Sunflower Petals Falling Off? (7 Problems + Solutions)

Sunflowers are a great deal to the gardeners because of their divine aesthetic beauty and vibrant yellow color. However, sadly, this beauty doesn’t last forever. Due to some issues, their petals keep falling off and the plant eventually loses all its glory.

But if you are not ready yet to say goodbye to these yellow sunshines you have to take some necessary action before the time runs out.

Luckily, I am going to talk about why the sunflower petals are falling off and how you can save them. But before that, you have to know what are the exact reasons behind this.

The sunflower petals can fall off due to:

  • Natural causes
  • Nitrogen deficiency
  • Imbalanced watering
  • Improper root structure
  • Attack of pests
  • Infestation of white mold 
  • Too much heat

In this article, we are going to cover all the above points and explain what steps you need to take so that you can help your sunflowers to stay strong and grow their petals back in the next season.

But before getting into the article let’s check out the problems and their solutions at a quick glance:

Problems Control Measure
Petals fall of naturallyCover the sunflowers with a screen to protect the seeds from insects and birds.
Nitrogen deficiency Apply a slow release granular fertilizer that contains high doses of nitrogen.
Improper root development Use light textured sandy loam soil.
Imbalanced watering Use 7-8 liters of water for each full grown plant every week.
Pest attackUse an organic pesticide from time to time.
White mold infestationUse a good fungicide until you get rid of the mold.
Too much heatProvide some shade during the hot parts of the day.

Why Are My Sunflower Petals Falling Off (Explained)

1. The Petals Fall of Naturally

If your sunflower’s petals have started to fall off after one or two weeks of blooming then you have nothing to worry about because this is a very natural process for them.

The thing is, after blooming the sunflowers don’t last much long and you’d be surprised to know that after around 18-20 days all of the petals will start to fall.

This is because, after the pollination, the seeds start to grow and this growth deliberately pushes the petals outwards. Moreover, after the bud formation, the flowers become unable to follow the sun and as a result, the petals start to droop and fall off.

Eventually, all of the petals will drop down leaving only a cluster of seeds in the shape of a ball on the stalk.

Control Measure:

Since this happens totally due to their natural life cycle, you cannot have any control over it. What you can do is salvage what is left of it. 

In this case, when the petals are falling off you can cover the sunflowers with some screens or nets to protect the developing seeds from the damage of birds and harmful insects.

When the flower dries and all the petals fall out completely, you have to look at the head closely. If the head seems to have turned yellow then it’s the right time to cut them off. But remember to keep at least 10-12 inches of the stalk along with the flower head.

If there are any petals left, get rid of them and get the seeds out by rubbing and pushing the seed out of the flower. While rubbing also look out for the pest-infested seeds and throw them out. 

After taking all the seeds out, dry them under the sun very thoroughly and then you can store the seeds to use for planting another batch of sunflowers. Also, you can use the seeds to cook many mouthwatering dishes.

2. Nitrogen Deficiency

Nitrogen is a vital nutrient for the sunflower and when they are deficient in this nutrient the rate of photosynthesis drastically decreases. 

As a result, the amount of food produced in the plant becomes insufficient to carry on the growth and development of the flowers. Eventually, the leaves start turning yellow and the sunflower petals start falling off. 

Control Measure:

When the sunflower plants are growing you have to make sure the soil has enough nutrients to keep providing them with the extra need of food in order to produce large and healthy flowers. This is why you have to apply fertilizers in soil before sowing the seeds to get them a boosted start.

Again, during the vegetative phase apply a slow-release granular fertilizer that has a good amount of nitrogen and a balanced dose of other macro and micronutrients.

However, refrain from applying nitrogenous fertilizers after the flowers have started to bloom as it can affect the growth of the flower. 

One important thing is always to use fertilizers when the weather is cool, which is mostly during the morning periods. Otherwise, if you fertilize your sunflowers during the scorching sun period, the leaves will get “fertilizer burn”

3. Imbalanced Watering

When it comes to watering, sunflowers are very delicate plants and they usually need plenty of water in order to produce large flowers. However, sadly both overwatering and underwatering can cause their petals to fall off.

When the sunflowers are underwatered, naturally the leaves and flowers will get dehydrated and the petals will start to droop down. 

On the other hand, Sunflowers don’t like their roots to stay wet so over watered soggy soil is not the best choice for them.

Again when they are overwatered the sunflower plants will get infected very easily by root rot and this disease will result in wilted and leggy plants. At the same time, the plant will be losing a lot of leaves and petals too.

Control Measure:

Since watering seems to be difficult for the sunflowers, a grower always has to be alert. During the dry weather water them enough to soak the top few inches of soil.

A well-grown sunflower plant usually requires 7-8 liters of water every week. So you can start watering them every day moderately at first and then as they grow you can increase the watering to meet the above mark. 

To prevent the chances of overwatering try to water them frequently in small amounts so that there is no chance of a water logging situation.

But if the weather is cool and the soil is not that dry, then water enough to soak only 2 or 3 inches of the soil every other day. 

Apart from that make sure that potted sunflowers have large enough holes to drain out the excess water quickly. Also, water your both potted and garden sunflowers plants during the early morning.

And never water them during the hot afternoon periods as they can burn the leaves.

4. Improper Development of Roots

If the roots are weak and under-developed then you cannot expect your sunflowers to thrive. Due to weakly developed roots, the plants become unable to uptake enough water along with all the necessary nutrients for themselves.

As a result, the plant produces poor-quality flowers and moreover, the petals fall off much sooner than their usual time of natural petal drop. 

Control Measure:

Usually, compact soil causes this issue as it doesn’t give the roots enough space to grow and breathe properly. They thrive in sandy loam soil whereas clay soil creates waterlogging conditions for them.

