Lilacs put on a wonderful display unless their leaves start turning brown. And this is a warning that your lilacs need attention. But why are they turning brown?
There are 5 causes why your lilacs are turning brown. They are Diseases, Pests, Improper Watering, Imbalanced fertilizer, and Weather Damage.
In this article, I am going to discuss why the browning is happening and how to solve this. So, keep reading to treat your lilacs and turn the leaves back to luscious green.
Without making any delay, let’s fire away-
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5 Reasons For Lilac Leaves Turning Brown
1. Bacterial And Fungal Diseases
One of the major reasons for lilac bush’s leaves turning brown and falling off is bacterial blight. It is also known as shoot blight. Blight makes brown spots on the leaves and stems.
The spots later get bigger. Later the whole leaf turns brown and starts curling. When severely infected by blight the lilac flowers also turn brown. White lilacs are most vulnerable to blight. It can be hard to get rid of.
Verticillium Wilt is also a fatal disease of lilac that turns the leaves brown. But it is not that common to happen. This disease also weakens the plant very much. In most cases, the lilacs don’t survive.
Your lilacs need the best copper fungicide to get rid of the blight and other leaf fungi (Our Pick: Bonide Copper Fungicide). Apply it every 2-3 weeks interval.
Remove the infected leaves and heavily infested branches with a sharp pruning shear. If you do not remove the infected parts they will spread to the whole plant. As a result, the plant will wilt and die.
Dip the pruning shears in a 10% bleach solution before and after pruning. Burn the debris or throw them carefully in the garbage. Do not let the infected parts get in contact with other plants.
Some homemade recipes are given here:
Recipe 1:- Baking Soda Recipe
- 3 teaspoons of baking soda
- 1 teaspoon of liquid dishwashing soap
- 1 gallon of water
- Mix these ingredients and put them into the sprayer
- Spray on both sides of your lilac leaves.
- Do not store the leftover mixture.
- Always use a freshly prepared one.
#Recipe 2:- Cinnamon Spray Recipe
- 2 tablespoons of cinnamon powder
- 1 liter of water
- Mix them together
- Let this solution rest overnight
- Then strain with a fine cloth and pour it into the sprayer.
- Spray on both sides of the lilac leaves.
Note: Use all the homemade solutions in a small leaf before spraying into the whole plant. All of these may not be suitable to your lilacs.
Plant disease-resistant varieties of lilac. Plant them in a sunny place. Keep proper spacing at least 4-6 feet apart. Prune the lilacs when it’s dry season and no rain is forecast for the next few days. Before transplanting your lilac, always wash the roots very well so that any soil-borne fungi get washed off.
2. Lilac Pests
Lilacs are often attacked by beetles, borers, and scales. These insects feed on the lilac leaves. As a result of their feeding, the leaves start turning brown and curling up. Borer insects even make holes in the leaves.
These bugs create bigger problems by attacking in a large number. They can injure the lilac plant very much. And this will surely affect the blooming.
You need to treat these insect problems with the best pesticide that is not chemically harmful to other plants and living beings (our pick: Monterey organic Garden Insect Spray). Also, keep in mind that improper insecticide will damage healthy plants and burn the leaves. In this case, the outcome will be the same, that is brown leaves.
Pruning will help to stop the spread. Prune away the heavily infested branches. Horticultural oil, neem oil are very effective against pests.
The recipes are given below:
#Recipe 1:- Horticultural Oil Recipe
- 2 teaspoons of liquid dish soap
- 1 cup of any oil like soybean oil or olive oil or vegetable oil.
- Mix these ingredients very well and store the mixture in a bottle.
- Add a tablespoon of this mixture with every 500 ml of water and pour it into the sprayer.
- Spray thoroughly on your lilacs
#Recipe 2:- Neem Oil Recipe
- 1 tablespoon of neem oil
- 2 liters of water
- Add these ingredients together and spray on the lilac plants every week
- Use this as a regular preventive measure against pests.
#Recipe 3:- Three-In-One Insect Spray Recipe
- One small bulb of garlic
- one small onion
- 3 teaspoons of liquid dish soap
- Make a paste of garlic and onion in an electric blender.
- Strain the mixture with a fine cheesecloth
- Now add the liquid dish soap and mix very well
- Add water to make it a 2-liter solution.
- Spray it on both sides of the lilac leaves.
3. Water And Soil Problem
Lilacs leaves turn brown on the edges and curl if they are underwatered. The lilacs need plenty of water to get established. During hot summers the young lilacs need an extra bit of water.
Lilacs grow best in neutral soil. If the soil pH isn’t between 6-7 the lilac leaves sometimes can turn brown and curl.
Check your soil with a moisture meter and water them as much as they need (Our pick: Atree Soil Soil Tester Kits with Moisture, Light, and PH Test for Garden). You can also feel the top layer of the soil by pressing your hand against it to see if it’s dry.
But once the lilacs have been established they will need watering only twice a month. Though they’ll need a little extra water during the hot summer months.
Roots take some time to absorb water. So, if the soil is very dry then water the roots slowly. Make sure the soil holds enough moisture but drains enough amount of water also.
For acidity, you can add lime, and for alkalinity add sawdust or peat moss. Avoid overhead watering and do not wet the leaves. This will help to prevent other fungal problems.
4. Lilacs Lacking Fertilizer
If your lilacs are not getting a balanced fertilizer, especially potassium and phosphorus, they can turn brown on the edges. Phosphorus is also required to produce good-quality blooms. But don’t over-fertilize them. Because of too much nutrients in the soil damages the roots of the lilac.
If you spray fertilizer in hot weather then the same browning of the leaves will happen.
Try this homemade fertilizer on your lilacs:
#Recipe 1:- Homemade Potassium Fertilizer Recipe
- 4 banana peels (dried)
- 4 eggshells
- 4 tablespoons of Epsom salt
- 5 tablespoons of water
- Put the banana peels and eggshells into a grinder and mix them into a powder.
- Add the Epsom Salt and water to it.
- Shake and mix very well
- Mix this solution with some irrigation water.
- And water at the base of your lilacs
5. Weather Damage
Both cold winter and dry summer can bring brown leaves to your lilacs. Cold snaps dry the leaves out. And the hot scorching sun can burn the leaves. Lilacs need 6 hours of sunlight every day. But if they are exposed to 8-9 hours of sunlight, browning can happen.
Cut the brown parts in this case. And let the new growth take its place.
During the hot summers supply enough moisture. Use organic mulches around the base of your lilac to keep the soil moisture. During winter protect them from the chilly wind.
When your lilac leaves are turning brown you need to find out what is causing it. And then plan out an effective action to treat the problem and prevent it from happening again.
In this article, I have tried to provide all the information on why the lilac leaves turn brown. I hope you found this article helpful in solving the brown leaf problem on your lilacs.
You can apply these treatment measures to any of your lilac varieties such as California lilac, Japanese lilac, Ivory silk lilac, Miss Kim lilac, Texas lilac, Sensation lilac, etc.