Thursday, March 13, 2008
Prune yews with care; seed grass at your own risk
John Arbogast
Landscape consultant John Arbogast answers your questions every Thursday. Send questions about your lawn, garden, plants, or insects to:
Dear John
5102 Greenfield St. SW
Roanoke, Va. 24018
Or send an e-mail. Answers will be given only in this column. Please don't send pictures or samples.
Recent columns
Q: I have a question about the name of a shrub and pruning it this spring. This is a fairly big evergreen shrub. We have several of them in our Virginia landscape in the yard of the house that we purchased. This shrub has dark green needles and they are darker than the other evergreens in this neighborhood. The average size of the shrub is about 4 feet tall and 6 to 7 feet across. The needles are flatter than pine needles and are about 1 ½ to 2 inches long. A friend called these taxis bushes. Can we cut them way back? A neighbor said that the previous owner planted these shrubs back in the early '80s. How much can be pruned off? When is the best time to do this?
A: Your shrubs sound like the plant whose botanical “genus” name is Taxus that are commonly called yews. You might have the variety called ‘Densiformis,’ which describes their dense branching and rather large size.
No, cutting any needle evergreen way back is not recommended. Practically all needle evergreens have the biological trait of maintaining living buds capable of producing new growth only on the younger branch portions where greenery currently grows. This trait makes needle evergreens different from leafy evergreens. Leafy evergreens maintain living buds on older living branches and trunks, meaning that those plants can be cut way back to stimulate those old buds into growth.
Yews are the only “semi” exception to the “no-living old buds” rule of needle evergreens. “Semi” exception means that yews can be cut back into older branches or trunks but that new shoot emergence from old buds will take years and new growth produced will likely be thin and not attractive.
You have a choice regarding pruning your yews. Trim them only lightly and remove some of the outer greenery, but don’t shear so heavily as to remove the oldest needles. This trimming won’t drastically reduce the size of your brushes.
You can prune back into older parts and then live with ugly plants with little greenery for the next few years. Or cut them down and replace them with new, shorter plants that are appropriate for the spaces in your landscape.
Early to mid-spring prior to the expected arrival of hot weather is the suggested time for this pruning in Virginia to take advantage of the natural time of bud opening and new shoot emergence.
Q: You’ve covered grass topics before. My spouse wants me to fertilize our fescue lawn this spring here in western Virginia. I like to fertilize in the fall. Also, we have grass seeding work that needs to be done this spring. You’ve said that late summer or early fall is the best time for grass seeding to be successful in the Roanoke area. Please give your thoughts.
A: Applying nitrogen and other fertilizer nutrients to fescue lawns in the spring in this area can be a good idea as long as the amount of nitrogen provided at one time does not make the grass too lush going into hot weather. You don't want to force all the grass’s energy and sugars to be used up too soon by rapid blade growth. Accommodate these limitations by checking the turf fertilizer bag label to be sure that a significant portion of nitrogen is in a slow release form. make the spring turf fertilizer application after the normal early and mid-spring period of fast grass growth. In Roanoke, a good time for spring bluegrass and/or fescue fertilization is in early to mid-May.
Grass seeding in the spring in the Roanoke area can be a gamble. You never can predict how hot and stressful the coming summer will be, which will limit the survivability of newly formed grass roots. However, watering two or three times per week in spring and summer can help new grass plants survive. Thus, late March or early April is the second best time of the year in Roanoke to establish grass from seed.
Set up spring grass seeding for success by using quality seed that isn't the least expensive on the shelf. Do an excellent job of preparing a seed bed. Then be diligent about post-seeding care.
I’d suggest going ahead with any seeding that needs to be done this spring but be prepared to water during spring and summer. Be prepared to re-seed any spots that don’t survive summer stresses.
