Q: What type of shrub is in the photo? We’d like to trim it. Any suggestions? — Ken and Jenny Rustad.
A: The red-flowered shrub is weigela, probably the popular cultivar Red Prince. There are various ways to pronounce weigela, and I was taught to say “why-JEE-luh.” The shrub is generally winter-hardy for our region, but like many shrubs, it can have occasional branch dieback.
Remove any dead branches back to their base. Weigela can be trimmed a little during summer to develop a natural shape, or to maintain a certain size. These shrubs are prone to becoming overly woody in time, and a rejuvenation-type pruning every three to four years helps maintain healthy, vigorous branches and prolific flowering. Such heavy pruning is best done while the shrub is still dormant in early spring, and cutting back to 6-12 inches above ground level encourages fresh new growth.
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Q: We will be moving in August and I need to move my Centennial roses. Do you have any helpful suggestions to make the move a success? — Jan Olson.
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A: The preferred time for moving roses with the greatest chance of success is while they are still dormant in early April. But we don’t always have that option.
In August, extra caution will be needed to increase the likelihood of success. Use old nursery pots or 5-gallon pails with drainage holes drilled in the bottom.
Begin by cutting the rose back by at least half to two-thirds to compensate for the roots that will be lost. That step is extremely important for transplant success.
Start digging the rose about 12 inches away from the base. You might need to go closer than that, so the root ball will be manageable. As quickly as you can, get the root ball into its pot, and add potting mix or soil below and around the roots. Then water immediately, thoroughly soaking all the soil.
The roses should transport fine, and be capable of staying in the container for several weeks, if necessary, until you are able to plant it in the new location. During the move, remember to put the potted roses in sunlight as often as you can, not tucked away in a dark moving van or other no-light locations for extended periods.
Best wishes for a successful move for both you and the roses.
Q: Is there a spray for quackgrass that doesn’t kill flowers? — B. Youngberg.
A: Herbicides have several modes of action and types of plants they kill. Some specifically kill only broadleaf plants, some kill only grassy plants, and some herbicides kill all plants.
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To remove quackgrass from a perennial flower bed, there are herbicides that selectively kill only grassy plants without harming non-grass perennials. These products can be applied over the tops of flowers and shrubs, always following label directions, and they will kill quackgrass that is growing among the desirable plants. Two such grass-killing herbicides are Ortho Grass-B-Gon and Bonide Grass Beater. I’ve found these products to be slow-acting, so patience is needed, and results might not be evident for seven to 10 days.
Quackgrass has additional dormant buds as a backup system for survival, which often kick into action when its other growth is killed. That’s why it’s usually necessary to treat quackgrass a second time, after any regrowth emerges. Persistence is the key to many of these difficult-to-kill perennial weeds.
ARCHIVE: Read more of Don Kinzler's Fielding Questions columns
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at kinzlerd@casscountynd.gov or call 701-241-5707. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.
