Practical Guide to Identify, Treat and Prevent Dieffenbachia Root Rot

If you suspect Dieffenbachia (aka dumb cane) root rot is setting in, you need to quickly identify, investigate and treat the disease before it takes hold of your beautiful houseplant.

Symptoms of root rot include:

Dieffenbachia rotting or mushy stem that also emits a foul odor,
yellowing leaves that appear droopy (sometimes with black or brown spots), and
your Dieffenbachia is constantly sitting in soggy soil with little to no noticeable growth.

If any of the above symptoms sound familiar, your Dieffenbachia may be at risk of root rot. To confirm your suspicions, you will need to get up close and personal with your Dieffenbachia’s root system. Identify any rotting roots, and immediately prune and treat. Even out the plants’ foliage up top to give your plant the best opportunity for a successful recovery, and repot into a completely sterile new home.

If you are feeling a bit daunted at the moment, we don’t blame you.

But, don’t worry. We’ve put together a practical guide to help you confidently identify infected roots using a 3 Test System. We’ll also lead you through the process of treating root rot using easy to follow steps (even for beginners). And finally, we’ll round off the guide with ways to prevent root rot from attacking your houseplants in the future.

If you’re ready, grab a coffee because we’ve got some work to do!

How to Inspect Your Dieffenbachia’s Root System

Like we said earlier, in order to salvage your Dieffenbachia, we are going to need to get our hands dirty and take your plant out to examine the plant roots.

If you have never taken a plant out of its pot before, the first time can be intimidating. Don’t be concerned – we’ve anticipated this with a quick guide of how to safely depot a plant:

If you have a plastic pot, gently squeeze the sides of the container to loosen the plant from the pot. If your plant is in a ceramic or solid pot, you can skip this step.
Spread your hand over the surface of the soil, placing the main stems of the Dieffenbachia snugly between your fingers to support the plant as it comes out of the pot.
In a smooth swift action, tip the pot upside down. You’ll feel some topsoil fall down – which is normal. Depending on how long your Dieffenbachia has been in the pot, it should stay in the pot.
Gently coax the plant out of its pot but shimmying it out of its home. As the Dieffenbachia comes out, you should begin to feel the weight of the plant on your hand that was covering the soil. Be careful not to crush the stems as you move the plant out.
Remove the root ball from the pot, and you have successfully extracted your first ever plant.

3 Test System for Identifying Dieffenbachia Root Rot

One of the first steps in getting your Dieffenbachia back on the road to recovery is to prune away the rotten and infected roots. But how do you know which roots to trim?

To answer this question, we have developed a 3 TEST SYSTEM to help you determine which roots to discard.

Root Rot Visual Test

For the first test, you won’t need to get your hands dirty. It is a simple visual inspection of the roots’ system. What you are looking for are roots that appear rotting or discolored (when compared to healthy roots).

Rotting roots will appear dark (almost black) and mushy.
Healthy roots are usually white, light brown or sometimes a light green color, they will also appear strong and plump.

You’ll also be able to tell healthy living roots by the way they are gripping onto the surrounding soil. Rotting roots will usually have loose soil falling or crumbling away.

Root Rot Smell Test

Once you have identified any suspect roots, you can move onto the next test – the sniff test. Yes that’s right – we’re going to be getting up close and personal with your Dieffenbachia’s roots.

Sniff the areas of the roots that you suspect may be infected by root rot. Healthy roots won’t smell, and you should only get wafts of that all too familiar fresh soil smell. Whereas, roots suffering from root rot will smell off with a foul odor.

Root Rot Touch Test

Finally, to confirm that the smelly, rotten looking roots are in fact infected with root rot, the next step is to squeeze them.

Test the integrity of roots by pinching them between your thumb and index finger with medium pressure. A strong healthy root should be firm to the touch, and should not have any give when squeezed. Rotting roots will be soft and mushy roots, and may even break off when pinched.

Remember to wash your hands with soap after performing the touch test. Root rot is a disease that can be transferred to other plants.

How to Treat Dieffenbachia Root Rot – Step-by-step Guide

Now that you have confidently identified the affected roots, you can begin the next step in the process – treating and eliminating root rot from your Dieffenbachia.

