Indian lilac: planting maintenance pruning and flowering

With its trunk which more or less evokes that of the plane tree, the Indian lilac or Lagerstrœmia is a deciduous shrub with leaves similar to those of the privet. It is of the most beautiful effect with its spectacular flowering from June to October and is well suited to small gardens due to its low development since it does not exceed 4 to 5 meters in height when adult. Let’s see how to plant an Indian Lilac, also called summer lilacand what their needs are.

Planting an Indian Lilac or Summer Lilac

Lagerstroemia can be grown both in the ground and in pots. This second solution is highly preferable in regions with a harsh climate because it allows it to overwinter.

Planting in the ground

Ideally, we plant the Indian Lilac in autumn, when it has lost its leaves, especially in regions with mild winters. But we are waiting for spring, between March and May, if severe frosts are feared in climates where they strike relatively early. It is also absolutely necessary to avoid planting it when it is too hot and very dry.

Before planting, it is necessary to prepare the soil by digging to a depth of 60 cm and adding to the garden soil from mature compost or manure and heather soil if necessary. We must remove stones, weeds and loosen the soil well. Then proceed as follows.

  • Soak the root ball in its container by immersing it in a basin of water to rehydrate the roots and facilitate stripping.
  • Dig a hole twice as wide as the root ball.
  • Place enriched soil at the bottom of the hole.
  • Take the shrub out of the container and untangle the roots without damaging them.
  • Install a stake according to the variety chosen.
  • Place the Summer Lilac in the center of the hole so that the surface of the root ball is flush with ground level.
  • Fill in with the rest of the soil.
  • Tamp down and water copiously.
  • Attach the shrub to the stake without overtightening the ties.

It is recommended to install a mulch all around the foot from the planting.

Container planting

So that Indian Lilac can be overwintered if the climate is harsh, it is best to plant it in a pot. We choose a large bin, 50 to 60 cm deep and in diameter, bottom pierced imperatively to promote drainage. Must also :

  • Place a draining layer such as gravel, pozzolan or expanded clay balls at the bottom of the tank,
  • Fill the pot with a mixture consisting of equal parts of 40% planting soil, 40% good garden soil or topsoil and 20% organic manure.

As soon as the Lagerstroemia is planted in its container, it should be watered generously and placed in the sun, sheltered from the wind.

Growing an Indian Lilac (Lagerstroemia indica)

Indian lilac needs soil not calcareous, well draining, cool in summer et humus. It tolerates clay soils. The original species likes hot climates, so it is essential to install it in a sunny position, sheltered from the winds, conditions sine qua non so that it can bloom.

In dry and very hot climates, it can acclimatize to partial shade even if it is a full sun shrub. It should be noted that today there are many varieties of Indian lilac that are more resistant to frost since some can withstand temperatures down to -17°C, such as Indiyia Charms, a fairly recent variety. This makes it possible to cultivate this shrub in almost all our French regions, caution being however required in coastal areas because the spray does not suit him. When buying a Summer Lilac, it is therefore essential to ensure that the local conditions are suitable for it.

Caring for an Indian Lilac

In exchange for some good care, this undemanding shrub will bloom profusely.


It must be watered very regularly after planting so that its deep rooting is encouraged. After a few years, the shrub can withstand drought. When it is prolonged, it must still be watered copiously from time to time so that it can flower generously.


It is strongly recommended to install a mulch of crushed cocoa pods, flax flakes or even hemp at the foot to maintain a cool ground. This also limits the development of weeds and protects the roots against frost. Let’s not forget that from -6°C, certain varieties must be protected with a winter sail. This must be opened in the event of softening and removed when severe frosts are no longer to be feared.


An amendment to homemade organic manure must be incorporated into the soil when spring arrives by superficial scratching. This boosts the – relatively slow – growth of the Summer Lilac and promotes its summer flowering. In order to prolong flowering, it is useful to add two additional fertilizers for flowering shrubs and/or roses, one in June and the other stream august.


It is not absolutely essential to prune a Lagerstroemia. However, if you want it to keep a nice silhouette or if the shrub is grown in a small garden, on the terrace or balcony, pruning is very useful, not to mention that it improves flowering. We can therefore prune the Indian Lilac in March. A very short size is not likely to disturb it since it flowers on the shoots of the year, but it is essential for each branch to keep between 2 and 3 eyes. We take the opportunity to remove a few branches at tree heart so that the heat penetrates more easily.

Pests and diseases

Although not very sensitive to parasites, Indian lilac can be the target of scale insects and whiteflies during its wintering period in greenhouses, as well as red spider mites.

As for the disease to watch out for, it ispowdery mildew which can especially appear on old varieties, the most recent showing better resistance to this powdery mildew or white rot. Do not hesitate to spray sodium bicarbonate or use a sulfur product against powdery mildew, respecting the dosages clearly indicated on the packaging.

Indian lilac flowering

The summer lilac flowers come in many colors (white, red, purple, pink or mauve) and are grouped in panicles. Its inflorescences do not go unnoticed. They literally light up the garden provided that the shrub has been able to benefit from a lot of heat, sufficient watering to keep the soil cool and fertilization. But the reduction of its secondary branches by about 60% in March can really promote its flowering.

That he wishes a shrub nainat drooping habit or at upright habit, the gardener can find the Indian Lilac that suits him best depending on whether he wishes to use it in alignment, in a group, isolated, or – as we have seen previously – in a container. This beautiful lilac can be combined with other summer or late blooming shrubs. Finally, it should be noted that the flowers of the Lilac of the Indies make it possible to create delightful bouquets and hold very well in a vase.

Leave a Comment