I thought I would talk about “Bottle trees”.
The reason for that? I get so many darned questions about them from readers. I
get more questions from confused readers about this tree than any other landscape
tree. These aren’t usually good questions; they are problem questions. All
these problem questions makes you wonder if they should be planted in our warm
desert at all! They should but choose a good planting location and water them
carefully and not haphazardly.
What you are buying from the nursery (Brachychiton
populneum) is not really a “Bottle tree” at all. The correct name is “Kurrajong”.
The true bottle tree (B. ruprestis) is very different from the nursery
version because its trunk is truly shaped like a bottle! It’s a beautiful oddity
in the landscape. But the true Kurrajong hybridizes very easily with other
types of so-called “Bottle trees”. The growers propagate “Bottle trees” from
seed. Seed results from a cross between “mama” and “papa”. Unless the growers are
knowledgeable, who knows what you are getting?
The
number one questions I get is about watering. They grow primarily in the dry
interior of Australia. They are not a “swamp tree” and they are not a cactus
but something in between. When you water them, think of them more like watering
a palm tree (e.g., date palm) or even asparagus; they like to have their “toes”
constantly in water but without the soil around them continuously wet or they
will die.
Leaf drop can be normal. It frequently
will drop leaves just before or if it’s
not getting enough water (that does not mean water it more often!)
Plant in the spring, not during the hot
summer months. Unlike palm trees, they don’t grow well after planting during
the heat. Yes, they should be watered more often after first planting; maybe
twice a week in the spring or fall rather than once a week. But after one
growing season, apply a lot of water to a large area under its canopy
but water less often. This means either apply the water slowly as in drip
irrigation or build a mound or moat around the tree to hold the water so that
it sinks in the ground. Applying a lot of water at once uses the same amount
because “little sips are combined into one big gulp”.
The second problem I hear about from
readers is sunburn or sun scorch on their primarily horizontal limbs. Sunburn
on the limbs is for two reasons; the first is because this tree has very thin
bark easily sunburned by intense sunlight and the second reason is due to where
it’s planted. Never plant this tree in the hottest locations. It’s not a
mesquite, Cordia or sweet Acacia.