Dear Helen: Leaves on the tips of new growth on my apple trees are twisted and curled. What can I do about it?
Aphids cause this leaf distortion by gathering on the leaf undersides and sucking sap from the youngest, most succulent tip growth of the trees. Often you’ll see ants moving up and down the branches as they visit groups of aphids and feed on the sweet honeydew that the aphids secrete.
Summer pruning, which helps to keep the trees compact, removes the aphids. Shorten stems to leave just two or three leaves on the new (this year’s) growth.
Always inspect trees and other aphid-infested plants before pruning or using any other pest controls, in case aphid predators are already at work cleaning up the problem.
Last year at this time, I was pruning away aphid clusters from one of my apple trees when I began to notice ladybugs (lady beetles), and patches of their yellow-orange eggs, on the leaves. I stopped, and delayed the rest of the pruning until the lady beetle nursery had finished raising its young. Both adult lady beetles and their larvae are voracious predators of aphids.
After pruning, consider spraying the trees with a jet of water from the hose to help clean off malingering aphids. Repeat the water spray every two or three days. Encourage lady beetles and other predators with flowers that attract and feed them. Sweet alyssum, cilantro and dill are among the best. They can be seeded now. Or buy alyssum transplants.
Keep apple trees adequately watered and avoid supplying an excess of nitrogen to the soil. Too much nitrogen fosters soft, succulent stems and leaves that are especially vulnerable to aphid infestations.
Dear Helen: I have a tree peony that has become overgrown and sprawling, like so many shrubs in my garden this year. I’ve heard that tree peonies must not be pruned hard, but my plant needs a major cutting back.
Rampant overgrowth is a common theme this spring and early summer. People are stopping me on the street and in grocery stores to speak about their jungle-gardens.
Over time, tree peonies have a habit of developing bare, leggy stems, which can become a nuisance if they take to leaning over a pathway or onto nearby plants. The remedy is to simply cut these old, bare stems to the ground.
Removing an overgrown stem is considered preferable to shortening it by cutting into old woody growth, though as an experiment I have done this with one of my tree peonies. I made the cut right over a node (bump) that indicated a point or origin for potential growth. I chose a node that pointed upward, to correct the lean of the long stem.
It worked. New, upright growth developed to reshape the shrub; however, my tree peonies are seed grown (Paeonia lutea). Purchased hybrid varieties may not sprout from old wood so well. You might consider experimenting on one of the least conspicuous bare stems. If it doesn’t re-grow, you can always cut it to the ground.
If you decide to tidy the plant by removing a long, bare stem or two, clean up around it afterward and apply a nourishing compost mulch layer to help encourage the production of new stems.
Though the plants do well in a fertile, humus-rich, moist soil, to keep growth as sturdy and compact as possible, take care not to over-water or overload the soil with nitrogen.
Government House plant sales. From 9 a.m. to 12 p.m. on Tuesdays and Thursdays this summer to Aug. 31, the Government House plant nursery (next to the tea room) will be open for public plant sales. Proceeds go to the maintenance and enhancement of the gardens at Government House, 1401 Rockland Ave.
Point Ellice garden tour. Point Ellice House, 2616 Pleasant St., is hosting “an 1867 garden in 2017,” an historical tour of the past, still blooming in the present, on Saturday, 2 p.m. Walk through the garden with its head gardener and learn the history of roses and other plants cared for by the O’Reilly family, the home’s original owners. Admission is by donation. There will be heritage plants for sale. pointellicehouse.com. 250-380-6506.
Nanaimo tour. The Nanaimo Horticultural Society is marking its 70th anniversary by hosting a free tour of six members’ gardens on Sunday, July 16, from 11 a.m. to 3 p.m. Details are available at nurseries and libraries from Ladysmith to Nanoose.