Why Are My Sunflower Leaves Turning Yellow? Cause and Solution (2023)

We appreciate sunflowers for their beautiful hue. Succulent and flower gardeners alike love this plant for its vibrant hues. In addition to the yellow, brown, and greenish tints they promote, these blossoms are a visual treat for shrub fans. 

Unlike most other plants, sunflowers often undergo dramatic changes in their appearance when confronted with new challenges. This discoloration seems to be caused mostly by stress, according to the specialists. Succulents, on the other hand, change color when they perceive a shift in their environment. Heat and bright light must be taken into consideration in this case.

Finding out why are your sunflower leaves turning yellow – the plant’s method of expressing that it is in danger or possibly dying – is going to require some investigation on your side. 

Overwatering, nutritional imbalance, lack of space, and other factors might be at blame. We explore the root causes of this undesirable development and how to correct them so that your sunflower may continue to thrive.

Medicines may be swapped between sunflower leaves, which is a frequent practice. Aside from that, discoloration may be caused by many other things.

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Why Are My Sunflower Leaves Turning Yellow?

It’s time to get to the bottom of why your plant is turning from green to yellow or purple. You’ll also get some guidance on how to care for your plant.

1. Is the sunflower receiving the nutrition it requires?

A plant’s health might be jeopardized if it doesn’t get enough of the proper nutrients. It is important to provide the soil with the proper nutrients/fertilizer for the sunflower to grow strong and healthy, despite the fact that sunflowers do not typically need fertilizer.

Nitrogen has to be the most critical nutrient for sunflowers. The stem becomes brittle, the leaves become yellow, and eventually, the plant dies when nitrogen levels are too low. Adding an excessive amount of nitrogen to the soil might cause the sunflower to produce fewer flowers but more leaves, so use caution.

2. Is your sunflower receiving an excessive amount of water?

Even though sunflowers enjoy moisture, there comes a point at which the earth surrounding them gets submerged in water, particularly if the soil is poorly drained. Sensitize the area surrounding your sunflower plant’s base. If it’s flooded, you’ve got issues.

Scrape over the top topsoil and include some dust and biogenic matter/compost to aid with drainage. Additionally, this helps the soil retain the proper quantity of water and provides nutrients to the base of the plant. 

Additionally, minimize the amount of water you feed the plant. Sunflowers that have been seeded need constant watering around the root zone until the soil is saturated to a depth of a few centimeters.

Sunflower leaves turning yellow
Sunflower leaves turning yellow

3. Is the sunflower suffocating?

Every plant needs room to thrive and proper air circulation around its stems and leaves. Sunflowers have deep roots that must be able to expand quickly. If rocks or other lateral roots obstruct their development, the plant’s development may become restricted, and the foliage may lack the energy they need to stay green. This leads to yellow leaves, among other symptoms.

Additionally, if your sunflower is competing for moisture and nutrients with other plants, it may not obtain what it needs in the first place. Yellow leaves might be the outcome once again.

Ascertain that there is sufficient space over the surface around your sunflower and that its stem is not squeezed by the roots of other plants. If it is, either relocate it to a more open spot or thin down some of the surrounding plants.

4. Do the fading leaves have brown or black spots?

Obviously, this is terrible news, as it implies that the plant is most likely suffering from a fungal infection, rot, or mold. You must take urgent action in order to resolve this situation. The most prevalent sunflower illness is Verticillium Wilt, which is caused by a fungal virus that is just a few microns in size. 

The infection begins with the yellowing and browning of the leaf surface between the veins, followed by the withering and drying out of the foliage, and eventually the death of the plant.

Remove the contaminated leaves from your yard and do not place them in your composter. Make sure to keep a watch on the plant since, if the fungus has found its way into the stem of the plant, it has the tendency to escalate to the other leaves.

5. Is your sunflower overgrown or an antique?

Even if you don’t uncover any of the indicators we’ve provided here in your plant, it’s possible that your sunflower foliage is turning yellow since the plant is becoming older. 

Sunflowers are no different; as they mature, their color fades and their heads become brown, at which time they may be picked.

There are some other reasons that make sunflower leaves go yellow or brown. Those reasons are listed below: 

6. Deficiencies in Nutrients

Sunflowers often suffer from nitrogen and phosphorus shortages. Nitrogen-deficient plants might well have yellow foliage that retains its green color along the veins. 

Those deficient in phosphorus, on the other hand, may yellow or acquire a purplish or reddish tint. Before applying fertilizer, check the pH and fertility of the soil, since other issues are likely present. 

7. Yeast or Fungal Rots

It is fungal that causes the damage.

A lot of the time, fungal rots happen when plants are struggling in soil that is too wet, either because there isn’t enough drainage or because they’ve been overwatered for too long. 

Early signs are usually limited to foliage that looks dull or turns yellow all of a split second. Take care of infected sunflowers quickly because they can propagate to other plants that haven’t been influenced.

8. Mites seen on spiders

Mites are tiny invertebrate animals that feed on plants and are hard to notice without a magnifier. They, like aphids, suck liquids straight from leaf tissue, generating subtle shading on foliage that gradually becomes golden, yellow, or brownish in hue. 

The tiny webs spun by these pests as they eat may aid in distinguishing their damage from that caused by other sources of leaf yellowing. 

Pesticides are inefficient for fighting mites, and they may induce demographic expansions by killing the predators that eat these arachnids. 

Solution For Why Succulent Leaves Turning Black

Solution to the Sunflower Leaves Turning Yellow

Here are a few pointers to keep your sunflower leaves from turning yellow:

1. Adequate Watering

Since sunflowers are resistant to both dryness and temperature, plants do need to be watered on a regular basis. The entire root area, which is around 3–4 inches from the base, would need to be hydrated as it grows. 

The dirt around sunflower seeds should be damp but not drenched every day. Sunflowers may be watered once per week after they’ve developed themselves. 

When you do water, make sure to use a few gallons of water to ensure that the soil is adequately moist.

2. Using Fertilizers

When your soil is deficient in nutrients, you need to fertilize your sunflowers. 

Consider using a sluggish fertilizer or manure to help remedy this situation. Avoid giving any too near to the plant’s root system.  

If you add fertilizer to the soil that is already robust, you run the risk of producing an excessive amount of nitrogen, which may damage roots or hinder flowering.

3. Removing Weeds and Bugs

Sunflowers attract slugs, snails, birds, squirrels, and deer. Repellents help deter slugs and snails. Birds and squirrels like sunflower seeds, so drape them with poly spun horticultural fabric. 

Construct a thick security fence around the garden to keep deer out. Too much moisture causes yellowing and shrinking of sunflower leaves. 

This fungus thrives on clay or damp soil, preventing flowering. Eliminate diseased leaves and limit watering.

4. Securing big trees

Bigger or multi-branched sunflowers often require support. Bind drooping sunflowers to a post or solid base. This is also required for flowers in windy areas.


If your seedlings are consistently withering or discolored, you may be over or under-watering them. Or it might be too hot. Water the plants once the dirt is absolutely dry. Move the bucket, next water it carefully.

If the issue is nutrient deficiency, buy a fertilizer with macro and micronutrients. Homemade fertilizer may be made in numerous ways. The plants receive all they need from compost.

Once sunflowers are pleased, they blossom profusely. Eliminate the unwanted dead flowers and they’ll thrive. So the plant grows quicker. You may also pluck useless dead branches. If you live in a chilly climate, you might have to bring the plants indoors. Winter normally kills sunflowers.

Thank you for stopping by! Hope this article helps you point out the issues of your yellowing leaves. Make sure to follow the guideline for improvement in your plant.