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Why Are My Lilac Bushes Turning Brown? (How To Revive It)

Lilac bushes frequently flower beautifully in the summer, generating robust growth for quite a while, and then, for unknown reasons, begin to turn brown and look uncomfortable by September. Why are my lilac bushes turning brown? You may wonder.

Your bush could be infected with lilac blight, a bacterial plant disease! It’s not always completely obvious why this occurs, but it’s common among lilac growers. Do your lilac’s new blooms and twigs appear blackish, as if charred by a blowtorch?

Lilac blight thrives in the spring, particularly if rains follow a slow winter or winter harm. Plant forensic scientists are alerting that this year could be a good year for the illness.

Let’s look a little deeper to see why this tends to happen and what you could do about it!

Why Are My Lilac Bushes Turning Brown?

Initially, the leaves appear to be perfectly healthy, but they appear to have been exposed to an open flame after a short period. The dark black splotches on one side of leaves and shoots indicate disease activity. Flowers will droop and turn brown, and sealed flower buds will turn black.

Lilac blight is harder to monitor because it is best to buy blight-resistant cultivars whenever you replant lilacs. It’s also a good idea to spread and trim your lilac plants so they don’t rub against each other so air can come and go around them.

Do not over-fertilize young species because too much nitrogen promotes disease severity. Older stems will innately turn brown if your foliage is developed. Since the aged branches of your lilac bush are dropping dead back, components of it may be turning brown.

Some mature sections will die and need to be trimmed until all dead matter is eliminated.

If your lilac is very old, you might have to cull the sections all the way down to the soil; this will remove the browning, promote new progress, and revitalize your plant over time.

Bacterial blight, also renowned as Shoot or Blossom Blight, is caused by inappropriate fertilization, wildlife harm, or prolonged drought; this can affect a variety of lilac cultivars, with some research indicating that white lilacs are particularly vulnerable.

Brown marks on leaves and roots are caused by bacterial blight. The patches can cause the foliage to twist by enlarging and deforming them.

The signs may spread to the stems as the disease progresses, transforming them into black and wilting. Wilting is a clear indicator that the plant’s health is deteriorating and maybe getting killed.

How To Stop Lilac Bushes From Turning Brown

When your lilac is displaying symptoms of bacterial blight, the best approach is to prune it aggressively.

You’ll need to drastically cut all of the disease-ridden segments of the plant to save all the rest of it. The whole lilac could shrivel and die if you don’t do this.

It may appear to be a bummer to cut your lilac back so vigorously, but it is the only way to correct the situation. To save the plant, you’ll need to be very comprehensive with your trimming.

Diagnosis And Control

Eliminate afflicted foliage with clean, purified shears and cull the branches back about 10 to 12 inches underneath the observable infestation.

Blight can be extremely infectious and difficult to eradicate.

Disinfect or discard pots, gloves, equipment, or anything else that has interacted with this ailment, or it will spread like wildfire.

To help keep bacterial blight at bay, use a copper fungicide with a mancozeb-containing fungicide.

Utilize them 2 or 3 times in 1 to 2 weeks, as leaf growth begins before the bacterial blight takes hold.

Water Appropriately

Young lilacs (just under a year old) are chronically dehydrated before their roots have an opportunity to establish themselves and may gradually turn brown if submerged, predisposing them to infection.

Amongst the most critical parts of lilac care is their moisture requirement.

During the hot summer months, they’ll require a little extra water.

Check on your plant regularly and water it when the top bit of soil feels dry to the touch.

Once the roots of a young plant have formed themselves and the weather is not too warm, your lilac bush may only require irrigation once or twice a month.

Frequently Asked Questions

What is the best way to save a dying lilac bush?

On older plants that aren’t flowering, apply a fertilizer with a nitrogen-phosphorous-potassium proportion of 5-10-5. Fertilizers with a pH of 0-15-0 or 0-45-0 can also be used. Nourish once in the spring and once in the fall by excavating a couple of  holes in the soil close to each lilac plant and filling each hole with 1 cup of fertilizer.

Why are my lilac bush’s fronds twisting and beginning to turn brown?

A mixture of factors can trigger curling lilac leaves, but the leaf miner insect and certain disorders are two of the most prevalent. It could also indicate that your lilac bush isn’t receiving sufficient moisture or sunlight.

When Should You Trim?

The right opportunity to trim back lilacs is starting from the late summer, a few weeks after the blossoms have dimmed.

When you notice swarming, prune a few branches to allow more air to circulate.

Intensifying airflow will help your lilacs stay healthy and prevent them from turning brown.

Aged lilacs require more frequent pruning closer to the soil.

The succeeding year’s growth will be healthier as a result.

Just make sure not to eliminate the flowering buds for the following year.

Is Bacterial Blight Preventable?

Yes, bacterial blight can be avoided if the proper precautions are taken, which primarily entail planting an impervious lilac. Finding disease-resistant lilacs that you can plant will give you more confidence that they will be okay.

If you can find disease-resistant lilacs to plant, you won’t have to tackle these issues in the future. Those who are more concerned with preserving their existing lilacs will have to follow the repair instructions.

You can change things around, but it will require some dedication and hard work to eliminate bacterial blight.


Lilacs are a breathtaking scenery plant with different hues and a fantastic fragrance, but when your lilac bush starts to turn brown and look miserable, it can be heartbreaking.

We’re confident that if you read through all of the care helpful hints in this guide, you’ll quickly figure out why your lilac bush is starting to turn brown and be ready to place a plan to nurse it back to health.

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