Eileen Kozak of Arlington writes:

About a year ago I bought a grafted cactus called a "Moon Cactus." It now has two flowers as well as many little round "babies" along its ridges. It is top heavy and probably needs to be repotted. I have no idea what potting medium to use. I am also curious as to whether new plants can be started from the "babies."

A. Grafted cacti, combining two different cacti into one plant, are increasingly popular as novelty plants. Cacti are usually grafted because the top plant is a week grower on its own natural roots. Grafting it onto a vigorous growing base will make the top plant healthier and faster growing.

Resources available to me fail to disclose a cactus listed as "Moon Cactus." Therefore I cannot respond specifically on the care of your plant.

Some species of cactus develop young plants all over the body of the parent. In these cases, the small plants generally break off readily and can be rooted easily. Often they will have grown roots while still attached.

Sand, pumice, cactus soil mix or vermiculite can be used for rooting. A mixture of sand and vermiculite is excellent as it is sterile and drains quickly but holds enough moisture to start the rooting process.

It is time to repot, when the plant is top-heavy or when roots entirely fill the pot. In transplanting, set the plant at the same level as in its previous pot and fill in with damp cactus soil mix; do not water; wait several days to a week to allow time for any damaged roots to heal; water sparingly for the next few weeks.

Eileen Kozak, Arlington, asks:

My asparagus fern has grown too large for the space in my home. Is there any way to split it or cut its roots back?

A. Asparagus fern is usually only repotted when it literally bursts its pot. Sometimes it will fill the pot with roots until the plant rises an inch or more above the rim of the pot and the thick roots are clearly visible. The roots adhere to the inside of a clay pot so that it is necessary to pry them loose; you may have to break the pot.

Cut off the fronds in preparation for repotting. If you want to divide the plant, simply cut the fleshy roots apart with a sharp knife and plant the pieces individually. A packaged general purpose potting soil is satisfactory; use a clean pot and provide drainage material in the bottom. Water thoroughly and set out of direct sunlight for a few days. Do not feed newly potted plants.

If you do not wish to divide the plant, you can reduce its sizes. Cut off the fronds and remove the plants from its pot. With a large sharp knife, ruthlessly reduce the size of the root ball by cutting off an inch or so all the way around. Then the smaller root ball can be set in a clean pot of the same size as it previously occupied, and supplied with fresh soil.