| Beverly Shaw
Question and Answer
Q. I have four large trees in my backyard, causing quite a bit of shade.
There is a pine, an oak, ask an and a maple. The lawn is too dark for
grass, and the quantity of leaves is overwhelming in the fall. I'd like
to take down one tree but can't decide which one. I don't feel particularly
attached to any, although the pine screens the neighbor's yard somewhat.
All seem to be roughly equal in size and health. Any thoughts? -- Janice
Laskey, West Lafayette, Ind.
A. Any other year, this question would be difficult to answer definitively.
However, a new threat to ash trees is bearing down on our borders. The
emerald ash borer has killed over 6 million ash trees in the Detroit-area
alone. Although quarantines are in place to slow its progress, this pest
has already reached our border with Ohio. Our ash trees are threatened,
and no good chemical treatment has proven effective yet. Many municipalities
and entomologists are recommending no ash trees be planted in the near
future, but instead, any new plantings should work to increase the diversity
of our forests and landscapes. Given that the ash may be attacked and
killed by the emerald ash borer, and the other trees are healthy and desirable
species, I would remove the ash. For more information, go to http://www.ppdl.purdue.edu/PPDL/.
If you decide to keep the ash for some reason, you can lessen the likelihood
of attack slightly by keeping the tree free of stress. This means providing
water during dry periods and fertilizing to maintain health and vigor.
Borers tend to attack trees already under stress. Unfortunately, the emerald
ash borer seems to be less particular about a tree's well-being than other
ash borers, and will eventually work its way to non-stressed trees, too.
This is bad news for all Indiana gardeners. It is a good time to add
other species to your landscape!
Q. My Siberian irises are filled with ants in the ground around the
stems. Are ants pests of Siberian iris? Or are they not a problem? Thanks.
-- Cheryl Kolb, Lafayette, Ind.
A. Siberian iris and ants are not a common pairing, It's probably coincidental
that the ants are making their home in your irises. If there is some distance
between the ants and the plants, they don't need to be treated, but it
sounds as if they're interacting more directly than that. If the ants
are actually in the rootzone, treatment may be necessary. Ant tunnels
provide a means for cold, winter air to get down to the iris roots and
this could damage or kill the plants. If this is the case, treat with
an appropriate insecticide following label directions carefully.