Houseplants need pruning below ground too

A special type of pruning that houseplants need is root-pruning. Once a plant has grown as large as you want it to, the soil must be periodically renewed around its roots. The only way to accomplish this without increasing the size of the pot is to cut back some roots.

Depending on the vigor of the plant, root-pruning might be needed once a year or every few years. Determine when root-pruning is needed by knocking a plant out of its pot and looking at the roots. If they are going around and around in a thick mat at the surface of the root ball, root-pruning is needed. Or, the plant might call out by itself for root-pruning with a mass of roots sneaking out the bottom of a pot, futilely in search of new soil.

To root-prune, either tease long roots away from the root ball and shorten them, or else slice pieces of soil and roots from the edge of the root ball with a knife. After slicing, loosen up the remaining roots at the outside of the root ball. Return the plant to its pot and pack fresh soil in around the root ball.

Once the plant is back in its pot, the stems also will need some pruning to keep the top of the plant shapely and in proportion to the size of the container. The goal here is beauty, not growth. After all, you're not seeking maximum growth from a houseplant that already is full size -- full-size for your house, that is.

The techniques for pruning the stems of any houseplant are the same as for pruning its full size counterpart in the wild, except that you prune more severely indoors. Shorten stems and pinch out the tips of growing shoots where you want branching; more bushy growth results from the awakening of buds below such cuts. Where growth is too dense and you do not want branching, cut away whole stems at their bases. Regrowth rarely occurs where you remove a whole stem. To drastically lower an indoor tree, shorten major limbs to side branches within the crown, just as you would on an outdoor tree.

A difference, from your point of view, between working on the houseplant and the full-size versions of a tree, shrub, or vine is that with the houseplant the work is more intimate. And your feet are on the ground.