9 Reasons For Lilacs Not Blooming [How to Make Bloom]

The amazing fragrance of lilac is what we want. But what if the lilacs are not blooming at all?

Lilacs are very easy to maintain yet their blooming can be a little problem. but where there are problems, there are solutions.

The reasons why your lilacs are not blooming are Wrong Pruning, Lack Of Sunlight, Over Feeding Of Fertilizer, Improper Soil And Water, Disease Infestation, Pests Problems, Cold Damage, Transplant Shock, and Lilacs age.

Your lilacs can overcome these problems with your help. But you have to know what particular issue is bothering your plant. And this article will help you to figure out the case.

So without making any delay let’s get started-

Why Are The Lilacs Not Blooming?[Solution]

1. Wrong Pruning Of Lilac

Lilac’s blooms usually grow on its last year’s growth. They need to be pruned as soon as they have finished flowering. If you prune at the wrong time the lilacs will not be blooming on time.

If your old lilac bush is not blooming you don’t need to worry so much. Because sometimes they bloom every two or three years when they are old.

Control Measure

You have to prune the lilac immediately after they have bloomed in the spring. Lightly prune the oldest branches of lilacs after the spring bloom. If you prune too much the next bloom will be delayed. 

Pruning is also important for providing air and sunlight to the lilac bush. But make sure to finish pruning before midsummer.

2. Lack of Sunlight

Lilacs need at least 6 hours of sunshine to produce nice blooms. If your lilacs are in shade most of the time it can cause them not to bloom.

Control Measure

Provide the lilacs with plenty of sunlight. Make sure other big trees are not blocking the sunlight. If your plants are still young then transfer them to a sunny place. 

Sometimes you need to prune off some branches to let the lower parts be exposed to the sun.

3. Over Feeding of Fertilizer

We often use lawn fertilizers for our lilacs. But too much nitrogenous fertilizer is not good for them. Because nitrogen will produce luscious green foliage but there won’t be many flowers. Lilacs need a light dose of fertilizers every spring.

Control Measure

Phosphorus enhances the blooming rate of any flower. So, Lilacs need phosphorus-rich fertilizer for good blooming. Give your lilacs the best fertilizer that will help the flowering (our pick: Miracle-Gro Shake ‘N Feed Flowering Trees and Shrubs Continuous Release Plant Food)

To supply an extra dose of phosphorus apply bone meal to the lilac’s soil. You can also use well-decomposed manure and organic compost.

Here is a homemade blooming fertilizer recipe that you can make from scratch.

Homemade Blooming Fertilizer For Lilacs


  •  200 gram of any fruit (pumpkin, zucchini, banana, mango, etc.) But avoid citrus fruits. The best combination is Banana: Zucchini: Pumpkin
  • 200 gram of Brown Sugar 


  • Mash the fruits into a paste
  • Now combine with the brown sugar and mix well
  • Keep this mixture in a bowl and cover loosely
  • Let it stay for 7-15 days for fermentation
  • After fermentation, drain the fruit juices.
  •  Store it in a bottle.
  • Add 3 teaspoons of this mixture in 5 liters of water
  • Apply directly to the soil
  • You can also spray it on your lilacs.

4. Improper Soil and Water

Lilacs don’t like too much water. Overwatering can be the cause of why your lilac buds are not opening. Lilacs don’t like wet roots. Even the best-performing lilacs do not do good in constantly wet soil. 

Lilacs like slightly alkaline soil around pH 6-7. So, if the soil is acidic there will be a very low number of blooms. In the case of potted lilac, blooming gets affected if the pot is too small. 

Control Measure

If your lilac is not blooming check the soil water. Check the soil with a moisture meter to have the best watering schedule (Our pick: Atree Soil Soil Tester Kits with Moisture, Light, and PH Test for Garden). Water every week according to the soil moisture and weather conditions. Put a layer of mulch around the lilacs to keep the moisture in the soil.

Make sure to use larger pots for potted lilacs because the roots need enough space to grow. Use a good potting mixture.

5. Pests Of Lilac

One of the reasons why the lilacs are not blooming is pests. Scales and borers attack lilacs and harm the blooms.

Scales look like waxy growth on the stem. And borers are one kind of caterpillar. They are pretty easy to detect. You have to examine the leaves and stems very carefully to find them.

Control Measure

Apply the best and environmentally safe insecticide to your lilacs (our pick: Monterey organic Garden Insect Spray)  at 14 days intervals until the pests are cleared off.

Sometimes scales can infest severely some branches. In this case, it’s best to prune the branches off. Borers attack the sick lilacs very easily. So, keep your plant healthy by regularly doing other management practices.

Check out some easy home remedies for pests that are very easy to make.

#Recipe 1:-Soapy Water Bug Spray Recipe


  • 1 tablespoon of liquid dish soap 
  • 2 liters of water


  •  Mix the liquid soap and water
  • Spray it on your lilacs leaves every week.

#Recipe 1:- Horticultural Oil Recipe


  • 1 tablespoon of liquid soap 
  • 1 cup of any cooking oil like olive oil or vegetable oil. 


  • Mix these ingredients very well 
  • Store the mixture in a bottle for later use.
  • Add a tablespoon of this mixture with every cup of water 
  • Pour it into the sprayer.
  • Spray very thoroughly on your lilacs every week. 

