13 Common Marigold Problems and How to Fix Them

Marigolds are a popular flower amongst home gardeners. They are low-maintenance, and provide beautiful blooms for long periods. Grown as an annual, Marigolds do best in warm climates and are quite tough. Although they are quite tough and able to withstand numerous conditions, they aren’t immune to some common plant issues.

Things that are out of our control such as too much rain, bug infestations, or hungry deer are a few things that can harm your marigolds. So what can you do once you see issues start to pop up?

The first step is actually identifying the problem. Once you’ve identified what’s going on with your plant, you can put a plan of action together that will help bring your marigolds back to a happy, healthy state. Let’s take a deeper look at some of the most common marigold problems, and how to fix them!

Wilted Leaves

The first and one of the most common marigold problems is wilting, caused by a few things. The most common reason leaves wilt is that the soil is too dry. If this occurs, increase your watering frequency. It can be tempting to keep your plants moist after seeing wilted leaves, but don’t!

Once they perk back up, simply maintain a consistent and frequent watering schedule. If you keep your plants too moist (especially marigolds that don’t like to be kept moist) you can stress your plant further.

Marigolds will also show signs of wilting when they are experiencing heat stress. This usually occurs in the warmer summer months and has almost nothing to do with moisture. Heat stress occurs when the temperatures remain high and the plant cannot use the water in the soil fast enough to cool itself off.

It can be tempting to water your plants if heat stress happens, but it is important to stick to your regular watering. Soaking heat stressed plants can deprive the root system of oxygen and will further stress your plants out.

A tell tale difference between wilting from lack of water and wilting from heat stress is the color of the foliage. A plant that is too dry will look faded in color and sometimes appear brown or crispy. A plant that is heat-stressed will still have normal dark green foliage.

Floppy Stems or Leaves

The most common reason plants become floppy or lose their turgidity is from overwatering. Plants that are not allowed to dry out in between waterings can become waterlogged causing the stems to appear limp and sometimes lean or fall over.

These floppy stems can hinder the plant from taking up moisture and nutrients properly. Most plants will bounce back from this if given time to adjust. Trim out any damaged areas, and allow your marigolds to dry out in between waterings to prevent overwatering.

Not Flowering

Plants that are not producing flowers usually means they aren’t getting enough sunlight. Marigolds are full sun plants and will take all the sunlight they can get. If your plants are getting too much shade due to location or surrounding plants or trees, this can hinder them from flowering. If your plants are receiving too much shade, move them to a sunnier location.

When your plants are receiving a good amount of sun, but still aren’t flowering, consider deadheading the old blooms. This can promote new growth and will help the plant produce new flowers.

Young plants will not flower until they reach a certain maturity. If you transplant young plants, give them some time to adjust to their new area and mature. If planted in the right conditions, they should flower in no time!

Leaves Turning Purple

Plant leaves turn purple for a couple of reasons. The leading cause is usually a phosphorous deficiency. Marigolds are not super needy when it comes to fertilizer or nutrients, but depending on the soil and other surrounding factors, they can require more phosphorus.

Low night temperatures can also cause these marigold problems. If temperatures dip below 55°F (13°C), your plants can react in many ways. One way is that the leaves will start to turn purple.

If you suspect phosphorus deficiency, apply a fertilizer to your plants. A low grade all-purpose should do the trick if you haven’t fertilized recently or at all. If you have been fertilizing your plants, maybe switch to another fertilizer or find one that provides a good amount of phosphorus.

Yellowing Leaves

Lack of nutrients could be one reason your marigold leaves are turning yellow. Applying a fertilizer will help the coloration go back to normal.

Leaves can also turn yellow due to a disease called Aster Yellows. Aster Yellows affect plants in the Asteraceae family, and cause stunted growth, yellow leaves, and can affect buds and blooms.

This disease is spread by insects that can be found on your plants or weeds surrounding the area. Keep the planting area weed free and keep an eye out for insects all season to prevent these marigold problems.

