Q. We want to plant two or three apple trees either this fall or in the spring. Which ones are considered the best? Should we plant regular trees or dwarf ones? Where can we buy them?

A. Ask three different experts their preference on apple trees and you'll probably get three different answers. Northern Spy is a very good one for eating out-of-hand and for applesauce and pies. Some say it's the best ever grown in the United States. Red Northern Spy is not nearly as good. Jonathan is a good one, Rhode Island Greening is a very good one, Baldwin, Red Delicious, Yellow Delicious and Grimes Golden are loved by a lot of people.

Dwarf trees are easy to spray, the fruit is easy to pick, and the trees do not take up as much space as standard ones. You can send for catalogs from Bountiful Ridge Nurseries, Princess Anne, Md. 21863; Stark Brothers Nurseries, Louisiana, Mo. 63353 and Kelly Brothers Nurseries, Dansville, N. Y. 14437.

Q. How old must a pine tree be before it starts to bear cones?

A. The time of cone (see) bearing is determined by age rather than size of the plant. Jack Pine of the Great Lakes area may bear cones when three years old; lodgepole and pitch pine at five or six years; eastern white pine, longleaf and shortleaf pine rarely bear cones until after 10 years. The sugar pines of the west seldom bear cones before they are 40 to 50 years old. Most trees produce their best cones during middle age.

Q. When can we plant our amaryllis bulbs?

A. Early November is a good time to pot them. Give each bulb a 5- or 6-inch pot, with only the lower third of the bulb in the soil mixture. Water well and put in a cool, dark place until the flower bud is well out of the leaves, then put it where it will get good light.

Q. I bought a dieffenbachia plant. It is beautiful, but I am told variegata?

A. Seeds of several colors of Abutilon (flowering maple) are listed in the catalog of Park Seed Company, Greenwood, S. C. 29647.

Q. bought a dieffenbachia plant. It is beautiful, but I am told it may be poisonous. Is that true?

A. Dr. Frederick W. Dehme, Kansas State University Comparative Toxicology Laboratory, conducted tests where animals were fed relatively large amounts of roots, stems and leaves. He found that dieffenbachia, chrysanthemum, geranium, Jerusalem Cherry and philodendron were not poisonous. Similar studies at Ohio State University showed that Poinsettias are not toxic to animals.

Dieffenbachia roots were the only plant parts that caused a reduction in daily weight gain.

To exceed the amount consumed by these test animals, a 40-pound child would have to chew and swallow more than 100 grams (3 1/2 ounce of 7 tablespoons) of ground fresh root tissue.