Q:Three years ago I purchased several dogwood trees from a discount store. They were 5 feet tall and cheap. They have grown beautifully, but not a single bloom. Friends have purchased more expensive dogwood trees from garden stores and the first year they were laden with blooms in April. Are mine ever going to bloom, and is there anything I can do to make them bloom?

Answer: While I always recommend buying plants from a good garden center, I don't think the source of your dogwoods is the problem. The fact that they have grown "beautifully" and acclimated to your yard is a good sign.

When plants grow too well they often are slow to make blooms. Nitrogen makes them produce lots of foliage at the expense of flowers. Keep any fertilizer away from your dogwoods for a couple of seasons, particularly lawn fertilizer. Once their vegetative growth slows down, they should get into a normal blooming cycle.

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Q:I have white clover in my yard that I would like to identify. It spreads by runners and after you mow it will rebloom in four to five days. Honeybees seem to love it. I have several hives and I would like to identify the clover so I can plant it someplace other than my yard.

 

Answer: It may be impossible to identify the exact variety of white clover you have. However, it's probably common white clover. Clover is a legume that has the ability to fix nitrogen in the soil and actually help feed the fescue. For years, prior to the late'80s, we recommended 10 percent white clover in lawn mixes with 90 percent fescue.

Ladino clover is a white clover that is used in pasture mixes and grows taller than the common white clover that often shows up in lawns. You might want to visit your nearest farm supply store and see which varieties they carry.

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Q:I think I have killed my roses. In years past, my roses have been heavily damaged with yellowing leaves and black spots. The salesman at the garden center advised me to make a mixture of a fungicide, horticultural oil and water. This worked well for several summers.

 

This summer I mixed a new batch to spray the roses. Within a few days they began to wilt and leaves curled and turned brown. I notice that stems are also brown.

I couldn't remember the exact formula and I'm afraid I used too much of one of the items and perhaps not enough water. I pruned the roses and have been giving them lots of water. What do you suggest?

Answer: Your experience helps to demonstrate the importance of following the label anytime you use pesticides. Many products are compatible. However, it's critical that you use the rates recommended by the manufacturer.

Without seeing your roses, I can't really predict how they will recover. However, roses are amazingly tough. With adequate watering, following the pruning you already did, if they are going to recover you should start to see new growth pretty quickly.

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Q:I have two very old and healthy English boxwoods that have never been pruned. Unfortunately, they are beginning to look oversized for their surroundings. How do you trim these back, and what time of year is best to do this?

 

Answer: English boxwood grow very slowly, as I'm sure you realize. Consequently, they cannot be pruned back too severely. The ideal way to trim them is to thin from inside the plant. This will leave small openings that allow sunlight to get inside, which will stimulate new growth from within.

The ideal time to prune them is late February or early March before they start producing new growth. Pruning old English boxwood is somewhat of an art and there are companies that specialize in providing this service.

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Q:We recently built our retirement home and have quite a bit of landscaping to do. We live in South Boston now but lived in Richmond for 10 years. Would you please recommend deciduous shrubs to plant to screen our heat pumps? They receive full afternoon sun.

 

Answer: Heat pumps generally run around 3 feet tall. Most deciduous plants would grow much taller and wider. You might consider Japanese barberry, Berberis thunbergii. I particularly like the cultivars Concorde and Crimson Pygmy. Both get about 2 feet tall and 3 feet wide. Rose Glow is a cultivar that grows to about 5 to 6 feet tall. All three have maroon-colored foliage. Richard Nunnally is a freelance writer and speaker as well as host of WCVE's monthly gardening show, "Virginia Home Grown." Questions can be sent to tdgarden@comcast.net or P.O. Box 3690, Chester, VA 23831.