QuestionI live in Seattle, Wa. Can you tell my why my rudebekia plants did not flower this year? It was their 3rd year and of 3 plants only 1 had 1 flower. The foliage seems to be happy and spreading. No powdery mildew or anything else obvious going on. Other plants nearby seem fine: lavender, huchera, asters, echinacea, a Japanese maple.
Thanks! Flo
AnswerCould be any of several possible problems. My favorite answer this week is to point a finger at allelopathic plants -- which secrete chemicals that are toxic to potential predators and others as a way of avoiding competition. But they don't affect ALL plants.
Maple leaves for instance are receiving attention for a chemical they produce that kills Weeds -- but not Grass. So you can see that the Japanese Maple you mention is a signal here that you might have a potential problem.
Lavender and Echinacea too can make life difficult for plants on its hit list. Phenolics, Flavonoids, Alkaloids, Saponins and Coumarins may also battle disease causing microbes or plant-eating animals. Simple compounds can turn Allelopathic when released into Soil.
However, this is the first year you have had trouble, and there is a 2 year history in previous seasons of obtaining some perfectly splendid flowers out of these plants that are now declared duds. That does not point to Allelopathy.
Rudbeckia fulgida var. sullivantii 'Goldsturm' was the Perennial Plant of the Year in 1999. This is a plant with a solid reputation it has earned. I don't blame you for being disappointed in it.
The Pacific Sun website posts its own advice on perennial care:
www.pacificsun.com/story.php?story_id=2252
They write, 'Rudbeckia can be divided every three years in early spring to maintain vigor. Many Black-eyed Susans will only live for a year to three years, so it's best to grow often from seed.'
That's right. It's possible the life of your Rudbeckia collection has been too easy. Now they're kaput or on their way there. Divide and conquer. Need instructions?
THE LONG ISLAND GARDENER
