8 Reasons Your Cyclamen Plant Has Yellow Leaves
Cyclamen plants may end up with yellow leaves for a variety of different reasons. And each reason may end up having a slightly different treatment plan, depending on the cause. In this article, gardening expert Emily Horn looks at the most common reason your cyclamen plants have yellow leaves, and how to fix it.
Florist cyclamen makes a dazzling houseplant often given as a Christmas gift. It is fairly easy to grow, but when the leaves start to yellow and fade, the plant loses its aesthetic luster.
As with all houseplants, cyclamen does not always adapt perfectly to indoor conditions.
Yellowing or sick-looking leaves are likely a sign that this Mediterranean species needs some extra care. Here are the 8 most common reasons cyclamen leaves turn yellow, plus how to prevent and fix them.
The Short Answer
Yellow cyclamen leaves can be caused by excess heat, improper watering, dormancy, or insect pests. Leaf discoloration can be prevented by providing a temperature range between 50℉ and 70℉, maintaining moderate moisture, and keeping plants pest-free.
The Long Answer
Any houseplant’s native habitat offers clues to its ideal conditions. The genus Cyclamen is composed of 23 different species found throughout the world. The most popular in the U.S. is Cyclamen persicum, commonly known as the florist’s cyclamen or Persian cyclamen.
As a member of the Primulaceae family, these plants are normally found living in rich, well-draining soils. They typically grow in a protected spot under large plants where they receive indirect sunlight that trickles through its taller neighbor’s leaves.
Cyclamen persicum is native to the greater Mediterranean region, particularly in Palestine, Lebanon and Syria. This climate is known for hot, dry summers and cool, wet winters ideal.
While it is often grown as a houseplant, florist’s cyclamen can be grown outdoors in USDA hardiness zones 9-11. It tolerates temperatures as low as 30 to 40℉.
What Causes Cyclamen To Go Dormant?
Cyclamen tends to go dormant during periods of dry, warm conditions. This occurs because, in its native Mediterranean habitat, plants must protect themselves from hot, drought-stricken summers.
Typically, they break dormancy in early fall. As temperatures cool, they send out their signature green, heart-shaped leaves and flower spikes of various shades like red, purple, pink, and white. This makes Cyclamen a perfect plant for gift-giving on Christmas and Valentine’s Day.
8 Reasons for Yellow Cyclamen Leaves
Yellow leaves are a plant’s way of communicating that something is not right. If your houseplant is looking unsightly, here are some potential causes and solutions.
Cyclamen prefer to stay at air temperatures between 50℉ and 70℉. If the temperature consistently stays above 70℉, it may go dormant, beginning with its leaves turning yellow.
Researchers have found that cyclamen goes dormant during dry summer months to protect its tuberous roots.
If your cyclamen appears to start dormancy at a time other than late spring or early summer, check how much sunlight the plant receives. As you know, the sun provides both light and heat, and the it may need to be relocated if it is exposed to an extra hot windowsill.
Another possible reason for forced dormancy is placement near a heater or furnace vent. Too much warmth is a trigger for dormancy, so consider moving your plant away from heat sources.
Is it possible to overwater a plant that prefers to live in a moist soil environment? Yes!
Moist does not mean soggy. Few plants can survive with soggy soil, particularly if they are from the rocky soils of the Mediterranean.
If a cyclamen is living in a pot that has no drainage, the potting mix can quickly become oversaturated. Waterlogged soils prevent oxygen from getting to plant roots, which ironically inhibits the absorption of water and nutrients by the roots.
The leaves will begin to yellow. Because of the excess water, leaves can also become limp and fall over.
One way to prevent overwatering is to only water when the plant needs it. Unfortunately, your plant isn’t going to speak to you and ask for a drink.
If you are unsure as to whether or not to water your cyclamen by looking at the soil, stick your finger into the soil and see how wet it is down where the root zone is. This is one of the best ways to determine if watering needs to take place.
