Though not the hardiest plants, poinsettias will do reasonably well for weeks, if not months, when you care for them properly.
But seeing leaves fall off your otherwise merry poinsettia can send your heart pounding like a jackhammer.
Why is this happening, and is there anything you can do to save your Christmas Star from an untimely demise?
Poinsettias characteristically drop leaves in response to physiological stress. Most often, that’s due to exposure to sudden temperature changes, cold drafts, or an arid environment. The plant will also shed leaves (sometimes bracts) because of extreme thirst, overwatering, disease, and pest infestation.
Knowing what’s upsetting and causing your poinsettia’s leaves to fall off is half the story.
I’ll show you common problems that may be troubling your plant and how to address each one.
How Long Do Poinsettias Last?
The lifespan of poinsettias is often a subject of debate. Part of the reason is that these beautiful tropical plants have become almost synonymous with Christmas.
They’re typically considered among the best-selling holiday houseplants in the US and worldwide.
It’s not hard to understand why poinsettias are so popular, though. The most obvious appeal is their beautiful bracts. They’re a colorful bloom of modified foliage often misconstrued as flowers.
Moreover, poinsettias can come in various gift-worthy sizes and stunning hues. You have probably seen them in their breathtaking pinks, glorious reds, or whites.
Little wonder poinsettias are associated with the festive season, which may also be why most people think they’re short-lived.
Most poinsettias bought during the winter holiday will last roughly four to six weeks before they begin to shed their leaves.
This is usually a natural way of your plant entering dormancy. Most people dispose of poinsettia at this point, thinking it’s a goner.
Bracts are usually the last to fall off. Contrary to common belief, poinsettias can last longer than a few weeks or months.
With proper care, they can last many months. Wouldn’t you believe it? You can revive, re-grow, and re-bloom your poinsettias for years with sufficient care.
Causes of Poinsettia Leaves Dropping
 You Have Let the Soil Become Too Dry
If your poinsettia is extremely underwatered, it will likely shed foliage and start wilting. The flower bracts and leaves are the first victims. They will go slightly limp and wilt before dropping off.
If the soil feels bone-dry to the touch, this should become pretty obvious that your poinsettia is extremely thirsty.
If there’s something I’ve learned, the hard way is to check if the soil is evenly moist and your poinsettia is healthy before you bring it home from the store or nursery.
Now, you should give your wilted poinsettia a good soak immediately. Make sure to irrigate thoroughly and deep enough such that excess liquid comes out of the drainage holes.
Let your plant sit on the excess run-off on the saucer for fifteen to twenty minutes, then dump it out.
Your poinsettia’s leaves should recover their turgidity upon deep irrigation.
Unfortunately, if the stress has already taken its toll on any leaves, they will turn yellow and fall off after a few days.
You’re not at fault, and there’s little you can do to save the affected foliage at that point.
Wouldn’t you know it! Your poinsettia will respond in the same manner when it’s given too much water as when the soil is allowed to become too dry.
That’s true; your overwatered poinsettia’s leaves will also start wilting and fall off.
The reason behind the leaf shedding is common but nefarious. If you let your poinsettia stand on “wet feet,” the roots will drown and begin to rot. Roots need oxygen to breathe, just like you and I.
Consequently, the leaves will turn yellow, wilt, and drop despite abundant moisture in the roots. Other symptoms of an overwatered poinsettia include browned, pale, or discolored foliage.
You may also spot some tiny white blisters on the leaves due to edema, making it an early warning.
If the soil is wet or soggy yet your poinsettia is wilting, then that’s a surefire clue that you have overwatered it. Also, check your plant for root rot – signified by dark or rusty brown, mushy roots.
In a severe case, such as when heavy root rot has set in, you may not be able to revive your poinsettia. You’d be better off replacing it with another poinsettia.
Thankfully, your mildly overwatered poinsettia can recover.
- But you need to take some drastic steps, first to stop irrigating your plant immediately.
- Next up, make sure the container has enough drainage holes. If you recently bought or received your poinsettia, remove the wrapping sleeve. It may prevent excess water from draining.
- Take your plant out of the pot and allow the soil to dry by placing it on a magazine.
- If there’s any sign of root rot, you should wash the roots. Remove all of the soil and trim away any affected roots.
- Treating the remnant healthy roots using copper or sulfur-based fungicide will help prevent further spread. Add hydrogen peroxide to the soil mix before repotting your plant.
- For best results, use a new terracotta pot and a fresh lot of peat-based potting mix.
How Often Should You Water A Poinsettia?
As a veteran owner of houseplants, I’ve one trick up the sleeves that helps keep my poinsettia well-watered.
