Fielding questions: Winter snow damage to trees and shrubs, hoya houseplant flowering
In this week's Fielding Questions, Don Kinzler answers questions about losing branches due to recent wet, heavy snow accumulation.
Q: I’ve been out removing snow from my Skyrocket junipers and a vulnerable spruce, but I never dreamed a bare lilac tree would be the first casualty. - Matt E.
A: Anyone who shoveled or used a snowblower in the region’s recent wet, heavy, deep snow can attest to its weight. Snow is great insulation for plants, but when the layer is sticky and thick, damage quickly mounts, especially on evergreens or other trees and shrubs whose branches trap snow.
Like you, I am surprised that your lilac tree was the first to snap under the pressure. Lilac trees do have dense, closely spaced branches though, which probably contributed to snow buildup.
If I’m looking at the photo accurately, the branch section that broke might be expendable. Prune the broken section cleanly back to an intersecting branch. When such breaks occur, there isn’t a successful way to splice parts back together.
Although pruning out the broken part might leave a temporary imbalance, future growth usually fills in the gap on these lilac trees, unless a large chunk is missing.
Q: A six-inch diameter branch snapped on our 25-foot-tall juniper about 15 feet up because of heavy snow. Our 15-foot-tall Ponderosa pine is bent over with its top about two feet off the ground and resting on a snowbank. We can’t even see our 10-foot-tall cedar, which is just a pyramid of white snow. I tried to knock snow off the trees, but it is iced on. Damage is really bad here in southern North Dakota. Repairing evergreen injuries would be a good program topic. – Lyle T.
A: Over 25 inches of wet, heavy snow hit parts of the Upper Midwest, including your area. Deep snow that’s fluffy is much less problematic, but the recent wet snow stuck to everything. Followed by cold temperatures, it turned to blocks of ice, as you found.
What should we do when snow weighs heavily on branches, close to the point of breakage? Caution is needed, because removing snow itself can cause branch breakage, especially in cold temperatures, when evergreen branches are more brittle.
Sometimes there’s little that can be done. Shaking trees or shrubs to remove snow isn’t recommended. To remove snow from an evergreen, begin at the bottom, because starting at the top will cause additional snow to fall on lower branches already heavily laden. Gently brush away snow, supporting branches with one hand while sweeping snow with the other.
When snow has frozen onto branches, removing is difficult. If evergreens are bent, but not broken, they’ll often recover without special care. Branches obviously cracked or broken can be pruned away now, with additional shaping or pruning in spring. Creative support can sometimes be given to branches that are sagging, but still intact.
Wet, heavy snowfalls can be an evergreen’s worst enemy, and sometimes there’s little we can do.
Q: My hoya houseplant is finally flowering, and I’ve had it for eight or 10 years. The flowers are along a long, vining stem. When it’s done flowering, do you cut off the flowering stem, or leave it? – Brenda S.
A: Hoya, also known as wax plant or porcelain flower, is a vining native of tropical rain forests, where it scrambles up trees. The star-shaped flowers are borne in clusters, and patience is a must, because hoya waits for a certain stage of maturity before blooming, often five to 10 years when grown as a houseplant.
Flower buds form on stems called spurs. These spurs flower year after year, given the right conditions, so these flowering stems should be left intact, rather than removing to ensure your plant continues flowering.