#Recipe 3:- Neem Oil Recipe


  • 1 tablespoon of neem oil 
  • 2 liters of water 


  • Mix the ingredients and spray in the lilacs every week.

6. Lilacs Diseases

Some fungal diseases like powdery mildew, leaf, and shoot blight attack lilacs. And the disease weakens the plants. As a result, the blooming is drastically affected. 

In powdery mildew, the leaves and stems get a powdery white coating. And in blight, the stems and roots get blackened. These diseases are favored by wet and humid conditions.

Control Measure

The fungal diseases need to be cured as soon as you notice them. So pick the best fungicide for your lilacs and start applying according to the label directions (Our Pick: Bonide Copper Fungicide)

You can apply some easy homemade remedies to control fungal problems.

# Recipe 1:-Milk Spray Recipe


  • 300 ml of sour milk 
  • 300 ml of water 


  • Mix water and sour milk together.
  • Use it as an instant mixture. Do not store for later use.
  • Spray it twice a week on your lilacs until the fungal problem is stopped.

#Recipe 2:- Apple Cider Vinegar Spray Recipe


  • 2 teaspoons of apple cider vinegar 
  • 2 liters of water
  • Few drops of liquid dish soap


  • Mix the ingredients very well and spray on your lilacs twice a week.

# Recipe 3:- Baking Soda Spray Recipe


  •  2 teaspoons of baking soda
  • Few drops of liquid dish soap
  • 2 liter of water


  • Mix the ingredients well
  • Spray thoroughly on both sides of the lilac leaves.
  • It’s very effective against powdery mildew

Preventive Measure

Plant your lilacs in a sunny place where airflow is good. Water them at the base and avoid wetting the leaves. If the damage of powdery mildew is severe, prune off some branches.

7. Lilac’s Cold Damage

Sometimes freezing weather can damage the blooms. When the freeze damages the buds, they don’t open. The buds can even fall off from the lilacs. But the good news is, cold temperatures don’t harm the lilac plant.

Control Measure

If you have very cold winters then plant your lilacs closer to any building. This way the lilacs will be protected from cold winds from one side. Cover them with Garden Cover.

8. Lilacs Age

The age of these lilacs can be the reason why they are not blooming. Some of the cultivars take 5 or more years to start producing blooms. Some lilacs are biennial. So, they will flower every second year.

Again some of the new hybrids like “Lavender Lady” and “Korean lilac” start blooming in their second year.

Control Measure

You have to know the age of your lilac. Because if it’s not mature, no matter how much you take care of it the new lilacs will not be blooming.  You have to be patient and keep taking care of it until it reaches maturity.

9. Transplant Shock Of Lilac

When you buy a lilac from the nursery, the plant will need some time to settle into new soil and weather conditions. Shockingly it can even take 2 or 3 years to get established in a new place. Until then it won’t bloom.

Control Measure

If you have just bought a lilac even in the blooming stage, do not expect it to bloom next year. Keep taking care of it with proper water and fertilizers.

How to Get Lilacs to Bloom?

When your lilacs are mature enough to bloom then you can try to speed the blooming by using Epsom salt. This salt breaks the dormancy of lilacs. So, it’s kind of like forcing the lilacs to bloom.

Here is the recipe:

#Recipe 1:- Epsom Salt Solution


  • 50 grams of Epsom Salt
  • 5 liters of water


  • Mix the water and Epsom salt into a bucket.
  • Pour this solution at the base of the lilac plant.
  • Apply this solution once a month during the blooming period

Aside from that you also need to apply phosphorus-rich NPK fertilizer. Water the right amount and Remove the dead flowers from your lilacs. These should do the trick and make lots of blooms.

Frequently Asked Questions (FAQs)

Do Lilac Bushes Bloom Every Other Year?

Usually, the lilacs bloom every year after maturity. But they need proper pruning every year. If they are not pruned correctly the next year’s bloom will be less in number.

Do Lilacs Bloom Twice A Year?

Bloomerang lilac trees bloom twice a year but not all varieties do that. Bloomerang lilacs bloom in spring then after that, they re-bloom in late summer and keep blooming until the frost.

When Do Lilacs Bloom?

Lilacs bloom during the spring. Depending on the variety the time of blooming can vary. Some bloom early in the spring, others bloom in late spring. Some also bloom in summer.

Do Lilacs Need Male And Female To Bloom?

Lilacs are usually self-pollinated. They have both male and female flowers. If you have several lilacs planted together they can be cross-pollinated too.

How Long Does It Take For A New Lilac Bush To Bloom?

Most lilacs take 3-4 years to mature. Then they start blooming. But some varieties can take even 6-7 years to bloom.

How To Make Lilacs Bloom Longer?

The best way is to prune them correctly every year. Remove the old wood and this will produce new blooms next spring. But also lilacs will need enough water and fertilizer on time.


Lilacs are beautiful bloomers but sometimes they don’t flower. If they are not blooming this year, you don’t need to worry. Plan ahead, start taking measures, and prune properly so that they bloom next year. 

All the information in this article applies to French lilac, Japanese lilac, Miss Kim lilac, Donald Wyman lilac, Persian lilac, Common purple lilac, Sensation lilac, and Ivory silk lilac. 

So no matter which variety you have, you can work on them with this information. I hope this article helped you to make beautiful blooms on your lilacs.

This results in the loss of blooms for that year. There is not much that you can do to prevent this; just accept the loss and appreciate next year’s blossoms twice as much.

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