What to do this week Fall is savored for its quiet beauty and crisp, clean air. But what is that terrible 100-decibel noise? Has the Indy 500 moved next door? Please don’t hire lawn companies that use highly polluting gasoline-powered leaf blowers, which can ruin a fall afternoon for neighbors, including me. Electric blowers work just as well. A 2011 test by the car experts at Edmunds found a two-stroke gasoline leaf-blower engine generated 23 times the carbon monoxide and nearly 300 times more non-methane hydrocarbons than a high-performing pickup truck. That’s equal to 4,000 miles, a drive from Texas to Alaska, for an hour of leaf blowing, according to the report. Hydrocarbons are linked to smog and cancer. Gasoline blowers also emit formaldehyde, acetaldehyde, and benzene. Not what I’m looking for from a perfect fall day. The Outdoor Power Equipment Institute has lobbied successfully in Washington against state regulation, but we as individuals can use electric garden equipment and ask for it from the lawn crews we hire.
Q. I am growing milkweed to encourage monarch butterflies. When can I safely cut it down without hazarding eggs, caterpillars, or pupae? Should it be left standing until spring?
A. It should be safe to cut it down in late fall. Most monarch butterflies migrate to Mexico in September and October, but wait until the milkweed seeds float away on their silken parachutes so they can reproduce. The empty seed pods can look pretty if left standing through the winter. My garden club makes Christmas decorations from them. All milkweeds, except tropical species, will grow back next year whether you cut down the tops or not.
Q. I’m moving my favorite sedum to my summer home. Should I cut back the spent blooms or transport them as they are? Space in the car is limited.
H.C.B., Ossipee, N.H.
A. The tops of sedums and other perennials will soon be as dead as fingernail clippings, so cut them back now if that’s convenient. Many people leave the skeletons of sedums, astilbe, ornamental grasses, and milkweeds standing as winter garden architecture or cover for birds and hibernating insects. You can cut the tops down now or wait until live shoots sprout in March and April. Unlike woody trees and shrubs, the only living part of a perennial during winter is its underground roots.
Q. I “discovered’’ fresh garlic in a CSA this past summer. Excitedly I planted several bulbs in a pot and now have healthy green shoots. But it seems garlic needs more time to mature. Can I transplant these bulbs into a raised bed box to grow through the winter?
A. It is not too late to plant garlic. As long as the soil is not frozen, it can still be planted. Sunny raised beds are best. Plant it pointy end up like a tulip bulb, 4 inches apart and 2 inches deep. Then water and mulch and leave it alone until you harvest it in July after the leaves and stems start to brown.