Root rot is the most common problem I’ve encountered with my dieffenbachias. Even worse, it’s most likely to kill your dumb cane if you don’t take prompt action.
If you get a foul smell from the soil, your Dieffenbachia likely has root rot.
It’ll spread to leaves, causing them to turn yellow and develop brown spots. With careful inspection, you’ll be able to identify the cause and save your Dieffenbachia.
Dieffenbachia root rot is frequently caused by an excess of water. Overwatering or planting your Dieffenbachia in soil with poor drainage are two common causes.
Before repotting your plant, remove any brown, squishy roots and replace them with new potting material. If you cannot save the Dieffenbachia, propagate it from cane cuttings.
Contents
Signs of Dieffenbachia Root Rot
Your Dieffenbachia will be devastated if it suffers from root rot. In addition to causing irreparable harm to the plant’s vital root system, it has the potential to spread throughout the entire plant.
Even though the dieffenbachia root rot is hidden beneath the soil, you can still see the usual signs on the leaves, stems, or soil, fortunately.
Root rot can be spotted by the following symptoms:
Overgrowth of Soil Mold
Root rot is often caused when the soil is too wet. Possibly, the potting material is holding too much water.
Or, more commonly, you’re watering your plant too frequently. A pot without drainage holes will cause the soil to become wet or soggy.
Soil fungus will eventually germinate and grow due to excessive water, for whatever reason. As a result, you’ll notice a buildup of mold or mildew on the soil.
Leaf Yellowing
Yellowing leaves are frequently one of the first signs of dieffenbachia root rot. Because of root damage, nutrients (such as nitrogen) required to maintain leaf greenery are no longer reaching the leaves.
Yellowing leaves are typically wilted, sulky, or limp. They will eventually turn brown or black and fall off the plant.
Stunted or Distorted Growth
Root rot reduces your Dieffenbachia’s ability to absorb nutrients and water.
Because of this deficiency, the leaves will be much smaller than usual, twisted, or otherwise distorted. They may even stop growing entirely.
In addition, new leaves and shoots will appear later than expected. Finally, in severe cases of root rot, your Dieffenbachia may not produce any new growth at all.
Wilting that is Persistent and Severe
Dieffenbachia root rot can cause your plant to appear droopy and limp no matter how much water you give it.
This is due to the damaged roots’ inability to absorb moisture from the soil. As a result, your Dieffenbachia will perish in a sea of abundance.
Leaf Drips or Guttation
Overwatering causes guttation, which is a physiological response. Since overwatering can cause root rot, it’s a clear indicator that it’s about to happen.
Dieffenbachias are drought-tolerant plants that will not tolerate standing in water. Instead, they will attempt to compensate by excreting excess water through the leaf edges.
Foul-Smelling, Brown, Mushy Roots
Checking the roots’ color is the most effective litmus test for root rot. When touched, affected roots appear black or reddish-brown and feel spongy or mushy.
Other root-related symptoms include:
- They may also stink with a foul, decaying odor.
- Rotten roots are usually limp.
- Their outer layers are slimy and can peel off when pulled, leaving only the inner layer.
Brown Spots on Leaves
The bad news is that brown spots on the leaves caused by water indicate root rot.
The good news is that they are an early warning, so you still have time to act and save your dumb cane. First, however, keep an eye out for wet, browning leaf tips and margins.
What Causes Dieffenbachia Root Rot?
Excessive dampness in the soil is a significant contributor to the development of root rot. It impairs soil aeration, damages roots, and promotes root rot disease.
In some cases, the fungal rot disease can begin on the foliage or stems and spread to the roots.
In any case, here are some possible contributors or causes of dieffenbachia root rot.
[1] Overwatering Damages Dieffenbachia’s Roots
Excessive soil moisture or waterlogging is almost always the cause of root rot in houseplants. However, Overwatering is a common cause of dieffenbachia root rot, which should be no surprise.
When watering your Dieffenbachia, you run the risk of clogging the soil’s drainage system and causing root rot.
In the absence of oxygen, the roots cannot survive in waterlogged soil and drown, decay, and die.
Roots, like us, require oxygen to grow, heal, and function properly.
Overwatering can encourage the growth of fungi that thrive in moist conditions. Root rot occurs when they infect the roots in wet conditions.
Solution
Before watering again, wait until the growing medium’s surface has completely dried out.
Allow the top two inches of soil to dry out a little between waterings to avoid overwatering. A finger test may be helpful in this situation.
In all likelihood, you did not purposefully overwater your Dieffenbachia. As a result, situations that led to overwatering must be rectified:
- Place your plant in a warmer, sunnier spot where it’ll receive plenty of bright light
- Increase air circulation to reduce dampness and encourage the soil to dry out
- Improve soil drainage through either repotting or increasing drainage holes
Of course, you must treat root rot (More on how to do this ahead)
[2] Poor Drainage Causes Waterlogging
Waterlogging is exacerbated by poor drainage. It’s more likely to cause soil to become saturated or soggy than overwatering.
