Kinzler: Creeping Charlie, trimming evergreens and ripening pumpkins
In today's "Fielding Questions" column, a reader wonders what they can do about this weed spreading on the side of their house.
Q: This plant is spreading on the west side of my house. Can you identify it, and what can I do about it? — Martin Ness.
A: The weed in your photograph is creeping Charlie, sometimes called ground ivy. Early settlers brought this non-native plant to North America from Europe, as they felt it would make a hardy groundcover. And that it is. Unfortunately, it escaped cultivation long ago, and is now one of the most tenacious weeds in the lawn and landscape.
Creeping Charlie is a winter-hardy perennial, spreading by creeping stems that root as they crawl. Blue-lavender flowers produce seed, making a second source of spreading. In lawns, the low-growing plant habit hugs the ground, escaping the lawn mower.
Fall is the most effective time to control hard-to-kill weeds like creeping Charlie, and an effective active ingredient is the herbicide triclopyr, which can be found on the label by examining products at the garden center. Apply triclopyr spray in September after the first light frost. This fall application is very important, as weeds are moving material, including the weed killers, down into their roots for winter storage.
Repeat application next May or June when creeping Charlie is producing blue flowers. Triclopyr is a broadleaf weed killer, killing broadleaf plants but not harming lawngrass. In landscapes and flower beds, herbicides must be spot-applied, as chemicals that kill creeping Charlie will also kill broadleaf perennials, trees and shrubs.
Always follow the directions on the label. Triclopyr can cause damage to trees, because it can move downward in the soil and enter roots, so should not be applied over the rootzone of trees or shrubs.
Control by digging is difficult, yet might be the only solution in perennial flowers or landscapes. Care must be taken to remove every sprig of Charlie’s stems. Alternatively, perennial flowers can be dug out in early spring or fall, set aside in pots, and creeping Charlie treated with herbicide.
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Q: I feel it’s too late to be trimming yews and other evergreens. Am I correct, and when is the proper time? — Marlys C.
A: Yes, it's generally better not to trim evergreen in the fall, as it can open them up to greater winter injury. Generally, all evergreens are best pruned in May and June, about the time their new growth is emerging or expanding. Of evergreen types, arborvitae are a little more flexible about timing of pruning, because they continue growing throughout the summer.
Q: I have a question about pumpkins. I was cutting pumpkin vines in my corn patch that I thought didn’t have fruit, when I cut off the main vine of a large pumpkin. It had just started to turn orange. Do I leave it in the garden or bring it in? Will it still ripen? — Brenda.
A: If pumpkins are showing a little bit of orange, they’ll usually progress to full color, if given warmth and light. If outdoor daytime temperatures will be close to the 70s, it’s fine to leave the pumpkins in the garden, exposed to sunshine.
If weather conditions don’t cooperate, pumpkins can be moved to a sunny, warm location, such as a south-facing porch. Occasionally rotating them toward the sunlight will promote uniform orange color.
Pumpkins can tolerate light frosts fine, but temperatures between 25 and 28 degrees or lower can make them soft and water-soaked, especially if they haven’t developed a hard shell yet. If additional hard freezes are forecast, moving the pumpkins into the garage on cold nights and back to their warm, sunny spot during the day will keep their color progressing to bright orange in time for Halloween.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at firstname.lastname@example.org or call 701-241-5707. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.