Visually, the trumpet tree (Catalpa bignonioides) is an extremely impressive sight, especially when the exotic tree is already a few years old. The strong green, heart-shaped leaves are up to 20 centimeters long and form a lush foliage, which, however, only appears quite late in the year. The orchid-like, white flowers develop into a magnificent sea of flowers between June and July, from which legumes up to 40 centimeters long develop by autumn. These contain seeds that can also be used to propagate the trumpet tree.
Growing a trumpet tree from seed is very promising
Harvest seeds in spring
In contrast to most native woody plants, however, the seeds of the trumpet tree do not ripen in autumn, but only in the following spring. You can tell when the time is right by the color of the pods - as long as they are still green, they can remain on the tree. You can start harvesting as soon as the fruit turns brown. This is usually the case between around January and March. The very fine seeds it contains are flat and have tufts of hair. However, trumpet trees do not develop seeds every summer, and sometimes the pods remain empty. You have the best chance after a very warm and long summer.
Stratification is necessary
Trumpet tree seeds are provided with a germination inhibition, which must be broken by a cold stimulus. It therefore makes sense to either leave the pods on the tree over the winter or to stratify the seeds. This is done by placing the seeds, wrapped in a tightly sealed container with moist sand, in the crisper of your refrigerator for a few weeks. In many cases, purchased seeds are already stratified, so this step can be omitted.
Sow trumpet tree seeds
Further cultivation works very easily according to the following scheme:
- First let the seeds soak in lukewarm water (change it several times!) for 24 hours.
- Sow them in a planter with potting soil and cover them lightly with substrate.
- Keep the substrate slightly moist evenly.
- Place the potty in a propagator or cover with foil.
- The planter is best kept in a bright and warm place.
- Ventilate several times a day.
The very germinable seeds often show the first tender green after just a few days.
tips
If trumpet trees feel comfortable in their location, they tend to self-propagate through seeds or planters.