Dumb Canes are tough houseplants, and they’ll often hang on for a long time even in less-than-ideal growing conditions. That can make it even more alarming when they do start showing signs of a serious problem, such as rapid wilting and loss of leaves. So what do you do if your Dieffenbachia is dying?
The first step is to make your Dumb Cane is as comfortable as possible, eliminating environmental stress. Make sure the temperature is stable and the plant is away from direct sun. Then inspect the leaves, potting mix, and roots for signs of serious issues like pest infestation or root rot. These problems require aggressive treatment, but may still be fixable.
Your plant will need lots of TLC after its ordeal, especially if you have to uproot and replant it. Keep the humidity above 70% if at all possible for the next few weeks, and be vigilant about avoiding overwatering and sunburn. Keep reading for a detailed, step-by-step guide on how to save a dying Dumb Cane.
Step 1: Move Your Dumb Cane to a Stable Environment
A sudden decline in your Dieffenbachia’s health may be due to a poor choice of location. One common issue is harsh lighting. If your plant sits in a southern or western window, it could be at risk of sun scorch. A bad sunburn can cause the foliage to wither and die at an alarming speed.
Drafty windows are another problem. Even brief exposure to low temperatures can result in cold shock, producing wilting and loss of leaves. Excessive heat – above 90 degrees or so – will have similar effects. Air conditioners, heating vents, and fireplaces can also cause temperature shock if your Dieffenbachia sits too close to them.
Move your plant into a spot where it will receive only indirect light and the temperature stays between 60 and 85 degrees. Your Dumb Cane should recover after a couple of weeks in a more stable environment if its health problems were caused by heat, cold, or sun. If not, keeping the plant away from potential stressors will help it stay alive while you address the real issue.
Step 2: Prune Dead Foliage
Even when a leaf is almost completely withered, your Dieffenbachia may be spending some energy trying to keep it going. Do your plant a favor and trim off any foliage that’s turned fully brown and crispy so that your plant can devote those resources to its recovery.
If there are leaves with browning edges or tips that still have some healthy green tissue, leave them on the plant, though you can snip away the dead parts.
We recommend using a set of pruning scissors for the sake of precision, but the scissors from your kitchen’s junk drawer are probably fine too – as long as they’re sharp. Sanitize the blades with rubbing alcohol or a 10% dilution of some household bleach. That way, you won’t accidentally introduce an infection into the cuts you’re making.
If you’re certain that sunlight or temperature stress caused your Dumb Cane’s issues, your work is done. Otherwise, move on to Step 3.
Step 3: Inspect the Foliage for Pests
As you prune the dead leaves away, look over your Dumb Cane’s foliage for signs of pests. Rapid wilting and withering are often due to bugs feasting on your plant’s juices.
Here’s what you should look for:
- Insects. Some pests are large enough to see without a magnifying glass. Dull brown bumps on the trunk could be scale insects, bits of white fuzz might be mealybugs, and colorful bubbles on the younger stems are probably aphids.
- Clear, sticky liquid. All three of the bugs we just mentioned will deposit a sugary sludge called honeydew on your Dumb Cane’s leaves.
- Sooty mold. This fungus grows in honeydew, creating black or gray patches that look like charcoal smudges.
- Cobwebs. Spider mites like to fill the gaps between leaves and stems with a thin, dusty-looking webbing.
- Leaf damage. Pests often leave scars on the foliage. Spider mites, aphids, and thrips produce tiny, silvery specks that make the leaves look faded and dusty. Scale and mealybugs create small round blotches of white or brown tissue.
If you discover a pest issue, you can pretty much ignore the rest of this list, because dealing with bugs requires a unique type of treatment. If you didn’t find any signs of pest activity, skip to Step 4.
For detailed instructions on Dumb Cane pest control, take a look at our article on the topic. But here’s a brief breakdown:
- Quarantine. Isolate your Dieffenbachia from any other houseplants.
- Rinse. Spray your Dumb Cane down with a strong stream of water to knock off as many bugs as you can.
- Swab. Mix up 4 parts water and 1 part 70% isopropyl alcohol, apply it to a cotton makeup pad or a Q-tip, and wipe down every bit of your plant that you can reach.
- Spray. Create a neem oil solution – 1 teaspoon of neem for every liter of water. Mix about ⅓ teaspoon of mild soap into the water first to let the oil dissolve. Then spray your Dieffenbachia thoroughly with this blend.
- Repeat. Let your plant dry off, wait a few days, and repeat steps 2-4. You’ll have to do this every few days until you’ve eliminated any bugs. It may be helpful to alternate between neem oil and other insecticides like hydrogen peroxide.
Step 4: Check the Soil
At this point, you’ve ruled out most of the factors that could harm your Dieffenbachia’s leaves directly. That means it’s time to assess the conditions in the soil.
Start by checking whether it’s wet or dry. A glance at the surface isn’t enough – the soil down by the roots could still be very damp even if the top looks dry. Poke an unglazed wooden chopstick or barbecue skewer down to the base of the pot, leave it there for a minute, then pull it back up. (A soil moisture meter should also work well.) If the deeper parts of the planter are bone dry, you have an underwatering issue.
On the other hand, if the soil is wet and sludgy on top or deeper down, your Dumb Cane may be suffering from overwatering. If you water your Dumb Cane too often or the potting mix stays damp for too long, it smothers the roots and may cause them to rot.
