Castanospermum australe - the Moreton Bay Chestnut or Blackbean - is the only species in the genus Castanospermum in the family Fabaceae, native to the east coast of Australia, and increasingly popular as a houseplant.
It is a large evergreen tree growing to 130 ft (40 m) tall in its natural habitat - but of course considerably less in our homes! - with broad, pinnate 5.9 in (15 cm) long leaves with 11-15 leaflets, and bicoloured red and yellow pea-like flowers.
Sowing & planting
100 - 300
6 - 7
Plant my moreton bay chestnut
Castanospermum prefer warm and dry environments it does particularly well in the comfort of our houses and apartments. It needs light, but not direct sunlight, and it hates drafts and temperature changes. It doesn't handle being moved around well!
Avoid planters with water reservoirs — castanospermum roots can't handle constant submersion.
Water my moreton bay chestnut
As soon as the soil is dry to a depth of one or two centimeters, water your yucca, ensuring you moisten all of the topsoil.
During growth seasons (spring, summer), watering should be regular, about once a week, but controlled, to make sure the roots don't drown. In autumn, gradually reduce watering until winter, when once-monthly watering will suffice.
Spray my moreton bay chestnut
In dry weather, spray your castanospermum with soft water, clean the dust on the leaves: it will be all the more beautiful and you will protect it from red spiders - its main enemy!
Fertilize my moreton bay chestnut
In summer, add liquid fertilizer for green plants every 2 weeks. You can also add slow release fertilizer pellets to the soil mix when planting or repotting. Stop all fertilizer treatments at the end of summer.
Repot my moreton bay chestnut
Every three or four years, at the end of winter, repot your castanospermum!
You can also repot your castanospermum when you purchase it, especially if the pot falls or tips too easily. That's a sign your castanospermum cramped for room!
Choose a large clay pot, approximately 5cm larger than the original, with heavy, thick walls to help your plant balance. castanospermum has a very high centre of gravity and tends to lean and tip over.
Thoroughly spray down the original pot and place any leftover stones, clay pellets and drainage rocks in the bottom of the new pot. Mix potting soil for green plants with a little jardin soil, and fill a a third of the pot.
Remove the castanospermum from its pot. If the pot is stuck, you can cut it with shears or pruners.
Clean off the roots, place the root ball on the potting soil mixture and cover with more potting soil.
Tamp the soil firmly, and finish by watering!
The next water can be down in one week. Let your castanospermum dry a little so it can lay down it's roots.
Propagate my moreton bay chestnut
There isn't really a specific season to take a cutting from you castanospermum!
Using sharp pruners, cut a section of healthy branch at a 45 degree angle, then remove the oldest leaves and keep only the four or five newest leaves at the tip. Finally, soak the cutting in a glass of water and leave it in a warm room.
Change the water regularly. It will only take a few weeks before you see roots appearing at the cut end of the stem.
When you're confident that there are enough healthy new roots, you may plant the cutting in a light substrate.
Check on my moreton bay chestnut
Castanospermum are very sensitive to scale insects, which are small brown bugs often found in large numbers on leaves. You may also notice a white felt forming on the back of the leaves. To get rid of scale insects, simply clean them off the leaves by wiping a q-tip over top — the bugs will cling to the q-tip.
Put outside my moreton bay chestnut
If you can, place your castanospermum outside, in half-shade.
Shelter my moreton bay chestnut
Bring your castanospermum indoors in a room at a temperature of 18-22 ° C, not going down below 15 ° C for the whole winter. Place it near a window, in bright light, without direct sun, sheltered from cold drafts.