A poinsettia bought from the grocery store in early December, still in its gold foil sleeve, usually looks fine on the way home — and then drops its leaves. The cause is often a short stop somewhere cold: even a quick errand with the plant sitting in a freezing car can be enough. It looks fine when it gets home, but the next morning there are green leaves on the windowsill, and by midweek the bottom third of the stems are bare. The natural reaction is to blame the store, then the water, then the radiator, and to water it more because it looks thirsty. Water pools in the bottom of the foil sleeve, and by New Year’s it is a few red bracts on sticks.
What actually happened was two separate mistakes stacked on top of each other: a cold shock in the car and wet roots inside the sleeve. Poinsettias (Euphorbia pulcherrima) are subtropical shrubs from Mexico that get sold in the coldest, darkest month of the year, so leaf drop is easily the most common complaint about them. The good news is that most of the causes are easy to read once you know what each one looks like.
Quick triage
Did the leaves drop within a few days of bringing the plant home, especially in cold weather? Start with cold exposure and transplant shock. Poinsettias react to chilling fast, and the damage shows up a day or two later.
Is the plant still in a foil or plastic sleeve, and is the soil wet several days after watering? Go to the overwatering section. Lower leaves usually yellow before they fall in this case.
Are the leaves wilting and dropping while the soil is bone dry and the pot feels light? That is underwatering. Poinsettias in small grower pots dry out much faster than people expect.
Is it sitting next to a door, a drafty window, a heat vent, or a fireplace? Read the section on drafts and heat.
Is it February or later, and the colored bracts are fading and falling along with some leaves? That may just be the end of the bloom cycle. Read the last section before you throw anything out.
Cold exposure and the trip home
Poinsettias start to suffer below about 50°F, and a few minutes below freezing can be enough to cause chilling injury. The frustrating part is that the plant often looks fine for a day. Then the leaves either drop green or turn dull and droopy before they fall. A cold windowpane can do the same thing, since the glass in December is often much colder than the room, and a leaf pressed against it gets a small dose of frost every night.
This is why garden centers wrap poinsettias in paper or plastic sleeves at the register. If you are buying one in cold weather, make it the last stop, ask for a sleeve, and do not leave it in a parked car. If the damage is already done, there is not much to fix. Move the plant away from the glass, keep it in the 60 to 70°F range, and leave it alone. Leaves that are already damaged will fall, but the stems usually push new growth later as long as the roots stay healthy.
Overwatering and the foil sleeve
This is the one that kills most holiday poinsettias, and the decorative foil is usually involved. The sleeve looks nice, but it has no drainage, so every time you water, the excess runs out of the grower pot and sits in a puddle that the roots stay in. Within a week or two the lower leaves turn yellow, the whole plant droops even though the soil is wet, and leaves start falling from the bottom up.
Take the plant out of the sleeve to water it, let it drain in the sink, and put it back only once it has stopped dripping. Or poke a few holes in the bottom of the foil and set it on a saucer. Water when the top of the soil feels dry to your fingertip, not on a fixed schedule. If the plant is collapsing and the soil smells sour, slide it out of the pot and check the roots: healthy ones are white or tan, rotten ones are brown and mushy. Our guide to root rot in houseplants walks through what to do next, and if you are not sure which direction you are wrong in, overwatered or underwatered lays out the differences side by side.
Underwatering in a tiny pot
The opposite problem is just as common. Holiday poinsettias are grown in light, peat-heavy mix in pots that are small for the size of the plant, and the soil can go from damp to dry in two days in a heated room. When that happens the leaves wilt, and a poinsettia that wilts hard even once tends to drop a batch of leaves a few days later, even after you water it and it perks up.
Lift the pot after watering so you know what “full” feels like, then lift it again every day or two. When it feels noticeably lighter and the top of the soil is dry, water thoroughly until it runs out the bottom. If the mix has shrunk away from the sides of the pot, water slowly or set the pot in a bowl of water for ten minutes so it rewets evenly. The general signs of thirst versus root trouble are covered in why is my plant drooping.
Drafts, heat vents, and fruit bowls
Poinsettias like steady conditions. A spot by the front door gets a blast of cold air every time someone comes in, a heat register dries the leaves and soil out in hours, and a mantel above a working fireplace does both. Any of these will cause a steady drip of yellowing or dropping leaves. Ideal is somewhere with bright light, temperatures between about 60 and 70°F during the day, and no air moving directly across the plant.
One less obvious cause: poinsettias are sensitive to ethylene, the gas ripening fruit gives off. A plant parked right next to a bowl of bananas or apples on the kitchen counter can drop leaves and bracts faster than it would elsewhere. It is not usually the main problem, but if everything else checks out, it is worth moving the fruit.
Low light and the end of the season
A poinsettia in a dim room will slowly shed its lower green leaves to match the light it has, and the bracts lose their intensity. Give it the brightest indirect light you have, ideally a few feet from an east or west window, or a south window with a sheer curtain. A grow light is a reasonable backup if your winter windows are poor; see our grow light picks.
It also helps to know what the plant is doing. The red “petals” are bracts, which are modified leaves. The actual flowers are the small yellow-green buds in the center, called cyathia. Once those flowers finish and drop, usually sometime from late winter into spring, the bracts fade and fall soon after, and the plant often loses some older green leaves as well. That is a normal end of the bloom cycle, not a sign that you did something wrong. At that point you can either compost the plant or keep it and try to get it to color up again next year.
A few things people ask
Will the leaves grow back?
Leaves that have fallen will not reattach, but as long as the stems are still firm and the roots are healthy, new leaves will come from the nodes, usually in spring once the days get longer. A plant that lost most of its leaves to a cold car ride can still turn into a decent green shrub by summer.
Why are the leaves curling and dropping but still green?
Green leaves falling off suddenly usually point to a shock: cold, a hard wilt, or a big change in location. Yellow leaves falling over a week or two point more toward wet roots or low light.
Are fallen poinsettia leaves dangerous to my cat or dog?
Their reputation is worse than the reality. The ASPCA lists poinsettia as toxic to dogs and cats because the milky sap irritates the mouth and stomach and can cause vomiting, but it also notes the toxicity is generally overrated. Still worth sweeping up dropped leaves if you have a pet who chews things.
Should I cut off the bare stems?
Not in winter. Leave them until spring, when you can cut the whole plant back to about four to six inches as part of regular care. Cutting now just removes the nodes that would have leafed out.
Once the leaf drop has stopped and the plant is settled, the rest is everyday care. Our complete poinsettia care guide covers light, watering, cutting it back in spring, and the nightly darkness routine that gets the bracts to turn red again next winter. Next reads: Why Is My Oxalis Drooping?, Why Is My Kalanchoe Drooping or Losing Its Leaves? and Why Is My Cyclamen Turning Yellow?.