Triangle Palm Dypsis decaryi

Triangle palm stacks its leaf bases in three vertical ranks, so the base of the crown forms a genuine triangle in cross-section, and that geometry is what people buy it for. The fronds are stiff, blue-grey and strongly arching, with drooping leaflet tips and fine thread-like strands hanging from them. It comes from dry forest in southern Madagascar. Use it as a feature you can walk right up to, in a courtyard, a gravel bed or a loose group where each palm still reads as an individual.

Dry-country roots and wet feet

It takes part shade to full sun, moderate watering through summer, and grows at a moderate pace, taking several years to show clean trunk. It tolerates more sun and more dryness than the other Dypsis in this batch once it is established, and it wants frost-free conditions and open ground. The failure mode is drainage. This palm comes from a seasonally dry forest, and roots that sit in cold wet clay, in a lawn that is irrigated all winter, or in a bed at the bottom of a slope will rot, after which the crown declines and a solitary palm has nothing in reserve. Plant it high, mound the bed if the soil is heavy, add coarse material to the backfill, and cut back irrigation over the cool months. Give it space on every side too, because burying the base in a dense border hides the triangle, which is the thing you are paying for.

Geometry against fur and plume

Set against teddy bear palm, the same genus goes in the opposite direction: teddy bear wants warmth, moisture and shelter and gives you a furred crownshaft and a soft pendulous crown, while triangle palm is stiff, blue-toned, drier in its habits and architectural rather than tropical. Against foxtail palm, both take sun, but foxtail wants heat and steady moisture and reads as a soft plume, where this one holds hard lines and copes with a drier bed. Choose triangle palm for a modern or gravel-mulched garden, and foxtail for a poolside tropical scheme. It is also the sensible pick for an inland warm-climate block where summer watering is limited, since the other two will look thirsty long before this one does. Specimen sizes sit in the 200L and larger range.

What to cut and what to leave alone

Remove fronds only once they are fully brown, cutting the stalk back close to the leaf base, and do it in the warm months. Leave the old leaf bases on the trunk alone: they are what build the three-ranked pattern, and stripping them back to make the trunk look clean removes the feature. Do not shave or trim the thread-like filaments either. Feed in early spring and again in mid summer with a controlled release palm fertiliser carrying potassium and magnesium, spread over the root zone. Use a coarse gravel or bark mulch rather than a fine, moisture-holding one, and keep it clear of the trunk.

Choosing a size

This plant is available in 5 sizes, from 400mm up to 500L, priced from $229.00 to $4949.00 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. Every size here is established stock rather than a starter plant, so this line is intended for immediate effect rather than for growing on. Not sure which to choose? Read our guide to when to plant in Australia.