Winter is a good time to look at your deciduous shrubs and trees without all those pesky leaves getting in the way. Look at your evergreens too, just so they don’t feel bad.
Without the leaves, the branching structure is revealed and it’s easier to do some pruning. You can prune out what we call interfering branches—branches where two cross and rub against each other and watersprouts—vertical branches growing from a lower branch up or trunk up into the main plant. Or just remove some branches to give the plant a nicer shape. Advantages of winter pruning include being able to see what you are doing, a reduced possibility of spreading plant diseases around with your pruning tools, and not removing leaves from the plant during the growing season when they are full of carbohydrates and other stuff that the plant absorbs before the leaves turn color and drop in the fall. Disadvantages include removal of next season’s flower buds in some cases, and frostbite.
If you have cherry trees, this is a good time to look for and remove the egg masses of tent caterpillar moths. They will be on the branches or trunk and look like bits of smooth black foam about the size of a wad of used chewing gum. Scrape them off (into the trash) and you’ll have less of a problem with these pests next spring.
On your evergreens especially (but also occasionally on Japanese Maples and other deciduous plants), look for bagworms. They look like little Christmas tree ornaments, waving merrily in the breeze, tan, about an inch to an inch-and- a-half long. What you see is actually a protective structure made of bagworm silk with bits of needles attached for disguise, made by bagworm caterpillars as they feed and grow, living within the bag and sticking their heads out to feed, sort of like a turtle in a shell. While the male bagworm caterpillar eventually becomes a small moth and leaves the bag in search of a female, the female never leaves the bag that she constructs. After being fertilized by the male, she lays up to a thousand eggs in this cocoon and then dies. So next year’s destructive bagworm caterpillars are easily reduced by picking these bags off the plant and discarding them in the trash. These pests can completely defoliate an evergreen like a dwarf Alberta spruce, so it’s important to keep them under control.
I haven’t seen gypsy moth caterpillars in a number of years, but they do flare up from time to time and can totally defoliate trees including oaks. If you see something that looks like a piece of tan felt, oval and about an inch or inch-and- a-half long attached to a tree trunk (or your house, or just about anywhere), it’s probably an gypsy moth egg mass. Scrape it off and dispose of in the trash. For all these eggs, scraping them into a jar of alcohol will kill them, although then I’m not sure what to do with the alcohol.
If we have a mild day (like it is as I am writing today, 60 degrees in December), it’s a great time to spray deer repellent. Deer will be focused on evergreens now, and deciduous tree/shrub buds. Spray azaleas, arborvitae, yews, any plant where you have had problems in the past. They love my neighbor’s Aucuba, so I sprayed that and my azaleas today, after I noticed they had chewed off the top of an ash tree seedling.
So, not as much fun as a trip to the beach, but it gets you outside, and if you have kids, you can look for these egg masses together, and you can all get cold and go in for some hot cocoa.
by Larry Hurley, Behnke horticulturist