Q: This morning I picked a bouquet of these flowers from a shrub at the corner of our home and brought them to church. So many people asked me what they were and I don't know. Can you identify them? — Sue Ellingson.
A: The beautiful flowers are from the shrub called Rose Tree of China, also known as double-flowering plum. The botanical name is Prunus triloba multiplex, and it’s in the plum family, although it doesn’t produce fruit.
Rose Tree of China is winter-hardy in our zones 3 and 4 and can become a large shrub, growing 10 to 12 feet high if untrimmed, although it’s commonly maintained at between 6 and 8 feet. Eventually the older branches become woody and unproductive, so occasional pruning is needed to remove the old branches and stimulate fresh branches that flower more abundantly. The attractive double blossoms are born along the branches in May. The shrub maintains green foliage the rest of the summer.
Q: I'm wondering how vigorously to prune a 20-year-old William Baffin rose that has grown to at least 12 feet tall. It is not on a trellis. There are now about five crowns and it blooms prolifically. There are some new canes, but most are totally bare for about one-third of the height, and it’s now unsightly. Should I cut everything back to the lowest bud or pruning all canes down to 6 to 12 inches? — Diana Rankin.
A: William Baffin is a wonderfully winter-hardy rose developed through the Canadian breeding program. Although it’s not a true climbing rose that twines itself around a support, it’s called a climber because it produces long canes that can be attached to a trellis or arbor with twine or wire.
In time, the canes of William Baffin become old and woody, and the lower portions tend to be bare, as you’ve found. The best rejuvenation of old, woody roses is to prune all canes back to 6 to 12 inches above ground level in spring or early summer to encourage full, energetic growth from the base. Alternatively, one-third of the canes can be cut back each year over the next three years for a gradual rejuvenation, but I favor the first method.
Q: I am going to be away from home for the months of June and July, so I won’t be able to weed my perennial flower beds. What do you suggest to keep weeds under control during that time? — Marlene O.
A: There are several options. You can apply Preen weed preventer now before weed seed germinates, or right after the flower beds are cleanly cultivated. Preen is a pre-emergent granular herbicide that prevents seed-grown weeds from becoming established. It doesn’t control weeds that are already growing, nor weeds that grow from underground roots and rhizomes, like quackgrass and thistle. Follow label directions by watering the treated area after application to activate the Preen, or lightly cultivate into the soil surface, as exposure to sunlight can weaken the granules’ effectiveness.
Another option for weed control is applying mulch between the perennial plants. If mulches such as shredded wood products are used alone without an underlayment, they should be about 5 inches thick to be effective in smothering weeds. A handy underlayment that eventually decomposes naturally is newspaper. If a 10- to 20-page thickness of newspaper is used over the soil surface, the amount of mulch can be reduced to several inches spread over the paper. Dried, untreated grass clippings can also be used as a mulch instead of shredded wood.
If you have a gardening or lawn care question, email Don Kinzler at ForumGrowingTogether@hotmail.com. All questions will be answered, and those with broad appeal may be published, so please include your name, city and state for appropriate advice.