Water should flow freely through the potting mix in a well-drained area, preventing it from becoming saturated or soggy.
However, soils with poor drainages, such as those with a high organic matter or clay content, will retain water for a long time.
Therefore, a combination of too much water and poor drainage results in waterlogged soil, leading to root rot.
Drainage holes in the pot’s bottom can also cause poor drainage.
Water drainage can also be affected by the type of pot used. For example, glazed ceramic and plastic containers tend to retain water for a longer time than unglazed clay or terracotta pots.
Solution
The best corrective solution targets the actual cause of poor drainage.
Start with the pot:
- Does it feature sufficient drainage holes? If not, use a new pot with drainage holes or drill them into the current container.
- Is it made of poorly-draining material like glazed ceramic or plastic? If yes, switch to a high-quality terracotta pot (Check the latest price on Amazon here).
- Does it have a blockage at the bottom? If yes, use a tool to release the blockage and allow excess water to run out of the base without obstruction.
Next, examine the soil’s drainage quality. To improve drainage, repot in a well-aerated, fast-draining soil rich in peat and drainage materials such as pumice, perlite, and so on. You can make use of:
- Pure peat, or
- A mixture of 1 part perlite and 1 part peat, or
- A mix of 1 part soil, 1 part peat, and 1 part vermiculite or peat.
[3] Wrong Size Pot Causes Erratic Drainage
Dieffenbachia’s lifeblood is the pot. It is where it gets its water, food, and other necessities. As a result, you may be tempted to pot your plant in the most enormous container you can find.
Big blunder.
A pot that is too large keeps moisture away from the root ball. This causes water stagnation, which provides ideal breeding conditions for root rot-causing fungi.
On the other hand, a too-small container will result in roots clustering together. Overcrowding of roots not only causes erratic drainage but can also result in root bruising and damage.
It also weakens your Dieffenbachia, making it more susceptible to fungal infections.
Solution
You must move your Dieffenbachia to a suitable size pot. It should not be more than 2 or 3 inches wider than the root ball.
Furthermore, remember to repot your Dieffenbachia every 1-2 years in a pot 1-2 sizes larger.
[4] Fungal Diseases of Dieffenbachia
All cases of dieffenbachia root rot are usually caused by fungus. While most fungi that cause root rot are soil-borne, they do not attack until excessively wet conditions.
Unfortunately, excessive soil moisture wreaks havoc on the roots and opens the door for fungal infections.
Fungus spores can enter through wounds caused by fertilizer burn, cold injury, or other types of root damage.
These fungi often enter the medium via instruments, potting soil, or old pots that have already been infected with root rot pathogens.
If you’re looking for the specific pathogen, I’ve listed a few well-known fungi that can cause dieffenbachia root rot below.
| Fungus Name | Description |
| Phytophthora spp. | The most common cause of dieffenbachia root rot is Phytophthora. Most plant parts are affected, including the roots, stems, and leaves. Prevalent in cold environments. |
| Colletotrichum spp. | Colletotrichum fungus primarily affects foliage, causing tan, water-soaked lesions on leaves edged in yellow. It usually infects a dieffenbachia after being harmed by chemicals or fertilizer. Anthracnose leaf spots can spread downward and cause root rot. |
| Fusarium spp. | Pythium fungus is to blame. Fusarium solani or Fusarium oxysporum are the two most common types of fusarium. Symptoms include purple or reddish discoloration on affected parts and soft and mushy stem bases. In addition, concentric, target-like dark and light rings appear on affected leaves. |
Solution
A spray of copper-based fungicides or sulfur can be used to manage, control, or treat fungal diseases. Use a commercial fungicide labeled for the specific fungus, such as Fusarium spp., Pythium spp., or Phytophthora spp.
Sterilize your gardening tools and old pots before use to prevent spread.
Sanitation and hygiene can go a long way.
Increase the spacing between your houseplants and improve aeration.
[5] Low Temperatures and Frost Encourages Root Rot
The majority of the fungi that cause root rot are opportunistic pathogens. They usually infect the root system, which has already been weakened by frost and cold drafts.
Furthermore, low temperatures discourage soil drying, increasing the likelihood of overwatering. Under low-temperature conditions, your Dieffenbachia will also use less water.
Solution
Transfer your Dieffenbachia to a warm environment where temperatures stay between 60-75°F (15-24°C)
Remove your plant away from cold drafts, such as near windows during winter.
[6] Watering During Dormancy
The majority of dieffenbachia species hibernate in late autumn or early winter. When temperatures fall below 60°F (15°C), they will likely defoliate lower foliage and take on a palm-like appearance.
In this state, it almost wholly eliminates water absorption and usage. You risk waterlogging and root rot if you continue to rinse your Dieffenbachia.
Solution
Minimize watering once your Dieffenbachia goes dormant in winter.
