We have irises in our yard. Last year we noticed that they weren't blooming a lot. There were a lot of leaves, but not many flowers. So we divided them and then we replanted all of them. Once again, we didn't get many flowers this spring.
We can't figure out why this happened and what to do. They are in an area where they get plenty of sunlight and we know you're supposed to leave the bulbs partly above ground, which we do. Please help us figure out this mystery and what to do about it. -- Mandy Lavriha, Avon Lake
Happily, you are doing everything right. Bearded irises often bloom sparsely the year after planting. Many trees and shrubs are the same way; they put their energy into establishing roots, rather than flowers. They will probably bloom gloriously next year -- and for several years, until you have to repeat the process again.
My purple coneflowers (echinacea) have bloomed every year, but this year they appear to be dying. When the plants reached about three-quarters of their full height, around the beginning of June, they began to droop downward. The stems became curly, almost vine-like, and have purple coloring on them. They didn't bud, and I am afraid I will lose them all.
Any suggestions as to what may have caused this, and is there a remedy? -- Linda Evers, Garfield Heights
This is a tough question, impossible to fully diagnose without a sample or even a photo. But after conferring with several experts, I feel my initial hunch is accurate.
These cone flowers may be dying, but probably from weed killer rather than from pests or disease. Was herbicide applied in the vicinity in late May -- perhaps "weed and feed" on the lawn nearby?
While twisting, purple stems are not typical symptoms of purple coneflower diseases or pest infestations, they can be a sign of herbicide damage. In certain weather conditions, weed killers can drift far across a lawn and affect plants they were not intended for.
Arie Blom, an acclaimed European echinacea breeder, concurs: "[You] could be right. Systemic herbicides like glyfosate, 2,4-D, MCPA, etc. let the plants grow themselves to death. The plants do not grow straight, but curly. The herbicide is transported from the leaves to the very end of the root tips, so the plant will be killed completely. When you think the herbicide has drifted towards your border plants, you better cut the plants down to the ground and hope they will re-grow.
"The purple coloration is probably a stress reaction. The plants of that size (¾ of full size) is not killed instantly. It can take up to two weeks; in that period the plant can make anthocyanins, chemicals that act as anti-oxidants. But that cannot prevent the plant from dying.
"I would advise her not to plant echinacea in the same spot. I prefer not to plant the same crop in the same spot, even if the old plant was healthy enough."
What do you use to change the color of a hydrangea bush? -- Beverly, Garfield Heights
While many hydrangeas bloom white, Hydrangea macrophylla, the bigleaf hydrangea, usually has mophead flowers of pink or blue, depending on the pH of the soil. Add lime for pink blooms. For blue flowers, lower soil pH below 6 by adding aluminum sulfate (applied per directions).
This takes time, and is challenging in high pH soils. Avoid high phosphorus fertilizers. Start by testing your soil, following these directions (pdf). Our OSU extension and their Ohioline factsheets offer a wealth of information.
You can also purchase hydrangea cultivars that tend toward pink or blue. In our 6.5 pH garden, Hydrangea m. 'Glowing Embers' blooms rosy red, while its close relative, 'Blue Billows', has blue lace-cap flowers. Other bigleaf hydrangeas have blue and pink blooms on the same plant.
For reliable bloom in Ohio, look for cold tolerant cultivars -- especially those like 'Endless Summer' that bloom on old and new wood. The "wrong color" is better than no bloom at all!