Here is a step-by-step guide for treating root rot in your Dieffenbachia:

If you haven’t already, use the above instructions to carefully remove your plant from its pot.
Loosen the soil from the root ball. Make sure to do this over a plastic bag or container, because we will be discarding ALL the infected soil. Thoroughly clean all the roots by gently washing the roots under warm tepid water from a tap.
With a hydrogen peroxide or bleach solution, wash the old pot and any gardening tools to kill pathogens and prevent the spread of fungal spores. The solution is made by mixing one part bleach with two parts water.
Sterilize sharp scissors with rubbing alcohol. Use the clean scissors to cut off all the brown, rotting dead roots that were identified earlier. The goal is to eliminate all the root rot disease, but retaining as many healthy portions as possible. Remember to re-sterilize your gardening scissors after use to avoid cross-contamination.
Pour fungicide solution over the remaining roots to kill root fungus and prevent another infection. An alternative to fungicide is a hydrogen peroxide solution (mix one part bleach with 15 parts water).
This step is important. You will need to remove the same proportion of foliage from the top part of the Dieffenbachia, as you did with the roots’ system. For example, if you removed a third of the roots, remove a third of the leaves. This will aid in the recovery process, and not over burden the remaining healthy roots.
Re-pot your Dieffenbachia into a NEW container with sufficient drainage holes. Use fresh potting mix that has good drainage properties. We like to make up our own indoor plant soil using our recipe to ensure our indoor plants have soil that drains well, but also retains enough moisture to thrive.
Finally, make sure to feed your plant with fertilizer and essential nutrients. It will need it to recover and grow stronger than before.

And that’s it – easy as pie right? We’re sure it took a bit of time, but it will be well worth the effort and time to salvage your ailing Dieffenbachia plant.

How to Prevent Dieffenbachia Root Rot

As we always advocate at the Garden Bench Top, the best way forward is prevention – and the only way of preventing root rot is understanding the causes.

Here are a few common causes of root rot:

Overwatering Causes Root Rot

How often are you watering your houseplants?

Do you check the soil before topping up the water?

Overwatering your plants is one of the biggest causes of root rot. The reason is the disease requires a constantly moist environment to grow and spread from root to root. And the soil in overwatered indoor plants is the perfect environment. It stays wet for days (if not weeks), with little to no disturbances and temperature fluctuations.

The solution is easy right? All you need to do is water your plants less. But how do you know when to water your plants?

The answer is adjusting your habits and TESTING YOUR SOIL before you add water.

Always test your soil BEFORE adding more water.

There are a few ways to go about testing for excess moisture levels in your soil. Those that are short on time, or prefer to use gadgets, can use a soil moisture meter.

If you don’t mind getting your hands (or in this case, fingers) dirty, we recommend using the soil moisture finger test. It only takes a few moments to see if the soil is dry, and it has always been a reliable indicator of our plants’ water needs.

Insufficient Drainage

Soggy wet soil isn’t always caused by overwatering. If there is insufficient drainage in your pot, this can also lead to root rot.

Poor drainage can be the result of :

pots with too few or no drainage hole,
poor quality soil mix that is too dense and heavy, which will hold onto water and result in a lack of oxygen flow, and
non-porous pots (such as plastic) will keep water in the container and lead to wet, waterlogged soil.

The solutions to these problems should be relatively simple to implement. Make sure your planters have enough drainage holes at the bottom. You can change your Dieffenbachia plant’s pot or engage in some DIY by cutting more drainage holes yourself.

Always use soil that has good drainage properties, but also has water retention capabilities. We like to use a combination of coco coir (for water retention), perlite and vermiculite (for aeration and drainage of excess water) for indoor plant soil.

Stressed Plants

Plants that are stressed are more susceptible to diseases, like root rot and pests.

A stressed plant is a weak plant, which means it is easier for root rot to set in and take over the entire root system.

Plants can be stressed by many factors, such as :

inappropriate lighting conditions,
over and under watering,
changes in humidity and temperature, or
even overfertilizing your plant can cause it to become stressed.

Frequently Asked Questions about Dieffenbachia Root Rot

In this section we’ll answer all your ‘other’ questions that may not be addressed in this guide.

If you can’t find an answer to your question, please send us a message via our CONTACT page. We will endeavor to respond with a timely answer, and include it in our growing FAQ section below.

How do you heal Dieffenbachia root rot?

Quick and decisive action will heal your Dieffenbachia from a bout of root rot. Quickly identifying the source of the root rot and separating it from the main plant will help reduce the spread. You will also need to treat the remaining healthy roots with a fungicide (or hydrogen peroxide alternative) to completely eliminate the disease.

By following this easy to follow guide, you’ll have your Dieffenbachia back in recovery mode in no time.

What does an overwatered Dieffenbachia look like?

Overwatered Dieffenbachia plants are easy to identify. They will appear limp with discolored yellow leaves. Overall, they will appear sad and lifeless, as opposed to the normal vibrant plants that they are well known for. The soil will be soggy and wet, with a rotten smell emanating from the topsoil.

When is a Dieffenbachia not salvageable?

Advanced root rot infections occur when disease has infected the stem of the plant. You will be able to identify this by the Dieffenbachia rotting stem or mushy stem.

When you see this symptom, the root rot is too advanced and has likely infected the entire root system.

If your Dieffenbachia has reached this stage, the best option is to try propagating any healthy parts of the plant, or sending it to plant heaven.

– Dieffenbachia Root Rot –