I live in a rather small townhouse with a small front & back yard.  There is no grass in the back yard, but rather a cement patio surrounded by brick pavers.  Although plenty of grass and weeds pop up between the cracks of the pavers, this provides no natural habitat for plants.  Instead, I purchased several whiskey barrels that have been cut in half.  These make for wonderful planters, but they can be hard to find - unless you happen to live near the Jack Daniels distillery.

These planters have a distinguished, almost antique look and they are perfect for small gardening needs.  And if you are strong, they are even somewhat portable while in use - which can come in handy.  I've used them to plant herbs and flowers, but you could easily use them for small trees, bushes or even vegetables.