Snow White Black Knot
I planted a multi-stemmed Canada red chokecherry (Prunus virginiana 'Shubert') years ago in my landscaping so I could admire the deep, purplish-red foliage; a signature display of this selection. Of course, that was before anyone knew it’s a magnet for the fungus, Apiosporina morbosa; the plant pathogen that causes black knot. The disease is characterized by thick, corky, elongated gall-growths on twigs and branches that become coal-black late in the growing season; thus the common name for the disease. Black knot is now the signature display of many Canada red...