Possible indicators of overwatering and root rot include:
- Nasty smells wafting up from the soil
- Visible mold or fungus
- Soft, mushy stems on your Dieffenbachia
- Lots of fungus gnats living in the pot
Step 5: Flush the Soil
You should only be at this step if you’re sure that your plant isn’t dealing with sunburn, temperature stress, pest damage, or overwatering. There are two possibilities to consider next.
The first is severe underwatering. Dumb Canes handle drought better than swampy soil, but if you neglect yours for long enough, it will shrivel up and die. Soil that’s packed into a solid, crusty disk is a pretty good indicator that your plant is dying of thirst.
The second possibility is fertilizer burn. When mineral salts from tap water or plant fertilizer build up to high enough concentrations in the soil, they can leach water away from a Dieffenbachia’s roots.
As it happens, both of these conditions can usually be fixed by a healthy dose of water. Put your Dumb Cane in the sink and pour filtered or distilled water into the soil. Go slowly and steadily, letting the moisture soak into the soil and then run outfrom the drainage hole in the bottom of the pot. Use 4-5 times the total volume of your Dieffenbachia’s container.
This should refresh a thirsty Dumb Cane and wash excess minerals out of the soil. After a day or two, you should notice signs of improvement as your plant straightens up and stops drooping.
If your Dieffenbachia still seems to be hurting, continue to step 6.
Step 6: Inspect and Prune the Roots
At this point, you’ll need to look directly at the root mass to pinpoint the problem. Grip your Dumb Cane firmly by the base of the trunk and tip it out of its pot. Clean the roots off with your fingers, rinsing with warm water if necessary.
You may notice that they’re packed into a tight knot in the shape of the container. This means your plant is root bound, which could be the source of your Dieffenbachia’s troubles – a severely root bound plant can’t take in enough water and nutrients to keep its foliage healthy. Work the roots apart with your fingers, going slowly and gently to avoid tearing them.
If the roots are seriously knotted, you may want to prune the longer ones back a bit. This will give the plant more room to grow when you repot it.
Next, look for root rot. Infected roots will be black or gray instead of white, and they’ll feel slippery or squishy. Snip off any roots that show even a hint of rot, disinfecting your scissors between cuts as we described in Step 2. Dunk the roots in a mix of 1 part hydrogen peroxide and 2 parts water to kill any microbes you missed.
If you’ve taken off more than ⅓ of the root mass, trim away the same percentage of the leaves. This will help your Dieffenbachia conserve energy as it heals.
To read more about root rot in Dieffenbachias and what to do about it, check out: How to Save an Overwatered Dieffenbachia from Root Rot.
Step 7: Repot Your Dumb Cane
Now that you’ve cleaned up your Dieffenbachia’s root system, you need to get it back in the ground. We’d recommend taking this opportunity to place it in fresh potting mix. Dumb Canes do best in soil that can hold a bit of moisture but lets excess water drain away quickly.
If you’re going to buy potting mix off the shelf, use a blend formulated for African Violets. DIY-inclined houseplant owners should get good results with 40% coarse perlite, 25% coconut coir, 25% orchid bark, and 10% vermicompost. (Read more about the best soil for Dumb Canes here.)
If your Dumb Cane was root bound, move it into a container that’s around 2 inches wider than its old one. Make sure that the pot you select has drainage holes in the bottom, or you’ll be negating the benefits of your chunky soil blend.
If your plant showed any signs of root rot, throw away all of the potting soil and use new, even removing as much from the root system as possible. Also, completely sanitize your container with a bleach mixture if you intend to use the same one. Once you’ve dealt with the infection you won’t want to risk reintroducing fungi through the old potting soil or pot.
Step 8: Keep Your Plant Cozy
If you’ve followed the steps above, your Dieffenbachia should no longer be actively dying. However, it will be in a vulnerable state until its roots heal. You can ease its road to recovery by making its environment comfortable.
Your first priority should be to avoid adding any stressors:
- Don’t apply any fast-acting fertilizer for at least a month.
- Don’t water your Dumb Cane unless the top two inches of soil are dry.
- Don’t let it sit in direct sunlight.
It’s also helpful to keep the humidity high. A humidifier is usually your best bet, though you can also create a one-plant greenhouse by placing a clear plastic bag over the foliage.
Once you see new leaves emerging, your Dumb Cane is through the worst of its troubles.
The Long Shot
Sometimes, despite your best efforts, your Dieffenbachia will continue to waste away. If it’s been damaged too severely by cold shock, root rot, or some other problem, even the steps above won’t be able to save it.
In this situation, you do have one option left: you can kill your Dumb Cane and bring it back to life.
Dieffenbachias can grow back from stem cuttings, so if there’s a portion of the trunk that’s still healthy – even a small one – you can slice it off and plant it in a pot of its own. Now that it’s free of the damaged roots, it should be able to sprout into a new, healthy plant. See our article on propagating Dumb Canes from cuttings for more information.
Give your cutting the same treatment we recommended in Step 8. It may take a while to grow to the same heights as its parent, but eventually, you should have a healthy, thriving Dumb Cane again.
Seeing your Dumb Cane approaching the brink of death is scary, but with the treatment plan we’ve just described, you’ve got good odds of saving it. And the lessons you learn in the process should help you keep it healthy in the future. We hope your Dieffenbachia survives and goes on to lead a long, happy life.