So if this is the case for you then change the soil as soon as possible. You can mix some sand or perlite with the soil to facilitate better root penetration.

Sunflowers are tolerant to tough situations though they prefer to be in a soil that has a pH level of 6 to 7.5. So check the pH of your soil and adjust it within this range by acidic fertilizer (if the pH is higher than 7.5) or lime fertilizer ( if the pH is lower than 6)

The choice of the right soil is important because If you are growing the sunflowers in a pot then the wrong kind of soil will rapidly cause your plants to wilt and die. Make sure to use a good potting mixture that is light and quickly drains out water.

5. Pest Attack

Sometimes borers, caterpillars, cutworms, Japanese beetles, and some grasshoppers can cause the petals of your sunflowers to fall off very quickly. These insects feed on the leaves and fleshy stems of the plant. 

This lowers the photosynthesis rate which mainly makes the sunflowers malnourished and eventually the leaves and petals drop off.

There is also one kind of moth called the “sunflower moth” that loves to lay eggs on the flower heads. Eventually, the larva grows and starts to feed on the sunflower seeds and petals and causing some serious damage. 

Control Measure:

To get rid of the harmful bugs you can spray a good quality organic insecticide when you see a noticeable number of insects on your sunflower plant. The organic products are also safe for the environment and equally effective in killing pests.

Sometimes you can also use a hose and water the sunflowers with a good flow. This will also kill off some soft-bodied small insects.

However, hosing down the plant will not provide any permanent solution. You can also handpick some large beetles and caterpillars.

You have to clean all the weeds around your sunflower plant and make sure they are not crowded in one place. Because the insects are attracted to weeds and crowded areas. 

To prevent the insect attack you can plant the sunflowers from late June to early July because at this time insect infestation gradually decreases due to environmental reasons.

In addition, to prevent any pest attack, before adding any new plants to your garden you have to keep it isolated for some time to observe.

Because it can contain insects hidden under leaves or other floral parts which can infest in your garden. So, after a period if you find any insects treat the plant with insecticides and then add it to your garden.

You can use soapy water which also works great against Japanese beetles. In addition, neem oil works amazingly as a natural insecticide that not only kills insects but also protects the sunflowers from many fungal diseases.

And the best thing about the neem oil is it has no side effects and you can use it as a preventative measure against pests. 

Neem Oil Spray Recipe:


  • A  gallon of water
  • 2 tablespoons of neem oil
  • 1 teaspoon of mild liquid soap
  • One-third teaspoon of aloe vera powder (optional)


  • First, mix the neem oil and liquid soap very thoroughly into a creamy paste.
  • Then add half a liter of water at first and combine well.
  • After that add the rest of the water.
  • Now the neem oil solution is ready, you just have to pour it on a spray bottle and start spraying on both sides of your sunflower leaves and petals.
  • While spraying, keep shaking the spray bottle frequently.
  • As the solution is an emulsion so it sits out after some time so always make a fresh batch by adjusting the ingredient quantities as you require.

6. White mold

There are some diseases that attack the sunflower and white mold is one of them. Though the disease is not deadly to the plant, it surely causes a layer of white fungal growth that turns the petals into white, and ultimately they fall off. 

Moreover, the plant loses its aesthetic beauty and the rate of production of seeds is drastically reduced.

Control Measure:

To get rid of the white mold you have to use a good quality fungicide on your sunflower plants by spraying it carefully on both sides of the leaves and petals.

Also, you have to make sure that your sunflower plants have enough space between themselves to ensure better air circulation. For this, always sow the seeds 2-3 feet apart from one another for optimum plant spacing.

You can also try some homemade remedies that have antifungal properties such as baking soda spray to keep the mold growth in control. The recipe is given below:

Baking Soda Spray Recipe:

ingredients :

  • ¼ tablespoon of baking soda
  • 1 liter of water
  • ¼ teaspoon of liquid mild dishwashing soap


  • Mix all the ingredients thoroughly and then pour the solution into a spray bottle 
  • Spray it over the white mold covering both sides of the leaves and petals, even stems.
  • Spray in the morning so that plants are not stressed under the hot sun.
  • You can spray this solution every other day as long as it is necessary.
  • Never store this solution and always make a fresh batch before use.

7. Too Much Heat

We all know that sunflowers love to soak themselves in the sunshine. But they too have a limit for it. When too many hours of scorching sunlight along with high spells of heat waves occur, the sunflowers start to lose their petals due to environmental stress.

Control Measure:

When the temperature usually goes above 35 °C the sunflowers start to feel stressed. As a result, the plant starts to wilt and lose its leaves and petals. 

To avoid this issue you can use a shaded screen to prevent the sunflowers from getting excessive heat and sunlight during the hot parts of the day.

If you are growing them indoors then occasionally use a fan to reduce the heat around the plant.


How Do You Know When a Sunflower Is Dying?

If the sunflower is dying then firstly the plant will completely stop growing and the leaves will turn yellow and gradually start to fall off. Moreover, the leaves that are in the plant may turn black or brown. Aside from that, the plant will start wilting and the stem will be very leggy and break at some point and ultimately die. 

Will The Sunflower Petals Grow Back?

Well, there are two types of sunflowers. The ones that are annual will not grow their petals back but the perennial ones will shed the petals and during the next season, the petals will grow back naturally. 


There are a lot of reasons for your sunflower petals to fall off. Meanwhile, all of these reasons have their own solution. So, you have to closely observe your plant and figure out exactly what problem it is facing, then everything will be a piece of cake for you. 

I hope this article helped you to find out the signs of stress on your sunflowers and guide you to their correct fix.

For any further queries drop your question in the comment box below and we’ll get back to you soon.

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