Hi and
Trebeca. You're going to get more questions than answers first, as we need more info on your tree and your situation. A picture of the tree and the area you want to plant would be very helpful, too.
Whereabouts in the country are you? (you can enter this info, city and state is enough, in your personal profile so it will come up on all your posts) We need to know this before recommending what you might plant.
How big, or how old is your holly tree? Is it in full sun? Does the sun get underneath, to where you want to plant?
What do you like to eat from the garden?
First thing that comes to mind is, don't forget your holly tree will have an extensive root system spreading out generally at least as far as the branches reach. So you may be able to grow some herbs or other hardy things near it, but fruits and veggies need a lot of water and nutrients to produce, and they won't want to share with your tree.
