Bromeliads
There are literally thousands of different types of Bromeliads available and for the residential gardener they offer a really cheap and easy way to fill in all the empty spots around the garden particularly in the shady areas under shrubs and trees. These plants don’t need to go into soil, you plant them in amongst piles of bark and finer mulch as they feed from the cup in the top of the plant rather than grow a lot of roots.
Hardy and easy to split up and spread around you can often swap them with friends and family rather than buying them