Despite the fact that the globe trumpet tree (Catalpa bignonioides 'Nana') is one of the rather small trees, the crown can become quite sprawling as it ages. However, you can use simple means to keep the tree small and adapt it to local conditions.
How to keep a ball trumpet tree small?
To keep a globe trumpet tree small, you can prune every two to three years, limit the root space with a root barrier or, when grown in pots, prune the roots to control growth.
Can the size of the ball trumpet tree be limited?
It is possible to keep the ball trumpet treesmall by takingappropriate measures. If these are omitted, it can reach a height of up to 600 centimeters and reach a diameter of 600 to 800 centimeters.
When young, the growth of this cultivated form of the trumpet tree is characterized by a compact, spherical crown that only flattens with age and is shaped like an umbrella. That's why this tree is often planted in a place where it provides cooling shade for a seat.
What measures can be used to keep the tree small?
You can control the growth of the ball trumpet tree bypruning measures or limiting the root space.
The pretty trees tolerate pruning very well, even into old wood, and then sprout again willingly. To maintain the attractive shape, shorten the branches of the crown to around twenty centimeters every two to three years.
Why does a root barrier keep the globe trumpet tree small?
Since the tree hasless spacefor its roots,it grows slower and reaches a smaller size. Apply the root barrier directly when planting the ball trumpet tree:
- Dig a planting hole that becomes narrower towards the bottom. This reduces the growth of the roots.
- For sufficient stability, the diameter must not be less than 4 meters.
- Since the globe trumpet tree is a heartroot plant, the material should protrude five centimeters above the ground.
Can the ball trumpet tree be kept small in a pot?
With ball trumpet trees cultivated in pots, you can take advantage of the “bonsai effect” and keep the tree small bypruning the roots:
- Pot out the trumpet tree.
- Cut wedge-shaped pieces out of the root ball. This means that a large part of the fine roots necessary for the tree's survival are preserved.
- Replace the plant in the old, cleaned container.
- The gaps between the roots of the globe trumpet tree are closed with fresh substrate.
Tip
The ball trumpet tree is very robust
The globe trumpet tree is a very resilient tree that thrives wonderfully even on busy streets and in urban climates. Since it remains quite small by nature and the size can be easily controlled through appropriate measures, it fits extremely attractively into the urban garden, which is usually somewhat limited in terms of space.