Allow the first two inches of soil to dry out between waterings thoroughly.
How to Save Dieffenbachia from Root Rot
1. Stop Watering Immediately
The more you water your Dieffenbachia, the worse the root rot becomes.
2. Cut Away Affected Parts
Prune out all affected stems and foliage from your Dieffenbachia. Use sterilized pruners or shears and sanitize them after each use using a bleach bath.
3. Unpot Your Dieffenbachia
Remove the affected Dieffenbachia from the pot and clean the root system with water. Then, brush away the soil with a soft brush.
4. Trim off the Affected Roots
To remove all infected or dead roots, use sharp, sterilized scissors or shears to prune the root edges. Don’t be afraid to remove as many roots as necessary.
This is because decayed roots that are not removed will continue to wreak havoc on your Dieffenbachia.
5. Final Touches
You cut down your Dieffenbachia to half its original size. This reduces the number of leaves that require assistance from the healing root system.
6. Prepare the Pot
To reduce the likelihood of reinfection, use a new pot. However, if you intend to use the old pot, make sure to sterilize it by immersing it in a bleach solution. Make the solution by combining one part bleach with ten parts water.
Allow the pot to dry completely after thoroughly rinsing it.
7. Repot Your Dieffenbachia
It will aid in treating the remaining root system with a fungicide dip. Wait 24 hours after applying the fungicide before repotting your Dieffenbachia. Then, use a well-aerated, fast-draining peat-based potting mix. (Check the latest price on Amazon here).
8. Watering after Repotting
After irrigation, establish an appropriate watering routine. Dieffenbachias dislike standing on wet feet, so the soil should never be wet or soggy.
9. Caring for Dieffenbachia after Repotting
- Increase air circulation
- Plenty of bright, indirect sunlight
- Warm temperatures between 60-75°F (15-24°C)
- Avoid wetting the leaves or overwatering
- Place away from houseplants that may have pests or diseases
- Don’t disturb your plant and give it time to adjust to its new growing medium
Last Resort: Propagating Dieffenbachia
Unfortunately, if root rot has destroyed most, if not all, of the Dieffenbachia’s roots, it cannot be saved. In that case, propagating a new dieffenbachia is your last resort.
You can accomplish this in three ways:
(A) Propagating Dieffenbachia with Cuttings
This is the easiest and most effective way to propagate a dieffenbachia.
- Take several pieces of cane cuttings from a healthy dieffenbachia
- Keep the cuttings in clean water until the roots sprout.
- Leaves will slowly grow as the cane cuttings take roots
- Transplant the cuttings once they have enough roots
(B) Propagating a Dieffenbachia Stump
- Cut off the top of a leggy, older Dieffenbachia (aka the stump)
- Apply rooting hormone to cut site
- Plant the stump in fresh potting soil
- Remove older leaves once new ones appear
- Provide standard care and growing conditions
(C) Propagating by Root Divisions
- Take root divisions or offsets from a healthy mother plant
- Be gentle lest you damage the parent dieffenbachia root system
- Use sterilized instruments when dividing the root divisions
- Plant each root division in its own pot
- Water thoroughly and place in a warm, brightly-lit environment
Treating Dieffenbachia Root Rot with Chemical Fungicide
Dieffenbachia root rot is frequently caused by a fungus, as we’ve seen, so fungicides are a logical and practical solution. However, it’s best not to use chemical fungicides until you’ve identified the specific fungus that’s causing the problem.
Dieffenbachia plants need to be tested for the fungus by a plant doctor or nursery. Then, you’ll be able to identify the fungus causing the problem and select the most effective fungicide that way.
If the pathogen causing your Dieffenbachia’s root rot can’t be identified, chemical fungicides aren’t a good idea.
On the other hand, chemical fungicides can be pricey and require extra caution when used.
This plant is susceptible to root burn caused by chemical fungicide contamination of its growing medium. It’s funny how that works, don’t you think? Fungicide label instructions must be strictly followed, so use them as directed.
Homemade Fungicides for Treating Dieffenbachia Root Rot
With so much uncertainty surrounding the use of chemical fungicides, it’s a no-brainer to turn to home remedies instead of purchasing store-bought ones.
To treat or control root rot in my dieffenbachias, I frequently use the following everyday household items:
Charcoal
Activated charcoal is a home remedy workhorse. It also happens to be an excellent natural antifungal. In addition, it’s quite porous, repels pests, and absorbs odors.
Activated charcoal can also be used to prevent mildew and mold growth.
Before repotting your Dieffenbachia, sprinkle a thin layer on the bottom of the container.
Cinnamon
Cinnamon has excellent antifungal properties, plus it’s non-toxic, widely available, and repels fungus gnats.
Before repotting, sprinkle cinnamon powder over the trimmed healthy roots.
Chamomile
Like cinnamon, chamomile has antifungal properties. However, Dieffenbachia must be applied to in the liquid form.