This past winter, though mild in many respects, saw some bitterly cold periods, followed by a very slow spring warm up. This same pattern occurred a few years ago as well.
The leaf buds of woody species respond to changing day length and the accumulation of warm days, or growing degree days. I am beginning to see winter’s handiwork as warm days slowly accumulate and plants finally respond. The damage is significant in a number of cases. Trees, shrubs and herbaceous perennials alike are only partially coming alive, it seems.
What to do? The first thing is, do not panic just yet. Give your prized plants a bit more time before sending them to the compost pile. The best method with struggling herbaceous plants is to divide healthy clumps of the same variety (if you have more then one), transplanting the divisions to enlarge the plant mass in the border. Woody plants, however, are a bit more tricky and require a closer examination. I would check the leaf buds first. Are they completely gone? Do they fall off easily if picked gently? Gently bend the branch. Does it snap like dry wood (because it is dry wood)? If there is still some flex, take a fingernail or pruner blade to the stem, scratching the bark to see if there is any green tissue beneath. Where there is still some juice, there might still be some hope. You might wait another month or so for any last stragglers. At that point, there might be some tough decisions to make. You may be able to prune out the dead, back to live tissue, or you might have to completely remove the plant. We have a half dead looking, large sized Japanese maple under observation for example. It might end up going the way of all plants if it does not leaf out soon.
I had a professor once tell me not to be upset if a plant dies. A dead plant is just an opportunity to plant something else. Maybe something even cooler.
Josh Steffen, Horticulture and Facilities Manager