Brown Stems

If your plant’s stems are turning brown, this can be a sign they are rotting. Oftentimes the rot starts in the root system where too much moisture is being held and will work its way up the plant affecting the main stem first and so on.

This is hard to treat as by the time you see it, the problem has already affected a decent amount of the plant. Make sure you’re planting in fresh, healthy soil to help prevent these marigold problems from occurring. Watering appropriately is another way to prevent rot.

Brown Spots or Leaf Tips

Brown spots can be caused by bacterial leaf spot, or an excessive amount of iron. Marigolds do not grow well in soils that have low pH, and this can lead to iron toxicity. A soil test can help determine if you have a low soil pH.

If the spots seem more sporadically located, they are likely caused by bacterial leaf spot. Treat leaf spot with a fungicide.

Leggy/Stretched Out Stems

Plants become leggy when they aren’t getting enough sunlight. Marigolds grow best in areas that receive full sun, as much as they can get. If your plants are in an area that is receiving too much shade or just not enough sunlight, the plant will become leggy and look stretched out as it is reaching for more light.

Be sure to rotate potted plants to ensure they receive even sunlight. Transplant-shaded plants into a new sunnier location and they will soon adjust to normal growing patterns.

Gray Powdery Leaves

In conditions where humidity is high, or plant leaves aren’t allowed to dry out and get good airflow, Powdery Mildew can form. Powdery Mildew is a fungus that appears as a sticky white substance on the tops of leaves.

It often occurs on older growth where leaves are more bushy and close together, but can affect new growth in certain conditions. It is important to eradicate this fungus as soon as possible as it can do a number on the host plant and spread to your other plants.

There are home remedies that can help prevent the spread of Powdery Mildew, but if it is severe a fungicide application might be necessary. Copper soap or fungicides with sulfur as an ingredient seem to be the most effective.

Speckling on Leaves

Yellow or brown speckling on leaves is usually caused by a bug infestation. Aphids or spider mites are usually the culprits on flowering annuals such as marigolds. Aphids appear as tiny green insects on the undersides and stems of plants.

They feed on foliage, creating a brown-speckled appearance. Since aphids have such an extensive life cycle, it is important to treat them accordingly so these marigold problems don’t get out of hand.

Spider mites are tiny white bugs that will create small webs that look similar to normal spider webs. They create a sticky substance across the plant and will feed on foliage which will create a yellow speckling on the leaves. Spider mite infestations start small but can increase quickly. Pyrethrum sprays are a good option for eradicating spider mites.

Black Spots on Leaves

Small black spots can appear on the tops of the leaves. This is generally unsightly and can become a nuisance if the condition worsens. Remove affected plant leaves to clean the plant up and help prevent further spread. A fungicide application should eradicate the problem.

Curly or Distorted Leaves

Distorted leaves are another symptom of the disease Aster Yellows. Aster yellows will often be accompanied by other symptoms such as distorted buds and blooms, and yellowing of leaves.

Curly leaf growth is often caused by foliage-sucking insects such as aphids. Aphids are usually found on the undersides of leaves and can be present all throughout the growing season.

These tiny green insects latch onto leaves and stems and can kill your plant if the problem is severe. Blast your plants with a strong stream of water in the morning to knock them off the plant. An insecticide that contains pyrethrum or spinosad soap can kill aphids effectively.

Holes in Leaves

Leaves that have holes in them or parts of the leaves are missing completely mean something is probably eating them. Japanese beetles can do a number on plant leaves and will destroy an entire plant if given the chance. Slugs and snails can also chew on leaves leaving parts missing.

It can be hard to determine if snails or slugs are the culprits of these marigold problems as they come out at night and hide in cooler spots during the day. The easiest way to tell if you have a slug or snail problem is to keep an eye out for the white slime they leave behind.

Japanese beetles are fairly large beetles and are shiny green and black. They make fairly large holes in plants and are usually easy to spot. You can pick them off if you catch the problem early, but if there are a lot of them you might benefit from using a spray.