It means the stump is decaying, which is what you want

Mushrooms on a stump are a sign the wood is breaking down. That is the process you are waiting for if you left the stump, and it is not, by itself, a problem. Georgia humidity and the run of warm wet weather from May through September makes it near universal here.

The fungus is not attacking your lawn and it is not attacking your house. It is eating dead wood, which is its job. A stump with heavy fungal growth is further through decay than a clean one, which means it is closer to being gone.

There are two situations where it does matter.

The first is if the mushrooms are appearing on living trees nearby, not just the stump. Some wood decay fungi, armillaria in particular, can move through root contact between trees. If you are seeing honey-coloured clusters at the base of a healthy oak twenty feet away, that is worth an arborist looking at rather than a stump grinder.

The second is simply children and dogs. Plenty of the fungi that colonise stumps are unpleasant to eat and a few are genuinely dangerous. If the stump is in a garden where either spends time unsupervised, that is a practical reason to remove it that has nothing to do with the health of anything.

Grinding removes the fruiting body and most of the food source above grade, which usually stops the flushes. It does not sterilise the soil, and you may still see the odd mushroom over the buried roots for a year or two afterwards. That is normal and it stops.

What does not work: bleach, salt, or fungicide poured on the stump. It kills the visible mushrooms for a fortnight and does nothing to the mycelium doing the actual work, while the salt does real damage to whatever you want to grow there afterwards.

More on stumps

• Yes, but the distance to your house is what matters A rotting stump near a Georgia house is a genuine termite question, but not for the reason most people assume. What actually matters and what does not.
• Most of the internet advice on this is wrong Epsom salt, burning, stump killer, renting a grinder. An honest look at each, including the two that genuinely work and the conditions they need.
• Any month works. Some months cost less Grinding works year round in north Georgia, but scheduling, price and ground conditions all move with the season. When to book and when to wait.
• Do not backfill with the chips. That is the whole lesson Grinding leaves a mound of chips and a void underneath. What to backfill with, why not to use the chips, and how to get grass growing over it.
• Where the trunk stood decides it, not where the branches were Whose stump is it when the tree straddled a boundary, what Georgia practice generally holds, and the practical way neighbours sort it out.

By tree

• Loblolly pine
• Sweetgum
• Water oak
• Bradford pear
• Leyland cypress
• Crepe myrtle
• River birch

Stump services

• Full stump removal
• Grinding vs removal
• Large stump grinding
• Multiple stumps
• Surface root removal
• Storm damage stumps
• Grinding before a fence, pool or driveway