Better to cull diseased ash trees, find out what's making them sick
HORTOSCOPE: See Page 5 Q: We have an old green ash tree. About 75 percent of the tree's branches on the north side are dead (brittle and void of leaves). The rest of the branches are healthy. It has good protection from the elements. Any ideas as...
HORTOSCOPE: See Page 5
Q: We have an old green ash tree. About 75 percent of the tree's branches on the north side are dead (brittle and void of leaves). The rest of the branches are healthy. It has good protection from the elements. Any ideas as to what to do? (e-mail reference)
A: This means that only 25 percent of the tree is alive, so it is not worth anything to consider keeping because it is not fulfilling its architectural, aesthetic or functional role in the landscape. What killed it could be determined by a lab diagnosis, so you are better off taking it out at your convenience. Bark beetles, lilac/ash borers and cankers are among some of the leading causes of ash tree decline.
Q: I frequently read your column and enjoy it, but this time I thought I'd take a moment to write you a note. I live on our family farm south of Jamestown near Nortonville. I have a tree grove that is in sad shape because it is very thin in spots. Grandpa planted it back in the late '40s when he moved here. It has what I believe are Chinese elm and plum trees. The plum trees are reasonably thick, but not the elms. All I'm interested in is wind protection, so recommending any species to plant would be greatly appreciated. I get a lot of the Chinese elm volunteering around my house, so last spring I dug some up and transplanted them in my grove, but almost none grew. The volunteers were in full leaf when I dug them up, so I wonder if I planted the trees too late. We have rich, black soil and I believe the moisture level should be adequate for most varieties. Part of the grove is in a low area, so some years there is standing water in the spring, with a heavy concentration of barnyard runoff from my beef operation. I was told willows were a good choice, but that idea didn't work. Lastly, what is the correct time of the year to prune heavier limbs on trees such as elms, cottonwoods, and also black and blue spruces? (e-mail reference)
A: Thank you for writing and being a loyal reader! I need to make a quick correction to begin with. What you and most everyone else call Chinese elms are Siberian elms. The true Chinese elm is a beautiful, stately, small tree that is not hardy to our area. Chinese elm has beautiful, exfoliating bark as it matures and, unlike other elms, flowers in the fall. The Siberian elm is fast-growing, weedy, inhabited by insects, ravaged by diseases and extremely sensitive to herbicide drift. The only saving grace it may have is the fast growth. To transplant volunteer seedlings, you need to dig them up while they are dormant and plant as soon as possible. The seedlings need to be planted at the same depth as before. Ash trees have been recommended in the past, but now have become overplanted and with emerald ash borer breathing down our necks in a few years, I have to put a hold on recommending planting ash at this point. American elms, black locust and poplar species are suitable for your situation. The willows may have died because of the soil salts being too high. You might want to get the soil tested in the problem area. As for major pruning, now would be a good time to start, at least on the deciduous trees. There are no insect or disease problems right now and the branches are visible for good pruning cuts, but wait until the weather turns a little milder. For evergreens, I would suggest waiting to prune until just before new growth emerges in the spring.