Giant Dioon

Giant Dioon (Dioon spinulosum) is a sculptural cycad with long arching fronds, growing with great patience to about 2.5m tall and 2m wide in an Australian garden. In its Central American habitat it can build a 12m trunk over centuries; in your lifetime it behaves as a refined architectural feature that never outgrows its place. Drought tolerant, salt tolerant and close to zero maintenance, it is as reliable as statement plants get.

Why you'll love it

• Living sculpture. The symmetrical crown of arching fronds looks composed from every angle, doing the work of an art piece in a courtyard or entry.
• It keeps its scale. Extremely slow growth means the plant you position today still fits that spot in twenty years, with no pruning battles.
• Tough beyond its looks. Heat, drought, salt spray and coastal wind are all within its range once established.
• Perfect in a pot. Slow growth and a compact root system make it a long term container plant for terraces and paved courtyards.

Where it works best

Feature planting. Give it a clear position where the symmetry can be seen: beside an entry, centred in a gravel bed or against a plain rendered wall.

Pots and containers. A wide, stable pot with a free draining mix suits it for many years.

Poolside and rockeries. It drops little, tolerates reflected heat and looks at home among stone, which is why it appears in so many designer pool landscapes.

Growing Giant Dioon in Australia

Position and climate. Full sun to light shade in tropical, subtropical and warm temperate gardens. It takes light frost only: in colder districts grow it in a container and move it under cover through winter.

Soil. Free draining, always. Sandy and gravelly soils are ideal; on clay, plant on a raised mound or keep it potted. Waterlogging is the one reliable way to kill a cycad.

Water and feed. Water every week or two through the first summer, then only in long dry spells. A half strength slow release feed in spring is ample. Overwatering does far more harm than neglect.

Pruning. Remove spent lower fronds at the trunk as they age. The leaflets carry small spines, so wear gloves and long sleeves for the job.

What to expect when it arrives

We sell Giant Dioon in a 200mm pot, supplied as a pack of 6 for repeated designer plantings, and as a single established 400mm plant. Because cycads grow so slowly, the 400mm size represents years of nursery time and arrives with genuine presence; the 200mm plants are younger and suit buyers planting for the long game. Expect little visible change for months at a time: cycads push new fronds in occasional flushes, usually in warm weather.

Plants are packed to travel upright and delivered Australia wide, with delivery from $29.95. Advanced and large stock is freighted at cost. Every plant is covered by our 30 day healthy plant guarantee.

Plant care guides and related reading

• Low maintenance plants for architectural gardens
• Browse architectural and designer plants
• Explore exotic and rare plants
• Plants for poolside gardens

Common questions

How fast does it grow?

Very slowly, and that is the point. Expect a flush or two of new fronds a year in warm climates and a plant that holds its size and shape for decades. Buy the largest size you can afford, because you cannot hurry a cycad.

Is it safe around pets?

No. Like all cycads, every part of the plant is highly toxic to cats and dogs if chewed. Position it out of reach of pets that browse plants, or choose something from our pet safe range instead.

Will it survive frost?

Light frost only. Foliage burns in a hard freeze and repeated frosts will kill it. In frosty districts keep it potted and move it under a verandah or a bright window over winter.

How long can it stay in a pot?

Many years. Slow growth means repotting only every four to five years, into a pot one size larger with a coarse free draining mix. It is one of the easiest feature plants to keep in a container permanently.