Patricia Brown of Columbia, Md., writes:

I have the strange problem of having too much success with my heartleaf philodendron. It is full on both sides, has 10 to 12 active vines at the top, is 6 feet tall and lives indoors all year long.

It continues to grow above the wood bark and begins to look sloppy, hanging at all angles. I have trimmed it back as far down as I could without demanging any of the imbedded roots. How can I prohibit growth above the bark without continuous cutting? How can I encourage branching and growth farther down the bark pole?

It is the nature of the heartleaf philodendron to vine. It will continue to produce new shoots when pruned as long as you do not destroy the bud at the point where the cut is made. Cutting the vine below the leaf axil where the bud grows should force a bud lower on the vine to grow.

If there are several rooted vines growing up the pole, select a point on one of the vines about midway of the pole and sever it just above the point where a leaf joins the stalk;a bud at that point should break in a short time.

If you keep the bark pole moist all the time, the severed vine may continue to get enough moisture and sustenance from the pole to live. If not, it can be cut in pieces for propagating new plants. If there is only one rooted vine growing on the pole, make cuttings of the pieces trimmed from the top and start some new plants to be planted in the same pot.

For Fran O'Neill of Bethesda:

The following is in answer to your several questions about published articles.

For the publication about how to make a vegetable garden, call your county agricultural extension office, 948-6740, or write to Office of Communications, U.S. Department of Agriculture, Washington, D.C.

I am not acquainted with the brochure from the van lines about moving plants.

Sources of Oxalis are: Bittersweet Hill Nursery, Davidsonville, Md. (telephone 301-798-0231); Logee's Greenhouses, Danielson, Ct., 06239; Behnke's Nurseries, Beltsville, Md.; Geo. W. Park Seed Co., Greenwood, S.C. 29647.

To readers asking for sources of Papyrus:

A communication form the Greensleeves Plant Store, 503 Maple Ave. W., Vienna, Va. 22180, informs me that Cyperus papyrus is obtainable there. The source previously listed in this column was Three Springs Fisheries, Lilypons, Md.

Another form of Cyperus commonly grown as a houseplant is the umbrella plant, Cyperus alternifolius or Cyperus alternifolius gracilis. Dwarf umbrella plant is Cyperus diffusus. The umbrella plant can be purchased at Flowers & Plants Etc., 1378 Chain Bridge Rd., McLean, Va. 22101.

Papyrus is an aquatic grass native to southern Europe and Egypt. The umbrella plant is not as tall as papyrus; it is a semi-aquatic tropical species from Africa.

Cyperus species do best where they get 4 or more hours of direct sunlight each day; the soil must be kept wet, usually by setting the pot in a container which will hold water.

Richard L. Schmidt of Arlington writes:

My Norfolk Island pine appears healthy and has developed several new sets of branches. However, it persists in dropping its lower branches. The plant is presently on a porch that is shaded most of the day.

Light level may be the problem, as your letter suggests. These plants like a bright location with 3 or 4 hours of direct sunlight a day. Since your plant is growing on a shaded porch, do not move it immediately into a sunny spot; it should be gradually accustomed to an increased amount of light.

Norfolk Island pines prefer a cool location, but they will tolerate a range from 45 to 85 degrees F. Indoors you should make provision to increase the humidity immediately surrounding the plant by setting the pot on a saucer or tray of pebbles that are kept constantly moist; the diameter of the saucer should be greater than that of the pot so that moisture from the pebbles, evaporating, moistens the air round the pot; do not set the pot in water. Low humidity and high temperatures indoors are frequent causes of the loss of lower limbs or browning of the tips on Norfolk Island pine.