Congratulations! We just survived one of the coldest winters in recent history. Spring has finally arrived, even here at 7,000 feet. Bulbs are blooming, trees are budding, and there’s a bit of green in the dead grass. As my perennials finally begin to sprout, I’ve been busy clearing off the dead stems and dried seed heads. One by one, they return to life, and I mentally take attendance. Catmint? Here! Blue Mist Spirea? Here! Ornamental Sage? Hello? Has anyone seen Sage lately?
Yes, some of my favorite plants are no-shows. Others, such as the Blue Mist Spirea, are producing leaves from the base of the plant, but the stems are still bare and lifeless. As I check on the woody plants in my garden, I notice that not all my shrubs are leafing out as expected. Should I cut them down? Dig them out? Or am I just too impatient? How can I tell if there’s still life left in those limbs?
When it comes to perennials, especially those that completely disappear during the winter, it’s just a matter of waiting. If you’ve had the plants for a while, you probably know when they normally start to sprout. If several weeks pass and there’s no sign of growth, it’s time to dig them out and replace them.
Woody plants are a bit trickier. We don’t want to kill a plant that’s just being cautious about breaking dormancy, but we also want to remove it if it’s beyond hope. The simplest way to check if a small branch is still living is to use your fingernail to scratch a bit of bark. Is it green underneath? Is the branch somewhat flexible? Or is the wood brittle and gray-brown all the way through?
In some cases, such as with my Blue Mist Spirea, the roots may be alive but the above-ground plant has succumbed to the cold. In those cases, you can often prune the plant all the way down to the ground. This works best on fast-growing plants that put up multiple stems from the base, such as Butterfly Bush and Forsythia. You can even check each branch before pruning to make sure it’s actually dead—sometimes the outer branches shelter the ones in the middle.
When pruning other woody shrubs, cut the stems back to where they’re green. After you’ve removed the dead wood, you can go ahead and prune to remove branches that are crossed or heading in the wrong direction. To maintain a more natural look, trim back to a side branch that you want to encourage, or remove the entire branch back to where it starts.
If you’re removing a large branch, be sure to leave the “collar” where it joins the trunk. This tissue will allow the plant to heal. Don’t paint the cut wood with any tar or other seal—it isn’t necessary and may actually cause the problems you’re trying to prevent.
If the cold winter has left holes in your landscape, you’ll want to fill them with new plants. Should you replace them with the same variety, or choose something new?
According to the USDA and my own garden records, I’m in the colder half of zone 5. If I’m buying an inexpensive perennial or fast-growing shrub, I’ll go ahead and purchase plants hardy to zone 5—or even zone 6. However, if I’m investing in a tree, or a fancy cultivar that costs quite a bit, I’m more conservative. You never know when that 100-year cold snap will hit. In that case, my choice needs to be sturdy enough to survive a zone 4 winter.
So, choosing a replacement plant is really up to you and your budget. If the dead plant is one of your favorites, and you can afford to buy a new one every so often, go ahead and splurge. But if all you want is “something green” next to the house, I’d swap out something hardier. They say the climate is getting warmer, but weather in Colorado has a mind of its own!