La Gleditsia triacanthos It is a tree of great ornamental value, which also grows fast and resists drought well. It can even be used as a shade plant, although it must be borne in mind that this is rather light when compared to that provided by other trees, such as Ceratonia siliqua for example.
Even so, it is a very beautiful plant, which it will give us many joys if we put it in the right place.
Origin and characteristics
Popularly known as the three-spined acacia, the three-spined acacia or the black acacia, it is a deciduous and spiny tree usually native to North America that It can reach a maximum height of 40 meters, although it is usual to stay between 10 and 12m. Its crown is wide, little branched, and formed by pinnate leaves with 10-15 pairs of leaflets, or bipinnate with 4-7 pairs of pinnae that measure between 0,8 and 2cm long.
The flowers are grouped in hanging clusters that sprout from the axils of the branches, and appear in spring. The fruit is a legume that can reach up to 25cm in length, and in whose interior we find 15 to 20 brown seeds of around 1cm in length.
Varieties and cultivars
There are two that are very interesting:
- Gleditsia triacanthos var. inermis: known as thornless black acacia. As its name suggests, it does not have thorns and, in addition, it does not produce fruit.
- Gleditsia triacanthus cv. sunburst: it is a conical cultivar, with green-yellow leaves that do not have fruits or thorns.
What care does Gleditsia triacanthos need?
If you want to have a copy, we recommend that you provide it with the following care:
Location
It is a tree that must be outside, in full sun. Its roots are invasive, so it is important to plant it at a distance of at least ten meters from pipes, walls, walls, etc. to avoid problems.
Earth
It will depend on where it is grown:
- Garden: accepts any type of soil, although it grows better in those that are fertile and have good drainage.
- Flower pot: use universal growing medium (for sale here).
Irrigation
As we anticipated, it is a species that resists drought well. But during the first year that it is in the ground, or if it is grown in a pot, it must be watered an average of 3 times a week during the summer, and an average of 1-2 times every seven days the rest of the year.
But beware, this has to be seen as an orientation: if the climate is hotter and drier, it will be necessary to water more often, and if on the contrary it is more humid, it will be necessary to water less. If in doubt, check the soil moisture before proceeding with watering, using a thin wooden stick or a digital moisture meter (for sale No products found.).
Subscriber
If you have in the soil the contribution of fertilizer is not very necessary, but if you have it planted in a pot it is advisable that you fertilize it in spring and summer for example with guano in liquid format (for sale here) following the indications specified on the product packaging.
Multiplication
Seeds
La Gleditsia triacanthos multiplies by seeds in spring, subjecting it to a pregerminative treatment called thermal shock, which consists of introducing them for 1 second in boiling water and 24 hours in water at room temperature.
After that time, they are planted in individual pots, putting a maximum of two in each one, and covering them with a thin layer of substrate. In this way, and once the seedbed has been placed outside, in full sun, they will germinate in about two weeks.
Cuttings
A somewhat faster way to get new copies is multiplying it by cuttings towards the end of winter. For this, branches of about 40cm long are cut, the base is impregnated with homemade rooting agents and are planted in pots with universal growing substrate mixed with perlite in equal parts.
Once placed outside, in semi-shade, and keeping the soil moist but not flooded, they will root in about a month.
Pruning
You don't need it. You should only remove dry, diseased, weak, or broken branches in the fall or late winter.
Planting or transplanting time
Whether you want to plant it in the garden or move to a larger pot, you have to do it late winter, when the minimum temperature remains above 10 degrees Celsius.
Rusticity
It is a tree that resists well the cold and frosts of up to -18ºC.
What uses does it have?
La Gleditsia triacanthos It is a plant of great ornamental value, ideal to have as isolated specimen or in alignments. In addition, it is even worked as bonsai.
Is it invasive?
This tree is considered as potentially invasive, and in many regions, such as in the Doñana Park (Spain), what is being done is to control it, since it grows faster than the plants that are autochthonous. Even so, it is a species that continues to be marketed in some nurseries.
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