With its sumptuous vaporous feathers that bloom throughout the summer and its foliage of great finesse, the Albizia or silk tree brings an exotic touch to the garden. Easy to grow, it will delight all gardeners, even the less experienced. Here is everything you need to know about Acacia from Constantinople, another name of the Albizia.
Plant an Albizia or silk tree
L’Albizia loves sandy soils, well drained, and can even be satisfied with a limestone soil, or even a salty soil as is the case in maritime regions. On the other hand, he hardly appreciates the clayey 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. Better to install it away from the house or perimeter wall of the property because its roots tend to spread out.
In regions with harsh winters, it is better to plant the Acacia of Constantinople in spring, and where there is a beautiful winter mildness, it can be planted as soon asautumn which will promote 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 earth and rid it of stones, weed roots, various plant debris,
- Mix the soil 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 and then part of the soil / sand / manure mixture,
- Place the root ball in the center and spread the roots,
- Recap the hole,
- Pack the earth,
- Water copiously.
The Albizia can be used alone, in a group or in a row. It is not recommended to install it in the immediate vicinity of the swimming pool because when they are faded, its cottony flowers are easily dispersed by the wind and settle in the basin.
Maintain an Albizia or Acacia from Constantinople
The silk tree must be the object of regular care especially during the two years which follow its planting.
When he is still young he needsregular waterings, and more particularly in the event of drought. However, its roots should not bathe 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 to be watered if its leaves start to turn yellow.
During the spring, we 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 base of the shrub in order to preserve the freshness of the soil and to slow down the development of weeds. From October to November, it is necessary to hoe around the base, to weed and to remove the dead leaves. If you haven’t mulched now is the time to do it, making sure that the mulch layer is thick enough. This has the effect of protecting the young roots against possible frost.
In geographic areas where winters are rough, it is important to protect young birds against the cold by installing a wintering veil. In adulthood, silk trees tolerate between -4 and -5 ° C, or even down to -15 ° C if the weather is very dry but on condition that severe frosts are exceptional.
Parasites and diseases
Even though it is not very sensitive pests and diseases, this tree may still sometimes need special care.
Scale insects and psyllids
Albizia can be infested with mealybugs, but also by psyllids. These sucking insects are most prevalent in spring and summer and mainly attack the leaves and buds. Psyllids secrete honeydew just like mealybugs, and this sticky secretion stains the garden furniture installed under the tree.
But honeydew also causes the formation of a sooty mold due to a fungus on the stems and leaves. A spray of black soap to be renewed regularly is a natural solution.
Some silk trees can also be affected by Coral disease which causes pustules and an bark deformation. It is necessary to cut the affected branches and burn them, apply a healing mastic on the pruning 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 causes wilting and discoloration of the foliage. In the event of a problem of this type, all affected branches must be pruned and then burned.
Prune an Albizia
Pruning promotes flowering of the silk tree. It’s at the end of winter, end of February or beginning of March, anyway before vegetation resumes, that we can prune the Albizia. This is the best time of year to facilitate healing.
You can perform a short pruning if you opt for a crown formation size allowing to preserve the spreading natural port of this small tree. To do this, simply:
- To keep 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 pruning 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 be formed,
- the carpenter branches.
- Ask a tutor who can be kept for the first two years,
- Remove :
- rejections developing at the foot,
- the low side rods,
- damaged wood and / or dead wood.
- Cut back the stems with 5 eyes,
- Prune the tree by cutting only its arrow when it has reached the desired height and let the side branches develop at its end.
Stem pruning should only be done for the first time when the shrub reaches a height of at least 120-150 cm and should be repeated annually. Later, we are satisfied with a balanced size allowing to keep the harmonious silhouette of the Albizia only if it is 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 years, and preferably in summer because the rise of sap is less important at this time of the year. It is highly recommended not to cut the silk tree all at once as it does not appreciate drastic pruning which is traumatic at all.