Oleanders

How to choose oleanders

Size is the first decision. Tall oleanders reach 3m to 4m high and nearly as wide, and make a dense evergreen screen. Splendens Double Pink Oleander is the classic, with large double pink flowers, and Madonna Grandiflorum Oleander is the white counterpart. Rosebay is a red-flowered form.

Dwarf oleanders stay around 1m to 1.5m and suit low hedges, median strips and large tubs. Oleander Dwarf Pink and Dwarf Apricot Oleander are the two to compare, and they look good planted together. Variegated Oleander has cream-edged leaves that carry interest when the shrub is not in flower.

Where oleanders work

Oleanders grow across most of Australia, from the tropics to Melbourne, Adelaide and Perth, and inland. They want full sun; in shade they grow leggy and flower poorly. They tolerate drought, heat reflected off paving and walls, salt-laden wind, and sandy, clay or alkaline soil. Established plants take frosts to about minus 5 degrees, with some tip burn, but struggle where winters are colder than that.

Safety comes first with this plant. All parts of oleander are poisonous to people, pets and livestock if eaten, including leaves, flowers, sap and dried clippings. Do not plant it beside paddocks, in play areas, or where children or animals are likely to chew it. For related choices, see the drought tolerant plants, coastal and salt tolerant plants and the wider hedging and screening range.

Planting and spacing

For a screen, plant tall varieties 1.2m to 1.5m apart. For a low hedge of dwarf oleanders, 60cm to 80cm apart is right. As a single specimen, allow a tall variety at least 2.5m of width. Dig a hole twice the width of the pot and no deeper, set the plant at the level it grew, backfill with the original soil and water in thoroughly. Oleanders do not need rich soil. In pots, use a tub of at least 40cm for a dwarf form and a free-draining mix.

Care basics

Water weekly through the first summer. After that, oleanders survive on rainfall in most districts, though a deep soak in long dry spells improves flowering. Feed once in spring with a general slow release fertiliser. Prune after the main flush of flowers, in late summer or autumn, cutting back by up to a third to keep the shrub dense; old, bare plants can be cut hard and will reshoot. Remove seed pods to prevent unwanted seedlings.

Always wear gloves and long sleeves when pruning, as the sap can irritate skin and eyes, and wash hands and tools afterwards. Never burn the prunings, because the smoke is toxic, and keep them away from stock and out of compost used on food gardens. Scale and aphids appear occasionally and are easily managed with horticultural oil.

Common questions

Is oleander poisonous?

Yes. All parts of the plant are poisonous to people, pets and livestock if eaten, and the sap can irritate skin. Wear gloves when handling it and never burn the clippings.

How tall do oleanders grow?

Tall varieties reach 3m to 4m. Dwarf forms stay around 1m to 1.5m and can be kept lower with pruning.

Do oleanders grow near the coast?

Yes. They tolerate salt wind and sandy soil, and are widely used in seaside gardens.

When do oleanders flower?

From late spring through summer and into autumn, with the heaviest display in the hottest months.