Q A previous owner of my home planted many named varieties of roses. Subsequent owners failed to care for them. While a few of the lovely varieties have survived, most of the remaining roses appear to be rootstock only. Is it possible to graft known varieties onto these wild rootstocks or should I remove them and start over? L. M. Nevada City, Calif. While it is possible for amateur rose growers to bud or graft rose varieties onto a rootstock, it takes know-how, compatible weather, and rootstock that is in good condition. You could get a bulletin with illustrations from your state college, if you want to experiment, but since your rootstocks are obviously several years old, it would be better to discard them and set out all new plants. Q We have a new puppy and two kittens and they are determined to chew on our plants. A friend has told us to keep our philodendrons out of reach because they are toxic. Could you comment on this and also tell us the names of a couple of types of plants that would be perfectly safe for them to chew on? We thought we might set a couple on the floor especially for our pets. M. S. Lincoln, Neb.
It is best to keep philodendron, dieffenbachia, and pothos (Scindapsus) out of reach of pets and small children. Spider plants (Chlorophytum, any variety) are especially loved by pets and are perfectly harmless for them to chew on. Even pet birds like them. Also, any of the thin-leaved dracaenas fulfill a need for green grassy foliage. Most pets in northern areas have little access to green plant growth during winter, and you'll do your pets a favor by providing some indoors. Even a pot of wheat or oat seedlings will provide a treat for your pets. Q We have a lemon tree grown from a seed. It is now six years old and four feet tall. What should we do to induce bloom and fruit set once it begins to bloom? A. K. Huntington Station, N.Y.
Citrus started from seeds are often stubborn bloomers. If you could move the tree outdoors during summer where it will get bright sunlight and you can keep it watered adequately, it may induce the fragrant blooms to form. If blooms do form and you do not have any bees for pollination, use an artist's paintbrush (or the tip of your finger) and transfer pollen from one bloom to another. Q For a number of years I have noticed a gray-green algae-like growth on the bark of many of my trees. I find it on all sides. Is it harmful? A sample is enclosed. C. L. Summit, Mo.
Your sample of bark contained a lichen, a curious flowerless plant which hugs rocks, tree trunks, and limbs. Within a lichen is an alga and a fungus which live together in a symbiotic relationship (the fungus supplies the water, the alga the food). Lichens are harmless to trees but may cause rocks to slowly disintegrate, changing them into soil. There are more than 2,000 species of lichens in North America, many of them used for dyes.
If you have a question about your garden, send it to the Garden Page, The Christian Science Monitor, One Norway Street, Boston, Mass. 02115.