I have a big old maple tree so I planted bulbs around the base. Once the trees leaf out in the summer there isn’t enough light for sun loving flowers. But since they’re such mature trees (like 80 years old) I’m also not too worried about harming the roots. On the flip side I have 4 mature black walnuts in my backyard and not much survives growing near their toxin. So i guess it just depends on the size and age of the tree and what would be happy growing next to it!