Q: I read about growing roses without spraying chemicals on them. Isn't that a pipe dream if I want roses without black spot and mildew and rust?
A: Happily, it is no dream. Two or three decades ago it would have been impossible, but there has been a lot of water over the dam and a lot of disease resistance bred into roses since then. Rose growers and breeders both got tired of rose gardens filled with chronic invalids. They began to feel guilty about pouring chemicals onto their roses to keep them disease free.
To stay away from summer-long spraying, you may want to try some of the newer rose varieties. There are hundreds on the market with strong disease resistance. And they include hybrid tea roses, which once seemed to be magnets for black spot. Some new hybrid teas never get black spot, even in the warmer and wetter climates where it is endemic. Nor will you need to sacrifice profuse flowering or scent to add disease resistance. Spend some time this winter looking up disease resistant roses and be prepared for a pleasant surprise in next year's rose garden.
Q: An oak tree that is very dear to me has round, brown balls stuck to the back of some of its leaves. I believe that they are called galls. What can I do about them? I would be heartbroken to lose the tree.
A: Galls are formed by trees for a variety of reasons, all protective in one way or another. Galls create bumps on leaves or twigs, brown or brightly colored. Although some galls are a response to infection, most are reactions to insects or mites. Where the insect feeds or lays eggs, the tree responds with chemicals that create the gall, isolating the insect damage from other tissues nearby.
Almost certainly the galls on your oak leaves formed where a wasp laid eggs. Neither the galls nor the wasps will damage the tree. If you consider the galls unsightly, you may be able to move the wasps elsewhere in the future. Cut off leaves with galls, so that the next generation of wasps is not produced on your oak. Clean up the dead leaves under the tree, because some insects spend the winter in leaf litter, hatching as adults in the spring.
If the galls do not bother you, ignore them. Keep the oak healthy by giving it enough water and not too much fertilizer. It takes a massive number of galls to stress a tree.
Q: Should I be cutting off the rose hips on my plants, or leaving them to look at this fall?
Q: When should I prune the roses?
A: Rose hips are the fruit of the plant, developing after the flowers are gone. Some rose growers remove all the flowers as they fade, in order to encourage new blossoms to start. That keeps hips from forming. Once rose hips exist there is no point in cutting them off. Enjoy their color in the fall landscape.
For roses that bloom once, like old garden roses, the best time to prune is right after they flower. For all roses that bloom more than once, prune just as they are making their first leaf buds in spring. These roses bloom only on new stems, never on last year's growth.
Q: Is there any kind of zucchini that isn't watery and tasteless?
A: There certainly is. I grow nothing else. Next year look for the Italian heirloom types called "Romanesco". They differ from other zucchini in having longitudinal ribs, so that in cross section they look like multi-pointed stars. Some have specific cultivar names; one I particularly like is "Latino". Romanesco zucchinis have drier flesh with a nutty flavor. They also produce fewer squash on a plant than the other types.
If you plan to grow tomatoes indoors this winter, in six-inch pots, it is already time to be starting seeds for the first pot. From seed to ripe tomato takes four months. That means that tomatoes planted now should be ready for Christmas dinner.
Master gardener Molly Hackett, whose motto is “Never trust a gardener with clean fingernails,” welcomes your questions. Send them to 1384 Meridian Road, Victor, MT 59875; call 961-4614; or email firstname.lastname@example.org. Please include a garden-related subject line in emails.