Lavranos has a 50-year history in succulent plant collecting and Susan Carter Holmes has worked with euphorbias and aloes at Kew Gardens – together with Colin Walker they’ve published Aloes: the definitive guide through Kew Gardens. I met collector Tom McCoy with Len Newton in Nairobi years ago and was impressed by Tom’s lunacy in chasing aloe species between Eritrean and Ethiopian lines during the war heedless of the conflict. I preferred the pace of a more recent report from the Cactus & Succulent Journal of the American society where Tom and John Lavranos described Aloe barbarajeppeae. The editor wryly observes: “Tom McCoy braved below freezing temperatures waiting for the sun to rise on a lonely hill in South Africa so he could capture the first rays of dawn’s light on this exciting new species of aloe … That said, he confided in me that upon reaching a civilized, little highland town later in the day, he rewarded himself with a hearty brunch of prime cut South African bacon, crepe-wrapped bananas topped with cinnamon sugar and a fine pot of locally grown coffee. Ah, the life and perils a plant explorer must endure.” Aloe flowering can be extravagant and joyous – showy and nectar-filled flowers attract birds as pollinators and present an exuberant intrusion into winter in bright oranges, reds and yellows, paler shades and even whites and creams. Len Newton notes that the joy isn’t always shared – while the flowering of aloes is important in apiculture in South Africa the nectar and pollen of some species can affect the behaviour of bees – making them vicious! While my interest is largely in species there are some superb hybrid cultivars. You can see species including young quiver trees, Aloe dichotoma (from which quivers are indeed made), old tree aloes, A. barberae and fine fan aloes, A. plicatilis in the Cactus Garden as well as some of the outrageous hybrid showoffs near the old morgue in the south-western corner of the new wetland in Adelaide Botanic Gardens. A visit to the Terrace beds at Wittunga Botanic Garden is also well worthwhile. So, as aloes are generally easy to grow, incredibly drought-tolerant and great structural plants with brilliant flowers, you need to find out more. While there’s no specialist aloe society in Australia, it’s worth joining the Cactus & Succulent Society of South Australia (CSSSA) that meets on the third Friday of most months at Western Youth Centre, 79 Marion Road, Cowandilla (csssa.org.au). Again, while not specifically focussed on aloes, some of Attila Kapitany’s books have great information for Australia (australiansucculents.com). To source the outrageous hybrids bred by Leo Thamm at Sunbird Aloes near Johannesburg, visit Aloe-Aloe Horticulture’s collection (aloe-aloe.com.au). Stephen Forbes, Director, Botanic Gardens of Adelaide @StephenJForbes