Hopefully you've destroyed it and used some copper sulfate on the soil there.

"Hopefully you've destroyed it and used some copper sulfate on the soil there."

This is NOT good advice. Judging by your picture, that looks like some typical stipitate basidiomycete (gilled mushroom). I can't ID it without some more specific information and/or better pictures. If you want to know exactly what it is, I'd be happy to help you ID it.

If you just want to know if it's dangerous for yourself or your plants, I can probably help right here.
First, is it actually growing on the plant's roots? It doesn't look like a parasitic fungus to me, but it still could be. It is much more likely to be digesting wood dropped from your plants, or other random organic debris, which would be considered a GOOD thing, as it makes previously unavailable nutrients available to your plants.
If it is growing on the roots, it may be parasitic, but it's more likely to be a mycorrhizal fungus, which is one that forms a mutually beneficial relationship with a plant's roots. Basically, many fungi and plants intertwine underground and exchange nutrients with each other, helping each other stay alive and flourish. In fact, most flowering plants have mycorrhizal relations with at least one (and sometimes over 20) fungus. Many plants cannot live without them.

As far as your health goes, I highly suggest that you do not eat it, but if animals are eating it, it's likely to not be deadly. It still may cause severe gastrointestinal distress in humans, making you wish you were dead.

Concerning copper sulfate: it is a potent fungicide, commonly used to kill parasitic fungi on plants. However, even if this is a parasitic mushroom, treating the soil in your garden with copper sulfate is a bad idea, because it will kill off ALL of the fungi (and many other microorganisms) in your soil, which are super necessary to break down organic material and make it available to your plants, as discussed earlier. If you compost in your yard, fungi and bacteria are vital, and copper sulfate will ruin that.
It is also used as an aquatic herbicide and a pesticide, so it's obviously just generally poisonous.

Here is a link that might be useful: how to id a mushroom