What are the symptoms of root rot?

Wilting canopy despite watering, yellow or browning leaves, soft or foul-smelling roots, reduced root mass, and brown/black roots; sometimes fungal conks near the root collar.

Can fungal root rot be cured?

There’s no instant cure; focus on prevention and mitigation—improve drainage, avoid overwatering, build healthy soil and mulch, consider air spading or deep-root treatments, and use preventative fungicides when appropriate.

Fungal Root Rot: Signs & Prevention

Q: What is fungal root rot?

A soil-borne disease that attacks tree roots—often in wet, poorly drained soils—and can slowly kill a tree from the roots up.

What Is Fungal Root Rot?

Fungal root rot is exactly what it sounds like - a disease that attacks the roots of trees and plants, caused by non-beneficial fungal spores living in the soil. It thrives in wet, poorly drained conditions, which we see a lot here in Central Texas after heavy rains or in compacted soil.

Once it sets in, it can slowly kill a tree from the underground up, long before most people even know there’s a problem.

Common Types of Fungal Root Rot

There are a few different fungi responsible for root rot. Some go after trees, others hit flowers or vegetables. Here's a quick breakdown:

Phytophthora – The most common one, affects a wide range of plants and trees
Pythium – Hits seedlings and young plants
Rhizoctonia – Shows up in gardens, targets ornamentals and veggies
Fusarium – Mostly found in ornamental plant roots
Thielaviopsis – Affects grasses and ornamental plants

If you have any kind of root decay or yellowing leaves, this could be the reason.

Symptoms to Look Out For

Here’s what we see most often when a tree is dealing with root rot:

Wilting in the canopy (even if you’re watering)
Yellowing or browning leaves
Roots that smell bad or feel soft and spongy
Visible reduction in root mass
Brown or black roots (see image below)
In severe cases — tree death

If your tree is wilting and you're doing everything "right," it might be time to look below the surface.

Signs of Disease

Fungal conks (mushroom-like growths) forming near the root collar
White fungal threads or growth along the fibrous roots
In some cases, the tree may look okay above ground — but the root system is already compromised

Want to be 100% sure? We can send in lab samples from the roots to confirm if fungal root rot is the cause.

How to Prevent Root Rot

There’s no magic spray that reverses root rot once it sets in. The key is prevention by creating conditions where fungi can’t take over in the first place.

✅ Tips to Reduce Root Rot Risk:

Avoid overwatering (let soil dry between watering)
Improve drainage around your trees
Build healthy soil with compost and mulch under the drip line
Deep root injections can break up compacted soil and help improve aeration
Air spading (special equipment we use) mixes and aerates soil around the roots
Use preventative fungicides before you see symptoms

Once root rot hits, it’s about managing the damage, not curing the tree. Prevention is everything.

How Tree Scouts Can Help

Our certified arborists have seen this problem more times than we can count, especially in neighborhoods with heavy clay or compacted soil.

We can inspect your trees, look for signs of fungal root rot, and take soil samples if needed
If we find early-stage issues, we’ll recommend next steps that actually make a difference
If the tree can’t be saved, we’ll walk you through safe removal and how to rebuild the soil for future planting

Our team has the scientific know-how to help diagnose fungal root rot. If its there then we can help you deal with the aftermath of the disease.