- Is it dry deep down in the soil? Your finger will come out chalky or dusty.
- Damp? Your skin may have some soil on it.
- Soggy? The soil will look like brownie batter on your finger.
When you water, avoid getting the crown wet as much as possible. Excess moisture on the crown can cause the stem to rot, resulting in a total plant collapse.
For most plants, it is easier to recover from being underwatered than from being overwatered. But, you need to make sure that you are providing adequate water for plant growth, while avoiding overwatering.
Cyclamen thrive under cool, moist conditions. If not given enough water, the leaves will become yellow. Instead of looking droopy, as shown in overwatering, the leaves will become crunchy. This may force the plant into premature dormancy.
If not enough food was produced during the time it was actively growing prior to drying out, there may not be enough food available in the stem to break dormancy once watering has resumed. This will result in a dead plant.
Give your cyclamen a generous drench until water pours out of the bottom of your container. If growing outdoors, stick your finger 4-6″ deep in the soil and check the moisture.
After a long period of drought-like conditions, check the plant every few days to ensure it is perking up. You can remove dead leaves and look for newly emerging leaves after a few weeks.
Given the dramatic winter display outdoor plants show while preparing for dormancy, it is sometimes difficult to see the subtle clues our houseplants show when preparing themselves for a long-needed rest. One of the ways indoor plants indicate pending dormancy is by the leaves beginning to change color from green to yellow.
Cyclamen are cool-season plants, meaning they like to grow during the cooler, moister times of the year. They rest during the dryest, hottest months. These behaviors mimic the changes in the environment of the Mediterranean desert perfectly.
This is another reason why we find cyclamen lining the store shelves during the holidays well into mid-February. The colder temperatures and decreased day lengths are perfect for growing cyclamen.
Once days begin to get longer and the temperatures increase, they begin to slow down their growth. As a cyclamen enters dormancy, the leaves begin to produce less and less food for the plant. Eventually, food production will cease, and the leaves turn yellow and dry up.
Since the cyclamen is no longer growing, it is important to cease watering. The remaining stem, or crown, will look dead; but should be firm to the touch. If you water this crown while dormant, you risk overwatering the plant and causing the crown to rot.
After a few months of rest, your plant will show signs of life again. Most likely, you’ll see leaves emerging from the crown. When this happens, begin watering as usual.
Cyclamen mites are difficult to detect. These eight-legged arachnids are very small and commonly missed by the naked eye. Their bodies are oval in shape, often resembling small spiders.
Cyclamen mites have piercing-sucking mouthparts, so they prefer soft, younger plant tissues to tough, older ones. The mites prefer to live on leaf, stem, and flower bud tissues, so often, there are little to no outward symptoms of an infestation.
Unfortunately, under the right conditions, these mites can complete their life cycle (from egg to reproducing adult) in as little as ten days. Given the short amount of time to reach maturity and the ease of reproduction, mites become pests in a hurry.
Once populations have boomed, you may notice chocolate brown, corky areas of growth found on the underside of leaves. Other symptoms include:
- Yellow leaves
- Curling of the leaf margins
- Stalks that collapse
- Flowers that fail to open, drop prematurely or bloom below the leaf canopy
Unfortunately, cyclamen mites are very difficult to control. If you suspect you’ve got a cyclamen mite infestation, it is wise to discard damaged and severely-infested plant materials entirely.
Some pesticidal sprays, such as neem oil, may be used to slow their spread by smothering eggs on the plant parts.
Aphids are a common pest to many plants, and cyclamen are not immune. These bugs will insert their piercing/sucking mouthparts into the soft, supple tissues of new growth and literally suck the juices from inside. Aphids are true insects, having six legs, a teardrop-shaped body, large eyes, and what looks like a tailpipe structure protruding from the end of its abdomen.
