Green Thoughts: Spiky fellows

Of these, the yucca, a native of American hot de­sert regions, is the best known. A perennial shrub from the agavaceae subfamily, it has large rosettes of stiff, sword-shaped leaves which often terminate in vicious spikes. A deterrent to would-be animal brows­ers.

It is widely grown in the tropics as an ornamental plant, and produces large, erect panicles of white or cream bell-shaped flowers. After blooming, the main clump dies. Y. filamentosa is a popular bushy form: cultivars “Bright Edge” and the larger “Golden Sword” have yellow edged foliage.

A. americana, a substantial plant from the re­lated family of agaves, has a huge rosette of broad, bright green leaves up to two metres long with sharp serrated edges. It is popular in Thailand where it is reliably hardy.

All agaves and yuccas possess robust roots. In tropical gardens they require little care and atten­tion. Both are shrubs for xeric conditions, perfectly equipped to store occasional bursts of rainwater chan­nelled downwards from the waxy leaves. They are so efficient at water retention that consistent overdoses of monsoon rain may cause their demise. Sodden roots will rot away. They appreciate hot sun, good drainage, and will tolerate poor, sandy soil. Grow from seed, root cuttings or suckers.

Sansevieria trifasciata, or mother-in-law’s tongue, is a very distinctive member of the agave family; in fact, it is usually treated as a separate species. It has the typical agave’s rigid, spinous leaves, but little else in common. From West Africa, not America, the upright patterned rosette of succulent leaves, some­what cactus-like, are dark green usually with yellow edging. They are often twisted and banded with grey-green horizontal stripes.

It is popular as a house plant because it will with­stand a range of conditions, including low light, dry air and capricious watering. It seldom needs repotting. It is used outdoors as a low-maintenance addition to beds in order to provide variety in formal plantings.

In Asia, the pandanus is usually associated with the screw pine or screw palm of beach dunes, familiar to all beach bums with its long, stilt-like roots project­ing from the sand and huge, swathe-like leaves. Much used for roofing and for woven mats, the fragrant leaves are also pressed into service as a food flavour­ing reminiscent of vanilla, and as an aromatic in steam rooms and saunas.

Its relative P. pygmaeus is quite different; a dwarf form with bright green and yellow variegated foliage similar to variegated spider grass, and a bushy habit which make it invaluable to the gardener as a low-growing plant for borders. It needs little maintenance and will put up with lowish levels of light and humid­ity, qualities which also make it welcome as a house plant. The narrow leaf edges are serrated and sharp, so care needs to be taken when dividing clumps. It is also very disease resistant.

Patrick has been writing for thirteen years about gardening in Phuket and allied topics. If you have horticultural or environmental concerns, please con­tact him at drpaccampbell@gmail.com. Many of his earlier creative and academic publications can be found at Wordpress: Green Galoshes.

Patrick will shortly be publishing ‘The Tropic Gardener’, an indispensable guide to Southeast Asia’s flowering plants, based on his experience of gardening in Phuket.