With its sumptuous vaporous feather dusters that bloom throughout the summer and its extremely fine foliage, the Albizia or silk tree brings an exotic touch to the garden. Easy to grow, it is a delight for all gardeners, even the less experienced. Here is everything you need to know about Acacia of Constantinopleanother name for the Albizia.
Plant an Albizia or silk tree
The Albizia loves sandy soils, well drained, and can even be satisfied with limestone soil, or even salty soil, as is the case in maritime regions. On the other hand, it does not like clay soil which tends to retain water. We reserve a very sunny exposure and warm, so sheltered from the winds because if most of the varieties can withstand negative temperatures in adulthood, it is not very hardy during its first years.
This tree can, in adulthood, reach a height of a good ten meters It is better to install it away from the house or boundary wall of the property because its roots tend to spread out.
In areas with harsh winters, it is best to plant the Acacia Constantinople in springand where there is a nice winter mildness, it can be planted as soon asfall which will favor on the one hand its rooting, on the other hand its recovery.
The method of planting an Albizia is as follows:
- Dig a hole 2.5 times larger than the root ball,
- Immerse the root ball in a bucket of water to rehydrate it,
- Loosen the soil and rid it of stones, weed roots, various plant debris,
- Mix the earth with sand and planting compost or even with manure or other organic amendment,
- Uncross the roots by scratching them without damaging them,
- Place gravel at the bottom of the planting hole to create a draining layer then part of the soil/sand/manure mixture,
- Arrange the root ball in the center and spread the roots,
- Plug the hole,
- Tamp the earth,
- Water copiously.
The Albizia can be used alone, in a group or in alignment. It is not recommended to install it in the immediate vicinity of the swimming pool because when they are wilted, its cottony flowers are easily dispersed by the wind and are deposited in the basin.
Entertain an Albizia ou Acacia of Constantinople
The silk tree must be regularly cared for, especially during the two years following its planting.
When he is still young, he needsregular watering, and more particularly in case of drought. However, its roots should not be immersed in water. Watering should be continued until the end of September for the first two years. Then, when it has reached maturity, it only needs watering if its leaves start to turn yellow.
During the spring, you can bury a little fertilizer granules for flowering shrubs at the foot of the subject in order to improve its flowering.
We recommend installing a mulch at the foot of the shrub to keep the soil cool and slow down the development of weeds. From October to November, it is necessary to hoe around the base, weed and remove dead leaves. If you haven’t mulched, now is the time to do so, making sure that the layer of mulch is thick enough. This has the effect of protecting the young roots against possible frosts.
In geographic areas where winters are rough, it is important to protect young subjects against the cold by installing a winter veil. In adulthood, silk trees withstand between -4 and -5°C, even down to -15°C if the weather is very dry, provided that severe frosts are exceptional.
Pests and diseases
Even though he is not very sensitive pests and diseases, this tree may still sometimes need special care.
Mealybugs and psyllids
Albizia can be infested with scale insectsbut also by psyllids. These sucking insects are most prevalent in spring and summer and mainly attack leaves and buds. The psyllids secrete honeydew just like scale insects, and this sticky secretion stains the garden furniture installed under the tree.
But honeydew also leads to the formation of a fumagine due to a fungus on the stems and leaves. A spray of black soap to renew regularly represents a natural solution.
Some silk trees can also be affected by Coral disease which leads to pustules and an deformation of the bark. Cut the affected branches and burn them, apply a healing mastic to the prunings then spray Bordeaux mixture (natural antifungal) on the tree.
Fusarium wilt is a fungal disease against which there is no treatment. It is favored by humidity and heat and leads to wilting and discoloration of foliage. In the event of a problem of this type, it is necessary to prune all the affected branches and then burn them.
Prune an Albizia
Pruning favors flowering of the silk tree. It’s at the end of winter, at the end of February or the beginning of March, in any case before the resumption of vegetation, that the Albizia can be pruned. This is the best time of year to facilitate healing.
One can carry out a succinct pruning if one opts for a crown formation pruning allowing the natural spreading habit of this small tree to be preserved. To do this, simply:
- To preserve the branches of a beautiful vigor which form the natural crown of the tree,
- To remove dead wood,
- To remove the branches which leave in all directions and cross or are badly placed.
The silk tree can also benefit from a size on rod which consists in :
- Preserve only:
- the most vigorous and straightest stem so that it becomes the trunk of the Albizia and that over time a crown in umbrella shape can form,
- the carpenter branches.
- Lay a stake that can be kept for the first two years,
- To delete :
- suckers developing at the foot,
- the low side rods,
- damaged wood and/or dead wood.
- Cut back the stems at 5 eyes,
- Top the tree by cutting only its arrow when it has reached the desired height and allow the side branches to develop at its end.
Stem pruning should only be done for the first time when the shrub reaches a height of at least 120 to 150 cm and it should be repeated every year. Later, one is satisfied with a size of balance making it possible to preserve the harmonious silhouette of Albizia only if that proves to be essential.
Finally, a reduction size can be undertaken if the tree is deemed to have grown too large. But it must be done over three consecutive yearsand preferably in summer because the rise of sap is less important at this time of the year. It is highly recommended not to cut down the silk tree all at once as it does not like drastic pruning at all which is traumatic.