Rose rosette disease not common

Q: We have Knock Out roses in our subdivision landscape and are planning to add more. We have heard that a virus is beginning to attack roses. Should we be concerned about this to the extent that we not add any more? George Kesler, Hoschton A: If the roses look healthy, there is no need to substitute other plants. Rose rosette disease is transmitted by mites, not by contaminated soil or water. If you don’t have infected plants in the vicinity, any new roses you add will grow fine. However, examine any new roses for excess thorni- ness and a distinct reddish cast to the stems. These two symptoms are common on rosette infected plants. Q: A tree service company has cut down a tree infested with pine beetles on a next-door neighbor’s property. What should I do if they don’t remove the cut logs from the area? Gordon McCulloh, DeKalb County A: Talk to your neighbor and ask that the logs be fully covered by a plastic tarp with the edges completely sealed with soil. Leave the tarp in place for thirty days. The heat under the tarp will kill most beetles and their eggs. For details on pine beetle detection and control, see xrl.us/pinebeetles. Q: I mow my zoysia lawn every two weeks but the blade rips the grass out, even though it’s sharp. I had to adjust the mower height up because the grass is so thick that my mower stalls every few feet when I cut. Eric Thompson, Flowery Branch A: If your mower is stalling, you aren’t mowing often enough. The mower blade is hitting tough stems instead of tender grass blades. Zoysiagrass has a lot of silicon in its cells, making it tough on blades. In addition, it looks reasonably level even when allowed to grow for two weeks, fooling you into delaying mowing. Zoysia should be mowed to a height of 1.5 inches. That means you should mow when the grass reaches two inches high, whether it looks like it needs mowing or not. Lower your mower height one notch now and mow every week. Mow at the correct height next spring. Q: What type of privacy shrubs would you recommend to plant on the Georgia Power easement part of my property? I need plants that grow no more than fifteen feet high. Roger Borkowsky, email A: I recommend ’Emerald Green’ arborvitae and ’Nellie Stevens’ holly. The holly can grow a bit taller than you want but it can be pruned once every few years to keep it in bounds. I have a list of more screening plants for different situations at xrl.us/screening Q: I planted a root from a piece of ginger that I had purchased. The plant is in a small pot and is doing well. How will I know when to harvest it? Nilam Parekh, email A: If your potted ginger is indoors, I doubt that it has enough roots to make an entree. Ginger likes to grow in full sunshine and will reward you with many thick roots if it’s placed there. To check my prediction, simply pull the plant out of your pot and check the roots. If there is something to harvest, several thick white rhizomes should be running around the interior of the pot. Since ginger is sometimes not winter-hardy, keep it indoors for winter, but take the pot outdoors in April.