Mrs. Jess Walton of Marlow Heights, Md., writes: I do not know how to take care of the Chinese evergreen plant that I received for Christmas. Two leaves have turned yellow; so I must be doing something wrong. Please advise.

There are several varieties of Chinese evergreen, differing mainly in height and variegation of leaf pattern. All of them thrive in low light. A north window is a good location. Chinese evergreen will grow in either water or soil. If in soil, water it thoroughly and then let it become almost dry before soaking again. Spray-mist the leaves frequently with tepid water. Occasionally wipe dust from leaves with a moist sponge or towel.

As a gift plant, your Chinese evergreen probably came from the florist; if so, it will not need fertilizer until April or May; you can give it monthly feedings of liquid houseplant fertilizer during the spring and summer months.

The yellow leaves may be due to over-watering or they may have resulted from the reduction in amount of light and humidity since it left the florist's. Chinese evergreen is a very tolerant plant and should soon adjust to your home environment.

Hazel Harvey of Frederick, Md., enclosed leaves from an old schefflera. It had been cut back severely because of an infestation of spider mites but seemed to be rejuvenated outdoors during the summer. Since coming inside it has some new healthy shoots but the old leaves look like those enclosed. It is watered about once a week and fertilized every two or three weeks. Could you help?

Unless your plant is in active growth, putting out new leaves, withhold the fertilizer. With the reduced intensity and duration of light during winter months, plants become dormant or partly so and so require little or no fertilizer. Use a water-soluble fertlizer monthly from spring to fall. Damage to the leaves may be from fertilizer or from the reduced amount of light.

Celia Kaplan of Chevy Chase, Md., writes: Could you please give me instructions on how to keep large plants at a reasonable size? I have a dracaena marginata and schefflera both getting too tall.

One means of restraining plant growth to prevent a plant from becoming too large for its alloted space is to keep it in a small pot. Limited root space and soil nurients retard growth. Withholding fertilizer or reducing frequency of feeding is also effective.

Dracaena marginata can be cut back to force sprouting from lower portions of the cane. The upper part can be used as stem cuttings to propagate more plants. This is a rather radical treatment.

Schefflera can be reduced in size by pruning. Cut off the tips of stems just above the point where the leaf is attached. Branches that extend too far can be cut back in this way until you achieve the symmetry which pleases you. A new branch will grow from the point where the cut is made.(TABLE) My palm, which I have had 10 or 12 years, has grown and been very healty until this past fall. It started getting white streaks on the fronds, which in time turn brown and die. The location of the plant, light conditions or watering practices haven't been changed. I hope you may be able to tell me what is wrong.(COLUMN)According to the handbook, "Cultivated Palms," among the few pests that afflict household palms are mites, known also as red spiders, mealy bugs, and scale. When leaves lose their green color and turn brown, you may expect to find mites, especially if the air is dry.(COLUMN)Mites are nearly invisible. Hold a piece of white paper under the leaft, tap the leaf, and the little brown, red or black pests will appear on the paper like specks of pepper.(COLUMN)Spray the entire plant with a miticide, a product specifically for control of mites, available at garden centers. Give special attention to the underside of leaves. Repeat twice at four-day intervals to get complete control.Malathion and other insecticides may have no effect on mites. In using pesticides of any kind, read the label and follow the manufacturer's instructions. (END TABLE) CAPTION: (TABLE) Picture, no caption, By Ronalie C. Peterson for The Washington Post(END TABLE)