Twin Flowered Agave Agave geminiflora

Agave geminiflora carries hundreds of narrow dark green leaves in a dense hemisphere, each one flexible rather than rigid, with fine white threads curling off the margins on younger plants. There are no hooked teeth along the edges to snag skin or clothing, which is unusual in this genus and the reason it can sit right beside a path, a seat or a driveway. It is grown as a symmetrical accent: in pots, repeated through gravel and dry garden beds, or planted in a group under an existing tree.

Growing geminiflora, and the catch to know first

Full sun, sharp drainage, not much else. It handles heat, reflected warmth off paving and salt laden coastal air without complaint, and once established it runs on rainfall in most of the country. In a pot use a cactus and succulent mix with extra coarse sand or perlite, and keep the pot off a saucer. In the ground on clay, plant high on a mound. Space plants so the rosettes do not touch, because a leaf ball growing into its neighbour loses its symmetry. The failure particular to this one is the density of the ball itself. Hundreds of fine leaves packed that tightly catch fallen leaf litter, bark and blown debris down in the centre, that pad stays wet for days after rain, and the crown rots from the inside while the outside of the rosette still looks sound. Clear the centre out each autumn with a blower or by hand, and do not plant it under a deciduous tree or a gutter drip line. The second thing to know before you buy is not a growing problem at all. This species is monocarpic. It flowers once, after many years, then dies, and unlike most agaves people plant it rarely throws pups, so there is no replacement waiting at the base. Buy it as a long lived feature, not a permanent one.

Why you would pick this over Blue Glow

Agave Blue Glow is the direct comparison, and the deciding factor is usually the position. Blue Glow has a firm terminal spine and has to be set back from anywhere people brush past; geminiflora is soft enough to plant against a path edge. Blue Glow is blue green, broad leaved and reads as a piece of geometry from a distance. Geminiflora is dark green, fine textured and reads as a soft ball, closer to a grass than a cactus. Blue Glow is monocarpic too, as every agave is, but it flowers so seldom in cultivation that it is the safer choice where a pot has to hold the same plant for a decade. Culture is close enough that the two share a bed without arguing over water. If you want scale instead, Aloe barberae is the tree in this group. All three sit under low maintenance.

Grooming a rosette that has to stay round

Pruning is limited to removing the dead. Cut browned lower leaves off flush with the base with a sharp knife or snips, working in spring, and do not shorten live leaves: a trimmed tip stays blunt and the ball loses its outline. Old plants build a small skirt of dry leaves that can be left or removed to taste. Feeding is minimal. Half strength controlled release fertiliser in early spring, once, is enough for a container plant, and in the ground you can leave it. Push it with nitrogen and water and you get long, floppy leaves that spoil the density, which is the only reason to grow it.

Choosing a size

This plant is available in 9 sizes, from 130mm up to 500mm, priced from $20.95 to $659.00 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. The smaller pots hold younger plants that cost less each and establish quickly, which suits hedges, screens and mass planting where the plant count adds up. The larger sizes carry several more years of growth on the farm and give height and presence straight away, which is what you want for a single feature position or a screen that cannot wait. Not sure which to choose? Read our guide to low water gardens.