Only the Hardiest Shall Survive!

What made it through this winter? I know many of us barely did, but now that spring has seemingly sprung into summer my concern turns to the landscape. Here in west central Illinois we live in USDA cold hardiness zone 5b, with an average annual extreme minimum temperature of -10 to -15 degrees Fahrenheit. However, this winter we saw temperatures dip below the -20 degree mark, granting us a zone 5a or in some locations a zone 4 winter.

As the weather warmed, I emerged to asses my landscape plants, taking note of who made it and who did not. Several small seedling trees, willows, a magnolia, and a hydrangea have failed to leaf out this year. The tree of most concern for me is a 40 foot tall sweetgum in my front yard. The droughts have not been kind to this tree, and the winter was just as brutal. Sweetgums are only hardy to zone 5 and mine still has yet to leaf out completely as of the first week of June. I have noticed a significant amount of dead limbs in the canopy this spring. Make sure if you are experiencing similar dieback in your larger shade trees, contact a certified arborist to assess and remove the rotting limbs.

My crape myrtle, which I have been cheating the odds with these past few winters, sadly appears to have met its maker. Hardy only to zone 6, a crape myrtle in zone 5 behaves more like a rose bush as it experiences some winter injury which is easy to prune off and then puts on a great show all season. Another item crape myrtle and rose have in common, is the Japanese beetles finds both very appetizing.

Speaking of Japanese beetles, Extension entomologist Phil Nixon believes the depth to which the ground froze last winter was deep enough to kill some Japanese beetle grubs. Therefore, we should see a decreased number of these pesky beetles this summer. There is good news after all!

For the past two months I have been receiving calls regarding what to do about desiccation or winter injury to landscape plants, namely evergreens. There is always the potential for evergreens to green back up and grow out of the desiccated foliage. However, if the winter damage in your evergreens hasn't greened back up by now, then it is time to prune out the damaged foliage. Larger evergreens that have seen considerable damage such as losing an entire side to winter injury may need to simply be replaced.

I have also received a few calls from homeowners and commercial landscapers in the Galesburg area experiencing large areas of dead lawn. At first, I suspected snow mold but these were in wide open locations that did not receive the excessive piles of snow that say an area adjacent to a road or sidewalk might. After some investigation it appears the culprit is the same as what hit the evergreens, desiccation. Desiccation is when the plant continues to lose water through the leaves, but cannot take up water due to the ground being frozen.

Moral of the story: this summer we need to be kind to our trees and shrubs. Water them if we do not receive adequate rainfall. Mulch appropriately - 2 to 4 inches deep and keep the mulch away from trunks and stems. If you can, opt for compost mulch to provide your soil with some organic matter and a trickle of nutrients. Rake out or till up any dead lawn patches and reseed. Establishing lawn seed is always more successful in the late summer to early fall.

What didn't make it in your landscape? Please post your comments below.