These tailpipes are called cornicles. This is where the syrup-like excrement is expelled, resulting in a sticky surface on the top of leaves below the aphid colony. Aphids can come in green, yellow, pink, black, and brown. They also sport a set of wings when mature.
Even though the mouthparts are the same as the cyclamen mite, aphids hang out in highly visible locations. Since they prefer young tissue, you will find aphids on the tip of shoots in clusters hanging from the plant. Other times, you will notice white castings on the underside of leaves that blow, not fly, in the wind if disturbed. These castings are the dead skin from the molting process.
Damage caused by aphids can resemble wilting. Check the potting soil to make sure the plant is adequately watered. If the plant is not dry, examine the new growth for aphids or other sucking insects like scales.
If you find aphids, you must start treating your cyclamen ASAP. Aphid populations can skyrocket overnight, causing substantial damage to your cyclamen as well as other houseplants you may have.
Insecticidal soaps and horticultural oils are very effective in controlling aphids on houseplants. Be sure to read the pesticide label prior to application.
If you find yourself without any chemical sprays for aphids, you can make your own spray using water, dish soap and cooking oil:
- Fill a quart-sized spray bottle with water.
- Add two drops of dish soap and 1 tsp. of cooking oil to the spray bottle.
- Shake thoroughly.
- Spray your plant with the mixture to the point of runoff, meaning the mixture runs off the leaf surface and down to the leaf underside and stem.
Another option is to take the cyclamen outside and let natural predators feast upon the aphids. As long as the outdoor temperatures are above 50 degrees, you can safely place your cyclamen in a semi-shaded location outside.
It never ceases to amaze me how quickly beneficial insects like lady beetles, lacewings, and parasitic wasps can hone in on an aphid colony and devour the pests within a few days.
Mealybugs are not picky about which houseplants they choose to feast on, and cyclamen are, unfortunately, not immune to the little sap suckers. These are small, oval-shaped insects covered in a white, wax-like coating. Typically, mealybugs are found on the bottom of leaves and along the stems of plants.
Although easier to see than aphids, symptoms of mealybug infestations are similar to those of their aphid counterparts. The insects puncture plant tissues with their needle-like mouthparts and suck out the contents of plant cells.
Once digested, the insect deposits its excrement in the form of a sugary liquid called honeydew. Leaves that are directly beneath feeding mealybugs appear wet but, when touched, are very sticky due to this waste matter.
Because mealybugs are sucking out the plant’s cell contents, cell pigments are also being consumed. Thus, leaves that have mealybugs will become yellow.
The excrement covering the leaf surface will also decrease the amount of sunlight the leaf can absorb, resulting in premature yellowing.
Mealybugs can be controlled with a variety of methods. You can dislodge the insect from the plant with a soft toothbrush or cotton swab.
Another method is to dab a clean cotton swab in 70% rubbing alcohol and gently swab the insect directly. The rubbing alcohol dries out the mealybugs’ bodies and eventually kills the insect through dehydration.
Commercially available pesticides like insecticidal soaps and horticultural oils work well in controlling mealybug populations. Read the label for correct dosing and application intervals.
Some thrips are pest insects, while others work as decomposers of plant debris or predators of pest insects. Since we are talking about cyclamen, we are going to focus on the harmful group of thrips that feed on leaves.
Thrips are a common pest among cyclamen. Their bodies are small, oval-shaped, and often compared to a single grain of rice in size.
They come in various colors, from brownish-black to yellowish-orange. Typically, thrips hang out in younger leaf tissue and flower buds because these areas are small and tight, keeping the thrips out of the light.
The problem with thrips is that they are often a vector of plant disease. Many times viruses show themselves in plants as dark green/black colored leaves that are twisted and contorted. You can also find streaks of white within flowers or yellow/orange lesions on leaves. Prevention of thrips is one of the best ways to prevent the introduction of viruses and fungi to your houseplants.
Thrips insert their mouthpart into the cells of the leaf tissues. Instead of feasting on the sap of the plant, they insert their saliva in the tissues, then suck out the entire cell contents.