You must not stick to a calendar watering schedule. Instead, let your poinsettia tell you when it needs a drink.
This is where our trusty finger moisture test comes into play. Insert your index finger into the soil after every three to four days.
You should water only when the top few inches (up to around the second joint of your finger) is dry if the soil is still moist, check back after a couple of days.
Talking of watering, you should irrigate your poinsettias until excess liquid runs off into the saucer. Let the soil soak up water for 15-20 minutes, then dump the excess.
 Sudden Temperature Changes and Extreme Cold
It might seem illogical for a houseplant that blooms elegantly in the long dark nights of winter, but cold is poinsettia’s enemy #1.
Even a five-minute exposure to cold drafts, frost, or a low temperature below 50°F (10°C) can do a number on your plant.
The same is true of being subjected to hot drafts, direct sunlight, and sudden temperature changes.
Your poinsettia won’t be happy at all and will become distressed. As a result, it will display its displeasure by losing both bracts and leaves.
The lower and older leaves will be the first to go. If the temperature stress is prolonged, the leaf drop will advance upwards.
You will be surprised to find your poinsettia almost naked with only a few sets of foliage and colored bracts on top.
Prevent exposure to cold temp right from the get-go. Tell the vendor to carefully wrap your poinsettia with insulation to protect it from biting cold when bringing it home.
Proper care at your house will help prevent leaf drops. First, keep your poinsettia at warmer day temperatures of up to 75°F (24°C). They prefer slightly cooler temperatures in the ideal range of 60-65°F (15-18°C) at night.
Moreover, you must keep your poinsettia away from windy or drafty doors, windows, and cooling vents. Park it in a warm area that sees only bright, indirect sunlight.
You can place it near heating elements like radiators but keep away from direct sunlight, drafty heating vents, or fireplaces.
An unhealthy or diseased poinsettia is an unhappy plant that’ll show distress by shedding leaves.
You should scout it regularly for a range of stem, root, and crown rots caused by pathogens like Thielaviopsis, Pythium, or Rhizoctonia.
This systemic bacterial wilt will blight the crowns, bracts, and leaves. It manifests first as brown cankers or long, water-soaked streaks on foliage.
Brown necrotic spots may appear on the leaves before they fall off. Look out for long cracks along the stems as well.
Remove affected plant material immediately and increase aeration. Avoid overhead irrigation and maintain temp consistently above 60°F (15°C).
There is no effective chemical treatment for this. You need to get rid of the plant or plant parts and bury them under the soil.
Do not mix them with your compost as there will be possibilities of spreading infection.
Caused by fungus Spot anthracnose, poinsettia scab is symptomized by abnormally elongated nodes and many long, raised small lesions on the stems.
These stem cankers are pale buff and encircled by a reddish or purple halo. Also, visibly large brown spots appear on the upper side of the leaves. This causes the leaves to curve inwards, wilt, and eventually fall off.
Isolate any diseased poinsettia and trim away affected parts. Spray your plant using a copper- or sulfur-based fungicide on a 7-day to 10-day interval until the pathogens are gone. (Source: Florida Department of Agriculture)
Bacterial Blight and Cutting Rot
Botrytis blight is the most common bacterial blight that affects poinsettias. It also causes stem canker, as well as cutting rots.
The disease is most aggressive in hot, humid conditions. Cutting and leaves usually develop water-soaked spots, ultimately falling off.
Maintain a high level of sanitation when handling your poinsettia. Avoid overhead watering or splashing water on the foliage.
Create a well-aerated environment. You need to sterilize the potting mix before use. Prevention is the only way of treating bacterial diseases.
Pythium Root Rot
Poinsettias affected by Pythium usually bloom and shed leaves prematurely. The infection is fueled by dampness and over-fertilizing.
For prevention, use fungicide drenches to kill fungus gnats, avoid overwatering, and don’t over-fertilize. Control pests like whiteflies as soon as they appear. Use a Pythium-specific fungicide to control.
Rhizoctonia Root and Crown Rot
This fungal disease is normally spread by splashing water. Infections on the leaves are particularly aggressive with dry brown canker on cuttings.
Tan lesions with browned or dark margins appear on stems and cause your plant to collapse.
Avoid overfertilizing or planting your poinsettia too deep when repotting. Remove infected crowns and roots immediately. Dip the remaining root strip in fungicide before repotting.
Thielaviopsis Root Rot
Also known as black root rot, the Thielaviopsis root rot is as ominous to your poinsettia as it sounds.
Older leaves usually turn yellowish-green, as younger ones are stunted and take a red tinge. They’ll wilt and fall off over time.
