Q. I need to know when to trim clematis. I have tried for 10 years to grow them. I now have three growing. One is so tall, and I want to know how to keep it full and blooming. &emdash; Veneda Hoesel, Winamac, Ind.
A. If you categorize clematis by their pruning needs, there are three different groups. Group one blooms in the spring on last year’s new wood. Little pruning is needed except for shaping, and they should be pruned immediately after flowering. Group two blooms in early summer and includes many of the large-flowered and double-flowered cultivars. Shape or thin in early spring, cutting the vines back six or eight inches to a pair of strong buds. Group three blooms in late summer or fall on this year’s growth. These plants should be pruned to new shoots coming from the ground or to strong buds on old wood in early spring. This group includes the common ‘Jackman’ clematis. Basically, groups one and two require little attention, but group three requires pruning each year for ideal flower production.
Q. I have a clematis that is over 40 years old. The last few years, I’ve noticed the leaves are a very pale green. I’ve used Miracle Grow on it, and it has lots of pretty flowers on it. What should I use to help the leaves to be a dark green like they used to be?&emdash;Florence Childers, Bedford, Ind.
A. Clematis like a thick layer of mulch and regular fertilization. A few inches of well-rotted manure and a handful of 5-10-10 in early spring should be applied each spring.
Q. I have a clematis that sets lots of blooms, but they never open. It grows well. It has healthy-looking leaves. When I’ve pruned it in the past, it grows back nicely, sets blooms, then that’s it. They never open. &emdash; Dan Couch.
A. The fact that it’s setting buds means you’re pruning at the right time. The unopened buds could be due to botrytis blight, thrips or cold injury. Cold injury would only happen in years with a late cold snap. Thrips are small insects that feed on the soft plant tissue, causing the buds to turn brown and die before opening. Thrips can be controlled with isotox or orthene and good garden sanitation. Botrytis blight is also called blossom blight or bud and flower blight. To reduce blight, keep dead leaves and flowers picked up, keep foliage dry and consider spraying with a fungicide. Before choosing a treatment, however, you must identify the problem. Next spring, take some of the unopened buds to your county Extension office for problem identification.
Q. We have a wonderful asparagus patch. The problem is bug eggs. Even when we pick it every three days, there is a little multicolored beetle-type bug that eats on it and lays eggs on the stalk. Once, we quit picking. We can dust with Sevin dust but what can we do while it is still the picking season? I could deal with the bug itself but hate the eggs it lays. Would it help to just sprinkle the Sevin dust on the ground so that the bug would have to crawl through it to get to the stalk? Thanks. &emdash; Betty Stinemetz Winamac, Ind.
A. Asparagus beetles can fly onto the plant, so dusting the ground will not exclude the adults from the plant. This fall, remove all the dead foliage and mulch from the area and apply new mulch. This will remove most of the overwintering insects. In spring, cover the patch with a lightweight floating row cover. It’s a sheer blanket&emdash;available from many of the mailorder garden catalogs&emdash;that keeps the beetles from landing on your plants. If you still have a large adult population, you can spray with carbaryl (Sevin) or rotenone but follow the directions carefully concerning harvest and consumption of the spears.
Q. I have a blackberry bush that has grown a stalk that is wide and fat. It has no leaves, no blossoms. I am thinking it should be cut at ground level. Am I right or wrong? &emdash; Mary Haiflich, Ossian, Ind.
A. Each spring, you should remove all weak, diseased and insect-damaged canes including the one you described. Also, remove all canes less than one-half inch in diameter, and remove all but three of the largest canes.
Q. Are white mulberries (all fruit on one tree) very common? I’ve seen two so far in my town. Please let me know if I have something rare or not. &emdash; Brian Knisley, Syracuse, Ind.
A. White mulberry (Morus alba) is a common tree in Indiana. It is a beneficial tree to birds, and it tolerates dry soil. It is not particularly desirable as a landscape tree, since the birds and fruit can make a mess below. The foliage is somewhat dull, and the roots can damage pavement and sidewalks.I grew up with large mulberry trees in our backyard. Not only were they attractive to legions of birds but also to two beautiful foxes.