BOMBAX ceiba (Red Silk Cotton Tree)

The Red Silk Cotton Tree (Bombax ceiba) is a big deciduous shade tree with one of the boldest flowering displays grown in Australia. It reaches around 15m tall and 10m wide, and before the new leaves appear the bare branches carry heavy cup shaped red flowers that birds work over all day. This is the ex ground option: field grown, advanced, years ahead of a potted tree.

Why you'll love it

• Red flowers on bare wood. The tree drops its leaves before it blooms, so nothing competes with the display and it reads from a long way off.
• Real shade, when you want it. A broad summer canopy cools the ground beneath, then winter leaf drop lets the sun back through.
• Fast for its size. A quick grower, and an ex ground specimen skips the slow early years.
• A bird tree. Nectar heavy flowers pull in honeyeaters and lorikeets through the flowering weeks.

Where it works best

Shade trees. This is an acreage and large block tree. Give it 10m of clear width, well away from the house, paving and services.

Feature planting. Set on its own in a lawn it becomes the focus of the property for several weeks a year.

Driveways and avenues. Spaced 12m to 15m apart along a long drive it makes a serious avenue, flowering as one line.

Growing the Red Silk Cotton Tree in Australia

Position and climate. Full sun and plenty of room. It suits tropical, subtropical and warm temperate gardens only, because it is frost tender. Cold inland districts, the tablelands and frosty southern gardens are out, and young trees want protection through their first winters even in mild areas.

Soil. Deep, well drained soil gives the best growth. It copes with most soil types but not ground that stays wet, so mound the planting site on heavy clay.

Water and feed. Water deeply through the first two summers while the roots spread, after which it is genuinely drought tolerant and takes heat and humidity without help. A complete slow release fertiliser in early spring is plenty.

Pruning. Very little is wanted: remove damaged wood and lift the lower branches for clearance while the tree is young. Young trunks carry stout conical prickles, so keep it clear of paths and play areas.

What to expect when it arrives

Ex ground stock is grown in open field, root pruned and lifted with a root ball rather than raised in a pot, and it is sold as a single advanced specimen rather than by pot size. Expect a heavy root ball needing machinery and clear vehicle access on the day. Plant in the cooler months, water it in hard, and stake it for two years.

It will look plain for a season while the roots recover, and flowering takes two to three years to settle into a rhythm. Advanced and large stock is freighted at cost, and plants are delivered Australia wide with a minimum order of $300 before delivery. Every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• Browse the full ex ground tree range
• Choosing a canopy tree for shade
• Compare other flowering trees
• Advanced trees for immediate impact

Common questions

How much room does it need?

Around 15m tall and 10m wide, so allow at least 10m of clear width. It is not a courtyard tree and should sit well clear of buildings, pipes and paving.

Will it grow in a cool climate?

No. Being frost tender it needs a warm frost free site, which limits it to tropical, subtropical and warm temperate gardens. Cold districts should look at a frost hardy flowering tree instead.

Why is it called the silk cotton tree?

The seed capsules split to release a mass of silky white floss around the seed. That floss blows about once the pods open, worth knowing before planting one near a pool.

How is an ex ground tree different from a potted one?

Open ground builds a stronger trunk and better natural form than a pot allows, and root pruning before lifting helps it re-establish. The trade off is weight: you need machinery and access on planting day.