Lilac Leaves Turning Brown

Lilac Leaves Turning Brown? (Here’s Why and How to Fix It!)

Lilac leaves turn brown and die due to Bacterial Blight disease. Lilac leaves turn brown and fall off due to leaf spot disease. Leaf spot disease can be caused by several fungal pathogens. Lilac leaves curl and turn brown due to leafminer damage. Brown edges are seen on Lilac leaves when the plant gets less water than required. Brown edges are also seen due to herbicidal damage.

Lilac plant gives out beautiful, light blue colored flowers. Lilacs are kept indoors for the beautiful blossoms that give out a pleasant scent.

Lilac plant blooms in the spring. Lilac plants can be grown into loose hedges around the property. I did this in the garden.

Lilacs don’t require much maintenance. You only need to prune them once a year. Is your Lilac turning brown?

These plants are usually hardy, so why does this happen. In this article, we shall explore the reasons why Lilacs turn brown. We’ll discuss the solutions.

Lilac leaves turning brown and dying

Lilac leaves turn brown and die when the plant is suffering from Bacterial Blight. Bacterial Blight infects all kinds of Lilacs.

Bacterial Blight infection is first seen in the spring. The disease spreads rapidly in the monsoon season. White flowering varieties are commonly affected by this disease.

The disease-causing bacteria reside in plant debris and soil. They enter the plant through natural openings or wounds.

What does Blight look like on a lilac bush?

Bacterial Blight first appears as olive-green spots that develop into water-soaked areas. You’ll start seeing small, brown spots on the foliage.

The branches die back and the foliage becomes distorted. The brown spots on the leaves have a yellow margin.

Leaf curling and twisting are seen on younger leaves. Brown spots appear on the stems and leaves in the spring. The flowers wilt and turn brown. The unopened flower buds turn black.

Know that the disease has progressed when the brown leaves have turned black.

Lilac Bacterial Blight treatment

Lilacs are usually hardy but they’re prone to fungal diseases like many other plants. Follow the instructions below to treat a Lilac plant suffering from Bacterial Blight.

  • Give your plant an aggressive pruning if you see any initial signs. Cut back all the diseased parts of the Lilac to prevent the disease from spreading.
  • Prune at least 12-inches below the site of blight infection. Dip the pruners in a 10% bleach solution between each cut.
  • Space the plants properly to provide proper ventilation. Get rid of the leaf debris in the garden regularly.
  • You can plant Bacterial Blight resistant varieties in your garden.

Resistant Lilac varieties

Selecting varieties that have good tolerance or resistance to Bacterial Blight reduces a lot of headaches for the gardeners.

Japanese Tree lilacs (Syringa reticulata) are resistant to many diseases. Consult the closest Horticulture University to know the varieties that are resistant in your zone.

Lilac leaves turning brown and falling off

Lilac leaves turn brown and fall off when the plant is suffering from Leaf spot disease. Leaf spot is a fungal disease caused by several pathogens.

This disease is a by-product of high humidity around the Lilac plant. The disease might or might not cause defoliation.

Initially, the leaves turn yellow which then turn brown and die back. The leaf spots start small and are restricted by the veins.

Prevent Leaf spot disease in Lilac

  • Trim the affected shrub and get rid of all the debris to prevent future infections.
  • Prune all the dead branches as a precaution.
  • Spray fungicide on your Lilac in the spring as a preventative measure. Repeat once every fortnight through the monsoon season for effective prevention.

Lilac bush leaves curling turning brown

Lilac bush leaves curl and turn brown due to leafminer damage. The lilac leafminer is the larval form of a small brown moth that feeds on Lilac and Privet.

The larvae overwinter in the leaf debris. The pupae overwinter in the curled-up leaves. The larvae start feeding on the leaf tissue and cause blotches.

They soon emerge and curl up the leaves around them with the help of silk. They skeletonized the curled-up leaves.

Several generations are seen every year, which is why control is crucial. The infestations become severe in the midsummer and fall seasons.

How to control leafminers on Lilac

  • Cut the mined, curled-up leaves and dispose of them properly. This deters the pest from overwintering in the debris.
  • Control the small populations in spring to prevent heavier infestations later on.
  • If the infestation is severe, apply an insecticide labeled for this pest.

Note: Lilac leaves curl and turn brown when the plant is affected by Powdery Mildew.

Lilac bush leaves turning brown on edges

Lilac bush leaves turn brown on the edges due to a lack of water. This can also happen due to herbicidal damage(2,4-D).

The leaves turn brown on the edges and curl upward when the plant is underwatered. Track the watering sessions to better understand your Lilac’s needs.

Water your lilacs once every fortnight for the best results. Young lilacs need to be watered once weekly. Make sure the ground is moist up to a depth of 12 inches.

Overwatering leads to problems too, so water your Lilac consciously. Check the soil with fingers if needed.

Lilac leaves also turn brown on the edges when there’s herbicidal damage. Make sure there’s no wind when applying herbicide.

There’s no treatment for herbicidal damage, you just let the plant revive. Don’t apply herbicide on a rainy day.


If you’ve read the article properly, you’ll know that the reason behind all these diseases is improper cultural practices.

Ensure that there’s no leaf debris around your Lilac plants. Don’t let the Lilac leaves get wet, moisture invites disease-causing pathogens.

Prune your Lilac bush properly and make sure there’s sufficient ventilation between the plants. Space the plants generously.

Act as soon as you see brown spots/streaks on the foliage. Diagnose the problem properly and try to control it at an early stage.

Happy Gardening 🙂