Because the cell’s contents are gone, the cell itself becomes an empty pocket with no coloration remaining in the leaf. The pockets eventually dry out, resulting in areas of tan-to-white patches on the leaves.
Thrips will also eat the pollen of cyclamen flowers. When the thrips infestation occurs in the flowers, the flowers often fail to open or show damage upon opening, including:
- Colorless tissue
- White-colored spots/streaks on the flower petals
- Distortion of the flower as a whole
If you think you have thrips, testing for it is easy:
- Take a plain white sheet of paper.
- Place under the flower or leaf you think is infested.
- Gently tap the flower or leaf on the white paper.
- If thrips are present, they will fall out of their protective hiding spots and onto the white paper.
Thrips can be difficult to control once established. One reason is that they are so good at hiding. it can be extremely difficult to spray them with chemical pesticides. The chemicals cannot make contact with the thrips, so the thrips are not killed and can become resistant to pesticides if exposed to them often.
Systemic pesticides are more effective against thrips because they must ingest the chemical to be exposed. Be sure to read the pesticide label prior to use to be sure the product is labeled for use on thrips in cyclamen. The label will also tell you what personal protective requirement you will need to wear while applying the chemical as well as how often to apply it.
In nursery greenhouses, there are a limited number of chemicals labeled for use to control thrips. Because of the limited pesticides available, we often use biological control to keep our thrips population to a minimum.
Biological controls would include the use of natural thrips predators or even bacteria and fungi that are harmful to the thrips but not to us. These predators can fit into the tight spaces loved by thrips and help control the populations much better than chemical applications can.
If the thrips population is too bad, and you can’t seem to get a handle on it, you may want to discard the plant to remove the pest insect from your home and prevent them from infecting any other plants you may have.
Frequently Asked Questions
What Kind of Light Do Cyclamen Need?
Cyclamen do not like direct light. However, the definition of direct light varies depending on the time of year it is. They need 4-6 hours of indirect, bright light. Indirect light means the light has to travel through something, like blinds, curtains, leaves from outdoor trees, and does not cast a clean shadow.
Eastern or western exposures giving 4-6 hours of sun work great. 4-5 hours of filtered southern exposure may also suffice. Watch for signs of too much light, which could include leaf curling, or leggy growth. Slowly adjust accordingly.
Will my Cyclamen Bloom Again After Dormancy?
Maybe. Typically, the light levels in an average household are not intense enough to induce flowering of your cyclamen for a second time. But, that doesn’t mean it’s impossible. As the crown begins showing new growth out of dormancy, move your cyclamen to a brightly lit location (it should be September-ish, so bright September sun is nowhere near as intense as bright July sun).
Increase the watering frequency and add a monthly feeding regime of a liquid houseplant fertilizer that’s higher in phosphorus to your cyclamen maintenance. For example, you may see a fertilizer bearing 4-12-4, or any number combination, but you want the middle number (phosphorus) to be the highest. If your cyclamen is going to re-bloom, it will most likely be around mid-winter.
What Type of Fertilizer Do Cyclamen Require?
Cyclamen are not particularly finicky about fertilizer. You will want to feed your cyclamen with a houseplant fertilizer that is higher in phosphorus, if you want to promote flower production and blooming. The label will provide you with the correct fertilizer to water ratio and how often to apply the fertilizer, in order to prevent tissue burn to the plant.
Just remember, avoid fertilizing as the plant goes into dormancy. Fertilizing too late in the growing cycle will prevent the cyclamen from going into its rest period, and may be detrimental to the plant’s overall health.
Yellowing of cyclamen leaves is a sure symptom of distress within the plant itself. Some of those reasons we can easily control, like over or under-watering, and others happen by no fault of our own; they’re called pests for a reason. Now that you know the basic life cycle of cyclamen, you can troubleshoot any yellowing foliage much easier and resolve issues much quicker.