Those ugly black lumps on your cherry, plum or chokecherry are black knot, a fungal disease that spreads through Edmonton yards. Here is how to spot it, what it does, and how to deal with it before it kills the tree.
Black knot is a fungal disease that forms hard, black, swollen growths on the branches of cherry, plum and chokecherry trees. It is very common in Edmonton and, left untreated, it spreads and eventually kills the tree.
It spreads by spores in spring, infecting new growth. The knots take a year or two to appear, then swell and multiply. Popular Edmonton trees like mayday, schubert chokecherry and ornamental plums are especially prone.
Hard, black, warty lumps that wrap around twigs and branches.
New infections start as soft olive-green swellings.
Knots twist and girdle the branches they grow on.
More knots appear season after season if untreated.
Mayday, chokecherry, plum and cherry are most at risk.
Growth beyond bad knots weakens and dies.
Black knot only gets worse on its own. Here is why to deal with it now.
Every job is planned and led to International Society of Arboriculture standards.
Proper gear, rigging and property protection so nothing gets damaged.
We haul away all wood, branches and chips and leave your yard clean.
A clear on-site estimate with no surprises. What we quote is what you pay.
A free on-site visit to see the tree, the access and the drop zone.
A clear, no-obligation quote. What we quote is what you pay.
Certified, careful work with the right gear for your site.
Every branch and chip hauled away, the area left tidy.
The only real fix is to prune out every infected section, well below each knot, in the dormant season.
There is no spray that cures black knot. It is removed by pruning out the infected wood, cutting several inches below each knot, in late winter while the tree is dormant so spores do not spread. The cut wood must be destroyed, never left in the yard. If the disease has spread through most of the tree, removal is often the wiser choice. Our arborists can prune it out or, where needed, remove the tree. See our black knot removal service.
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