I just bought a Lilac Shrub to plant, and I started in a big pot. It is so small I didn't want to start it in the ground yet, I haven't found a spot where I would like to put it and my neighbour would end up running it over with his lawnmower anyways. Is this a bad way to start it off? When should I replant it in the ground? I wanted to give it a little time to stabilize in the pot before planting in the ground, that way it also gives me some time to think of a good place to plant it.

Thanks for any help.

I don't think it will hurt to grow the lilac in a pot for a while. I've transplanted Lilacs from one yard to another without them being at all bothered by it, so I think you will be fine with your plan to grow it in a pot till you've found a place for it. I've also found that lilacs are pretty resilient, one in our yard was partially run over by a fuel truck, another was chewed and rolled on by two dogs all one summer - both looked a little rough for a year or so, but recovered beautifully.