OCTOBER
2010

 

 

 

By
B. Rosie Lerner
 
Purdue
Extension
Consumer Horticulturist

 

 

 

 

 

10-07-10

Question and Answer


Q. I live on a wooded lot in Wheatfield. The last 10 years or so have been hard on our Red Oaks, some of which are surely over 100 years old. The problem is that some are perfectly normal one year and dying the next. They green up normally, drop their leaves prematurely and never come back. Is there anything that can be done? Some are extremely large and others smaller. I'm worried that in a few years, there will be no more trees left.

A. There are a number of diseases, insect pests and environmental stresses, or perhaps a combination of factors, that could be the culprit. Once a tree is under stress, other opportunistic organisms can move in. Oak wilt, oak decline and borers are just a few possibilities. And there are quite a number of disorders -- sometimes referred to as "people pressure" -- that can cause trees to decline: planting too deep or too shallow and girdling of the trunk by roots, twine or wire, etc. If you have a tree that is currently presenting symptoms, you might consider submitting a sample to the Purdue Plant & Pest Diagnostic Lab (PPDL) and/or consulting with the agriculture educator in the Purdue Extension office in your county. You'll find more information on the PPDL at www.ppdl.purdue.edu and your local Purdue Extension office at www.ag.purdue.edu/extension/Pages/Counties.aspx.

Q. My husband and I read with great interest your reply to the question regarding the white pine and the fact that they are not very adapted to the Indiana climate. We started with 12 in the year of 2000. They have been replaced several times and now, based on their height, only five of the original group are left. We just lost two more that now need to be replaced. Please suggest another tree that would blend with the 10 still living.

A. While no species is 100 percent trouble-free, some of the spruce and fir species are less problematic than most pines. You'll need to assess your planting site and match as best you can a species that will adapt. If the site is plagued by poor soil drainage, it is unlikely that any evergreen species will do well, except perhaps bald cypress (Taxodium distichum); however, it drops all of its needles each winter, so would not be evergreen. But if it is an average site, some of the following species might be considered.

White Spruce (Picea glauca)
Norway Spruce (Picea abies)
Colorado Spruce (Picea pungens)
Douglas Fir (Pseudotsuga menziesii)
Fir, White (Abies concolor)
Hemlock, Canada (Tsuga Canadensis)

unusual tree trunk

Q. I had a yellow delicious apple tree die this spring. It had a bulge in the trunk, like the one in the attached photo. What is this? Is there anything I can do to stop it or prevent it in my other trees? I am concerned that I will lose all my trees.

A. That is an unusual trunk! Unfortunately, I can’t be certain as to what killed the tree from just the appearance of the trunk. But it does look like a large graft union where several scions were grafted to a common trunk, sometimes sold as three-in-one or five-in-one trees. Because many fruit trees require more than one cultivar to provide pollination for fruit production, one strategy was to graft two or more cultivars onto a rootstock.   Unfortunately, the graft union of those multi-cultivar trees is often weak-wooded and prone to dieback. If that's the case, there's no need to worry about the problem "spreading" to other trees. But most fruit trees are prone to quite a number of disease and insect problems, so it is still wise to keep the trees under close observation and if you notice any symptoms, contact your local office of Purdue Extension for diagnostic assistance www.ag.purdue.edu/extension/Pages/Counties.aspx.

 

Writer: B. Rosie Lerner
Editor: Olivia Maddox,