Q: This fall I noticed a beautiful plant with purple flowers in people’s yards and also in some of Fargo city’s plantings. It looked like a mound-shaped shrub, and it bloomed right up until snow fell. I’ve attached a photo. Do you know what it is? — Kayla S.
A: The plant is generically called fall aster. There are many named cultivars, and the one in the photo is most likely Purple Dome Aster, which is available at many garden centers.
Although they look like shrubs, fall asters are perennial flowers that die back to ground level each winter. They’re fully winter-hardy for zones 3 and 4.
Purple Dome Aster reaches a height and width of about 18 to 24 inches. Purple Dome and other fall aster cultivars are among the most colorful fall-blooming perennials, beginning in late summer and flowering well beyond the first frosts of fall.
Fall asters can be divided in early May, just as new sprigs of growth begin emerging at ground level. One clump can produce multiple divisions, yielding plenty of new plants for perennial beds. Fall asters also blend nicely into landscape plantings, giving eye-catching color to the autumn landscape.
Fall asters definitely merit increased use.
Q: I just read your article on split carrots and thought I would pass along a method I use to store part of my carrots right in the garden over winter. — Duane M.
A: Thanks, Duane, for passing along your carrot storage tip. Duane writes:
“Unlike parsnips, which can be left in the ground during winter as is, you do have to pull carrots, break off the tops and rebury them. You can then lay them down, piled on each other, in a shallow trench and then cover them with about 10 inches of loam. It ends up looking like a grave.
“I then put a layer of bags filled with fall leaves over the buried carrots. If you just leave the carrots upright in place, the mice will eat down into them which they don't do to overwintered parsnips. It takes a bit of effort but it is worth it.
“During the carrot winter 'hibernation,' like overwintered parsnips, some of the starches convert to sugars and the buried carrots end up a lot sweeter than they were in the fall. What a wonderful spring surprise.”
Thanks for the tip, and I’m going to try it with a portion of our carrots. The soil isn’t frozen yet, so I’ll still be able to dig a shallow trench.
Q: When I pulled the ornamental sweet potato vines out of my patio containers this fall, I noticed there were several large sweet potato tubers underneath. Can they be eaten? — Judy N.
A: Ornamental sweet potato vines are a popular plant sold at garden centers for use in combination pots and planters. Some types have bright lime green leaves, while others have dark purple foliage.
Ornamental sweet potato vine is the same botanical species as the sweet potato tubers sold in grocery stores. Tubers from the ornamental vine are indeed edible, but reportedly not palatable. Ornamental varieties were selected for their attractive foliage, not their culinary qualities.
Never being one to pass up a horticultural adventure, I saved a tuberous root from our own ornamental sweet potato vine. I’m letting it cure for about two weeks, which in edible varieties converts starches to sugar, increasing the sweet flavor following harvest. I want to experience for myself the flavor of the tubers produced by the ornamental vines. I’ll report back.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at email@example.com. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.