Grow and Care for Australian Bottle Tree

Grow Australian bottle tree in full sun on soil that drains, and water it only until it is established. Australian bottle tree is Brachychiton, also sold as Queensland bottle tree.

Give it full sun, soil that drains, and water only until it is established

Australian bottle tree is a landscape tree with a swollen, bottle-shaped trunk and narrow adult leaves. Give it a full day of sun and soil that drains. Water a newly planted tree deeply through the first year so roots go down. After that, water only in a long dry spell. The trunk stores water, so an established tree rides drought better than a wet hole. [1] Overwatering is the usual reason roots rot. A dry or cooler spell can drop some leaves; that is normal rest, not a reason to soak the bed. A hard freeze can take young wood. Site it in the warmest corner you have, or grow a small tree in a pot you can roll inside.

Plant a nursery tree, and leave room for a 20-to-40-foot canopy

Buy a nursery tree whose flare you can see at the top of the mix. Set that flare even with, or slightly above, the surrounding soil, in full sun, 20 to 30 feet from buildings and other trees so the canopy can fill. The bottle shape usually starts to show around year five to eight; do not expect a fat trunk on a one-year seedling. [2]

1. Choose a healthy nursery tree with a visible flare, not a root-bound tree jammed into a small pot.
2. Dig a hole as deep as the root ball and about twice as wide. Backfill with the soil you dug out. Do not put fertilizer in the bottom of the hole.
3. Set the mix line even with, or slightly above, the surrounding soil. Water it in.
4. Leave 20 to 30 feet from buildings, power lines, and other trees. Keep mulch a few inches off the trunk so the bark stays dry.

Keep a young tree in a pot that drains

Where winter regularly freezes, a pot is how a young tree stays alive. Use a pot with a hole in the bottom, a mix that drains, and a tree you can wheel inside before a hard freeze. This is not a houseplant for a 40-foot canopy; once the tree is too heavy to move, it belongs in the ground only where hard freezes stay rare.

1. Start in a pot that drains. A lightweight pot, or a platform with wheels, makes the winter move easier.
2. Fill it with a gritty mix that drains. Water when the top of the mix is dry, and empty standing water from the saucer.
3. Set the pot in full sun outdoors for the warm months. Move it inside before nights stay cold enough to bite the leaves, and keep it by the brightest window you have.
4. Expect some leaf drop after a move or a dry spell. The tree usually leafs out again once it is warm and bright.

How to grow an Australian bottle tree from seed

Fresh seed sprouts readily in a warm pot that drains. The boat-shaped follicle is lined with hairs that irritate skin, so wear gloves when you open a pod. A seedling is not a named street tree, and the bottle shape still takes years. [3]

1. Wear gloves. Split a dry follicle, tap the seed out, and keep the hairs off your skin and clothes.
2. Sow the seed about a quarter inch deep in a warm pot that drains. Barely cover it.
3. Keep the mix just moist, not soggy, in a bright, warm spot. Do not soak a seedling the way you would a tropical houseplant.
4. Treat whatever comes up as a seedling. The bottle trunk usually starts to show around year five to eight. Buy a nursery tree if you want that silhouette sooner.

Raise the lower limbs so the bottle trunk can show

Prune this tree lightly. In late winter, take out dead or crossing wood, then raise a few of the lowest limbs each year so the swollen trunk can show as the canopy lifts. Do not top the tree to shorten it. A hard cut on a young leader delays the bottle shape you planted it for.

1. Wait until late winter, after the coldest nights, before you cut live wood.
2. Remove dead, damaged, or rubbing branches back to the collar.
3. Raise a few lower limbs each year if you want a clean trunk. Leave enough canopy so the tree still makes food.

Not a bottlebrush — and not a flame tree

Bottlebrush is Callistemon, a shrub or small tree with bottle-brush flower spikes, not a swollen trunk. See How to Grow Bottlebrush if the plant in front of you is a red or cream spike and the stem is ordinary wood.

Flame tree in a U.S. search is usually royal poinciana (Delonix), with wide ferny leaves and a sheet of red summer bloom, or Chinese flame tree, which is Koelreuteria. See How to Grow Golden Rain Tree if the fruit is a papery lantern. Coral tree is Erythrina; see How to Grow Coral Tree if the flowers sit on thorny wood. Illawarra flame tree is another Brachychiton with a red flower show and no bottle trunk. If the tag says Illawarra flame, you bought the flower tree, not this bottle trunk. [4]

Ponytail palm is Beaucarnea, a swollen base with a tuft of strap leaves, sold as a houseplant. See How to Grow Ponytail Palm if the plant is a pot specimen with a caudex, not a 20-to-40-foot landscape tree. A baobab has a similar fat trunk in another genus; do not buy it as a substitute for this Australian tree.

Water a new tree until it is established, then ease off so the bottle trunk stores water without sitting in a wet hole.