Q: Our sedum is on the south side of the house, and it's always done well. This year, there were no blooms, and it doesn't look healthy. It gets adequate watering, the same as other years. Any help you can offer would be appreciated. -- Mary K.
A: Upright sedums are among the most colorful fall perennials. Autumn Joy and other cultivars begin blooming in September and are sometimes still blooming during the first snowfall.
Two factors probably affected your sedum's poor performance this year, Mary. Our long stretch of unusually hot September weather wasn't the preferred weather for the development of fall color, including flower formation on sedums.
Fall-blooming perennials are accustomed to cooler temperatures, and extended periods of heat can throw them off balance. Our own sedum didn't bloom as colorfully as in years past.
We're at the mercy of Mother Nature for temperatures more conducive to better bloom, and although it's too late for this year, next year will always be better!
I also detected a second cause for your sedum's troubles. In studying your photograph, I noticed extensive insect damage to the sedum leaves, and I believe the insect responsible probably damaged flower buds also.
Insects were prolific on many flowers and vegetables this summer, with high populations possibly spurred by plentiful moisture and warm temperatures. Bean leaf beetles, flea beetles and corn rootworm beetles attacked in large numbers, and these insects often migrate to flowers also.
All-purpose flower and vegetable insecticides that are handy to keep on the garden shelf include Sevin, Eight and Spinosad. All three are broad-spectrum products that are useful for controlling many insects on many plant types, always following label instructions, and applying at the earliest sign of insect activity.
Q: Can you identify a mushroom for me that's growing in my yard? -- Barbara K.
A: I'm frequently asked to identify mushrooms, mostly from residents wondering if they're edible types. North Dakota State University doesn't have anyone, myself included, who is trained in mushroom identification. Mushrooms and other fungi are in a biological kingdom all their own, separate from the plant, animal and bacterial kingdoms, so they require specialists educated in that kingdom for proper identification.
Because some mushrooms are deadly poisonous, even those educated in that science usually hesitate to identify mushrooms for others, especially from photos. Misunderstandings or misinterpretations about an identification could end badly.
Instead, if mushroom identification is wanted, there's a useful tool with which we can self-identify them. And if someone feels confident enough in the identification they've made, they can determine for themselves whether or not to consume them.
The University of Minnesota Mycology (study of fungi) Club has assembled a wonderful set of flashcards with photos and descriptions of the mushrooms commonly found in the Upper Midwest, which can be found at https://www.umnmycologyclub.com/resources/flash-fungi-id-cards.
Q: Is it true that rhubarb shouldn't be used after a fall frost? We've heard it becomes poisonous. -- Denise M.
A: Rhubarb leaves contain oxalic acid, making them inedible, which is why they're always discarded after harvesting the stems. During the food shortages of World War I, rhubarb leaves were consumed by some, and toxicity was reported, although it's been debated whether it was actually deadly. At any rate, rhubarb leaves are not to be eaten.
After frosts of 32 degrees Fahrenheit, whether it's in spring or fall, some oxalic acid might travel from the leaves into the stems if the plant is visibly damaged by the freezing temperatures.
As a general safety recommendation, if after a frost, the leaves and stems are wilted and show obvious frost damage, the stems should not be eaten. After spring frost, damaged stems can be removed and discarded, and future normal regrowth is safe.
If, after a frost, the rhubarb leaves and stems are turgid and appear unaffected, the rhubarb stems are considered safe to consume.