About the genus
Agave occur naturally in the New World, principally in Mexico, but as far north as Utah, in the northern part of South America and on the Caribbean islands. They have become naturalised in many parts of the world, notably around the Mediterranean. There are around 250 species plus many cultivated hybrids and variegates. Many make stunning architectural plants for the patio, conservatory, windowsill or greenhouse. They usually have fierce spines at the leaf tips or teeth along the leaf edges. Often the leaves are striped or are attractively marked with bud imprints.
Most Agave can take many years to become mature enough to flower but when they do, they produce impressive telegraph-pole-like spikes several metres tall. The flowering rosette always dies but often offsets are produced which can be removed and grown on.
Many species (not those from the Caribbean) are frost-hardy and if kept completely dry they can survive in an unheated greenhouse or a cold frame. On the patio they are best grown in either glazed or unglazed containers and must be brought indoors before any frosts occur.
How to grow them
Agave are generally easy to grow and are mostly pest-free. Their usual growing season in the UK is from April to September, when they can be watered generously on a weekly basis. Dilute fertiliser can be given once a fortnight. Free-draining compost is recommended. If the plants are kept in a green-house that is maintained just frost-free in the winter then the plants should be kept dry during this period. If grown on a windowsill, or in a heated conservatory with higher winter temperatures, they can be given modest amounts of water in the winter.
They will benefit from good light levels wherever they are grown. However, in a greenhouse or conservatory some shading could be needed to prevent scorching. Indoors on a windowsill a south-facing position is best and they will certainly suffer in dark corners of living rooms.
Removal of dead leaves is a problem specific to growing Agave. Old leaves naturally die and dry up at the base of rosettes. These can be very tough and require careful removal by cutting away with secateurs or large, strong sharp scissors.
Propagation is either by removal of offsets which can be treated as cuttings and potted up separately or by seed raising.
Recommended species
A. attenuata: soft grey-green leaves without spines or teeth; fast grower but does need winter warmth.
A. filifera: fibres peel off the leaf edges.
A. lophantha: striped leaves with prominent teeth.
A. parryi: attractive grey-green leaves with contrasting dark brown teeth and spines.
A. striata and A. stricta: porcupine-like with many long, narrow leaves and sharp spines.
A. victoriae-reginae and A. nickelsiae: slow-growing with attractively marked chunky leaves.
Text and photos: Colin C Walker
No part of this article may be reproduced without permission. Copyright BCSS and the Author 2019