Helen Chesnut's Garden Notes: Fall is time to control a spring pest

Dear Helen: This spring, in our Garry oak meadow, there have been what looked like large numbers of little black bits like coffee grounds falling from the oaks. What were they? Could they be coming from the green worms hanging from the trees?


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The dark specks are most likely frass (worm excrement) from the tiny green caterpillars you have seen on silken threads. These are winter moths, a major pest of Garry oaks on southern Vancouver Island. Similar is the Bruce spanworm.

The larvae feed on flowers, leaves and buds from early April to late May or mid-June. They pupate in leaf litter beneath the trees, to emerge in the fall as adult moths to mate and lay eggs in the trees. That is the time to undertake a major control measure.

Because the female moths are flightless and must climb up the tree trunks to lay eggs, they can be trapped by wrapping the trunk with a 25 centimetre-wide band of plastic wrap or parcel tape and applying an insect glue, such as Tanglefoot, over it. Do this in mid-October, and remove the band in February.

Dear Helen: To encourage bee activity in my spring garden for promoting better pollination and improved yields in my fruit trees, I have added winter heathers, crocus, Oregon grape and (over-wintered) kale to the garden for spring flowers to feed the bees. Would setting up mason bee nests help, or do fruit trees flower too early for them?


Native blue orchard bees are highly recommended for gardens with fruit trees. Their season begins, that is they emerge from their nesting sites, about the same time as the beginning of plum and cherry tree bloom. That's usually when daytime temperatures reach 14 C.

The female bees are active through May, gathering nectar and pollen to place as food packets with the eggs they lay. This food will nourish the larvae that hatch from the eggs.

In her book Victory Gardens for Bees, Lori Weidenhammer recommends putting up at least one condo for blue orchard mason bees, which she describes as super-efficient, eager pollinators that will deliver a “big payback” in improved quality and quantity of fruit and nut tree harvests. “Look for them in cherry trees, Oregon grape or flowering kale from April to June.”

Weidenhammer provides a life cycle and management calendar for the bees. Similar information can be found in the West Coast Seeds catalogue, which also lists several types of nests as well as cocoons, which are shipped during the dormant season for setting outdoors, in nests, in spring. Some local garden centres carry complete mason bee supplies.

Garden events

Nanaimo meeting. The Nanaimo Horticultural Society will meet tonight at 7 in First Unitarian Fellowship Hall, 595 Townsite Rd. Amy Robson will speak about Alternatives to Grass. A parlour show will feature judging of spring flowers and early vegetables. Information at 250-758-6783.

Floral art. The Mid Island Floral Art Club will meet on Thursday at 2 p.m. in St. Stephen's Church Hall, 150 Village Way in Qualicum Beach. Pat Scrivener will present Inspiration for Creativity. Scrivener combines line, colour and texture to create floral designs sure to inspire creativity in others. Visitor fee $10. Information at 250-752-1858.

Summer show. View Royal Garden Club will hold its Summer Garden Show of flowers, fruits and vegetables on Saturday from 1 to 3 p.m. in Wheeley Hall, 500 Admirals Rd. (behind Esquimalt United Church). The show is judged by accredited B.C. judges. Admission of $5 includes refreshments and door prize tickets. The show will include a sale of plants and garden items.

Garden party tour. The Urban Wildlife Stewardship Society and B.C. SPCA are hosting a Father's Day tour of eight lovely Oak Bay gardens on Sunday, 11 a.m. to 5 p.m., with afternoon tea, a sale of drought- and deer-resistant plants, a silent auction and master gardeners answering questions at Windsor Pavilion, 2451 Windsor Rd. in Oak Bay. The gardens feature a variety of styles from English, native, small and cosy to large and expansive. Tickets at $25 available at spca.bc.ca/gardentour; at B.C. SPCA Victoria Branch, 3150 Napier Lane; Ivy’s Bookshop, 2188 Oak Bay Ave.; GardenWorks Oak Bay, 1916 Oak Bay Ave.; and Thorn & Thistle Flower Shop, 713 St. Patrick St.

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