Proper sanitation is the best preventive measure here. Avoid high soil PH and exposure your plant to low temp.
For treatment, seek out biological Trichoderma on amazon. Fungicides like benzimidazole have also shown promise against Thielaviopsis.
 Does Your Poinsettia Have a Pest Infestation?
If your poinsettia is defoliating, you shouldn’t rule out pest infestation. Whiteflies particularly love lounging and suckling on your precious poinsettia.
They drill holes into the foliage and draw out the gummy sap.
Unfortunately, these sap-sucking bugs cause leaf damage. The leaves will gradually become yellowed and then fall off.
Other common insects found on poinsettias may include mealybugs, spider mites, shore flies, thrips, and scale. They all produce the same results as whiteflies.
The fungus gnat, which usually lives in the potting matter, can be devastating. They cause rot to stems, foliage, roots, and crown. If they result in Pythium root rot, the leaves will drop off prematurely and bracts will bloom too early.
The preventive action is to inspect your poinsettia for insect infestation before you purchase or bring it from the store.
These pests are particularly invasive in neglected nurseries and greenhouses. Make sure to isolate your insect-infested plant from the rest of the houseplants.
You can use a variety of treatments and control measures. These include rubbing alcohol, manual squishing, horticultural oil, neem oil, and insecticidal soap spray.
You can also wash off the insects, but spray at a ten-day interval.
 Insufficient Light
Poinsettias love basking in bright filtered or indirect natural sunlight. While exposing your poinsettia to direct sunlight is a no-no, too little light can cause the leaves to turn yellow and drop.
Sadly, this may go unnoticed for a long, as poinsettias take up to two months to respond negatively to low light.
Place your poinsettia in a bright, south-facing spot sheltered from direct sunlight using a light curtain or drapery. Your plant can also tolerate a few hours of sun, though.
 Being Left Boxed or Wrapped for Too Long
There’s a good chance that you got your poinsettia as a Christmas present. Perhaps you saw its beautiful bracts and decided to bring it home to brighten up the space for the holidays.
However, if you don’t remove the gift-wrapping or unbox your plant as soon as it arrives, the leaves will drop.
Believe it or not, this tropical plant produces ethylene, which is a toxic yet sweet-smelling and invisible gas.
Usually, this gas diffuses immediately into the thin area and has no consequence.
However, if you keep your poinsettia enwrapped, the toxic gas will saturate inside the wrapping or box.
Eventually, the concentration will be high enough to affect the plant, causing bracts and leaves to drop off.
Remove the wrapping sleeve or box immediately when your poinsettia gets home. Make sure there’s generous aeration around your plant.
 Low Humidity
Poinsettias are tropical natives that enjoy humid environments. While they can tolerate relatively dry air, extremely low humidity (anything below 30%) will cause leaves to curl up and begin to fall off.
The leaves may also turn brown on the edges and tips.
If the soil dries out faster than usual, the air around your plant may be too dry.
Consider misting, using a humidity water tray, or setting up a humidifier to increase humidity. Bringing your houseplants closer together may also do the trick.
 Too Much Fertilizer
Applying the wrong fertilizer can cause leaves to drop. Or using too much of it will result in a similar outcome.
This is especially true if the soil has a build-up of salts and too high levels of boron or ammonium. The same effect may show up when you use softened or chlorinated water.
Feed your poinsettia a well-balanced water-soluble houseplant fertilizer around early spring (in most US zones).
Continue doing so monthly throughout the summer month. Cut the fertilizer strength by half or more if leaves are dropping.
Will My Poinsettia Leaves Grow Back?
It depends – if your poinsettia is severely diseased, then no. Otherwise, it’s possible to regrow the leaves.
Even if all leaves have been stripped down, your poinsettia can still produce foliage once the dormancy period is over. However, you must take great care of your plant to encourage leaves to grow back:
- Stop watering once the foliage has been shed. Then, place your plant in a cool spot with indirect light. Keep the temperature at around 50-55°F (10-13°C) until early spring.
- Once new growth emerges in spring, trim your poinsettia to three-eight inches above the soil level.
- Consider repotting your plant in a container 1-2 inches more significant than the previous one. Use a soil mixture with 1 part perlite, two parts compost, and three parts potting mix.
- Place your plant in bright light. Make sure to stop watering until the top inch of the soil feels dry.
- Fertilize using water-soluble houseplant fertilizers every 7-10 days using recommended strength
- For a bushy poinsettia, pinch back new shoots at the tips, leaving two to three nodes on every new shoot. In every cluster of leaves, pinch out the middle leaves to keep only three to five.