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 can be 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 out further.
Plants 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 themselves 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 sign between wilting from being dry and wilting from heat stress or overwatering 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 overwatering or heat-stressed will still have normal dark green foliage.
Tips of leaves begin to turn dark brown when the plant has been overwatered. It usually appears on the tips of leaves but can also affect stems. Whole leaves can begin to turn brown and get crispy, eventually falling off.
Remove the affected leaves and allow your plant to slightly dry out before watering again. Once the plant has begun to dry out, return to a consistent watering schedule. Marigolds do not like to be kept too moist, so keep this in mind when watering your plants.
African marigolds, with their vibrant colors and cheery blooms, are a beloved addition to many gardens. However, their beauty can be marred when the leaves begin to curl, twist, and contort. As an avid gardener and African marigold enthusiast, I’ve seen my fair share of curly leaves and have gotten to the root of what causes this frustrating issue. In this comprehensive guide, we’ll explore the various factors that can cause leaf curl in African marigolds, from environmental stressors to pests and diseases. I’ll provide actionable tips to remedy curling leaves, prevent future occurrences, and keep your African marigolds looking their best all season long.
Environmental Causes of African Marigold Leaf Curl
African marigolds are sensitive plants that can show signs of stress, including curled leaves, when growing conditions are less than ideal. Here are some of the most common environmental factors that can lead to leaf curl:
Extreme Temperatures
African marigolds thrive in moderately warm temperatures between 65-75°F. Prolonged exposure to hotter or colder temperatures can put stress on the plants. In very hot conditions, leaves may curl up to reduce water loss. Frost or cold snaps can also damage plant tissues, causing distorted leaves.
To prevent temperature-induced curling, provide shade cloth or row coverings to protect plants from intense sun and extreme cold. Avoid large day-night temperature fluctuations.
Improper Watering
Inconsistent watering often results in leaf curl in African marigolds. Underwatering causes leaves to curl inward to conserve moisture. Overwatering can lead to root rot and damaged roots are unable to take up water properly, resulting in leaves curling due to drought stress.
Water African marigolds regularly when the top 1-2 inches of soil become dry. Provide 1-2 inches of water each week, adjusting for rainfall. Ensure proper drainage.
Low Humidity
African marigolds prefer 40-50% relative humidity. In drier environments, the leaf edges may curl or roll inward to prevent moisture loss. Grouping plants together can create a more humid microclimate. Mist foliage regularly to increase humidity.
Wind Damage
Strong winds can batter and damage African marigold foliage, causing leaves to appear torn or curled at the edges. Provide shelter from wind stake tall plants and avoid handling leaves when windy.
Poor Soil Conditions
African marigolds need well-draining soil with a pH between 60-75. Poor drainage can lead to root rot and curled leaves. Acidic or alkaline soils can make key nutrients unavailable for proper growth and leaf formation.
Pests & Diseases That Cause African Marigold Leaf Curl
A variety of pests and pathogens can attack African marigolds, causing distorted and curled leaves. Be on the lookout for these common culprits:
Aphids
These tiny sap-sucking insects feed on plant juices and leave behind sticky honeydew, causing leaves to curl and twist. Use insecticidal soap, neem oil, or release ladybugs to control infestations.
Spider Mites
Nearly invisible to the naked eye, spider mite feeding causes stippling, discoloration, and eventual curling of leaves. Knock them off with a strong spray of water or use sulfur dusts.
Whiteflies
Whiteflies congregate on the undersides of leaves, sucking plant sap. The leaves turn yellow, shrivel, and curl upwards. Use yellow sticky traps and insecticidal soap to control them.
Powdery Mildew
This fungal disease coats leaves with a white, powdery substance. It thrives in high humidity and causes leaves to twist and distort as it spreads. Improve air circulation and use neem oil to prevent and treat it.
Alternaria Leaf Spot
Brown/black spots that form on leaves can expand and cause curling. Avoid overhead watering, space plants properly, and remove diseased foliage promptly.
Nutrient Deficiencies That Lead to African Marigold Leaf Curl
African marigolds are hungry plants with needs for macro- and micronutrients. Deficiencies cause a range of symptoms, including leaf curl:
Nitrogen
Nitrogen deficiency causes overall yellowing and pale leaves that eventually curl inwards from the tips as resources are focused on new growth. Use a balanced fertilizer higher in nitrogen.
Phosphorus
Without enough phosphorus, leaves may turn purplish and begin curling under as flowering and root growth suffers. Apply bone meal or rock phosphate.
Potassium
Curling leaf edges and tips combined with spotting and chlorosis point to potassium deficiency. Add potash or wood ash to replenish soil potassium.
Calcium & Boron
Lack of calcium and boron leads to distorted leaf tips and margins curling in strange shapes. Foliar sprays containing both nutrients can help.
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.
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 containerized plants to ensure they receive even sunlight. Transplant-shaded plants into a new sunnier location and they will soon adjust to normal growing patterns.
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.
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 they 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.
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. Allow your marigolds to dry out in between waterings to prevent overwatering.
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.
If 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!
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 leaves to turn purple. If temperatures dip below 55, 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.
Leaves turning yellow can be caused by a few different things. 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.
Marigolds do not like to be kept in moist conditions. Allowing your plant to dry out in between waterings can help prevent certain problems from arising such as stem and root rot.
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.
Applying a fungicide can help stop this from destroying your plants, but if the problem has already affected a decent amount of the plant, it might be too late. Make sure you’re planting in fresh, healthy soil to help prevent this problem from occurring.
Marigold Leaves are Curling? Causes & How To Treat Leaf Curl
Why are my African marigolds turning yellow?
These diseases are often spread by insects such as aphids or through contaminated tools or plant material. Identification: Symptoms of viral diseases in African marigolds include yellowing or mottling of leaves, stunted growth, distorted flowers, and overall poor plant vigor.
What causes dark spots on African marigold leaves?
Leaf spot is another common disease that affects African marigolds caused by various fungal pathogens. It appears as dark spots on the leaves of the plant and can spread rapidly if left untreated. Identification: Look for circular or irregularly shaped spots on the leaves of the African marigold plant.
What are the most common marigold problems?
Let’s take a deeper look at some of the most common marigold problems, and how to fix them! One of the most common causes of wilted leaves is too dry soil. Wilted leaves can be 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.
What diseases affect African marigolds?
One of the most common diseases that affect African marigolds is powdery mildew. This fungal disease appears as a white powdery substance on the leaves, stems, and flowers of the plant. Powdery mildew thrives in humid conditions and can quickly spread from plant to plant.