Q. I need to replace some trees along my driveway. The driveway is bounded by a three-foot-wide median, and my neighbor's drive is on the other side. I had Bradford pears, which were a disaster. They break easily and deposit fruit that weld themselves to a car's finish. I cannot use the driveway for two months a year. What would you recommend that would fit the space and not leave a mess? A. You need a tree that is narrow and upright so it doesn't interfere with vehicles in either drive. Red Rocket red maple would fit the bill, or you might consider the seven sons flower, which is often considered a shrub. It is easily trained to a single trunk and provides lovely fragrant flowers in late summer when nothing else is in bloom. The botanical name is Heptacodium miconioides. Q. Deer ate the new shoots of my azaleas and rhododendrons. Should I prune the bare stems, or will they come back? A. There is no need to prune your azaleas and rhododendrons to remove deer-damaged foliage. Unfortunately, deer are creatures of habit, and it is very likely that they will graze on your shrubs again. You may try spraying deer repellent on the plants to protect the new growth, but keep in mind that repellents work best when applied frequently and where the deer population is not really high. You can protect each shrub with deer netting, but the results are less than attractive. A perimeter electrified wire fence baited with peanut butter or a tall fence constructed of deer netting might be the most effective and least aesthetically offensive solutions. If you are trying to protect a single plant, you can use a system called Wireless Deer Fence (www.wirelessdeerfence.com), in which baited electrified posts are set around the plant. Deer populations are indeed unchecked in some regions. Aside from the threat to automobile traffic, they are a reservoir for ticks that can spread disease. In addition, the deer have eliminated much of the native vegetation in many tracts of woodland and in some cases are preventing the regeneration of native tree species. Invasive nonnative plants can colonize woodland in which native vegetation has been eliminated more easily than intact woodland. Scott Aker is a horticulturist at the U.S. National Arboretum. 