Gardening with Chip

Fall is just getting started and one thing is certain. As we get cooler nights, some insects start looking for places to snuggle in. They think this is a good idea. It isn’t, both for them and you. Most of them will not be able to find their way out of your home in the spring and they will die. A friend of mine was once remodeling a house and planned on adding insulation to the 80+ year old house. He didn’t think there was any insulation in a house that old. But as he removed some of the exterior siding, he was astonished. The wall void was packed full of the bodies of box elder bugs, cluster flies, and other insects that had made the wrong life choices over the last 80 years. He did remove them but also wondered whether he really needed to since they probably provided significant insulation.

Outdoor insects like box elder bugs spend their spring and summer with the maple trees they feed on or, in the case of cluster flies, the earthworms they lay their eggs in. We do know that box elder bugs like to winter in the deep bark furrows of Douglas fir trees. Before Europeans got here, they also found the indigenous population structures just nice and cozy.

The best house defense is caulk, lots of it. The tiny gaps around window and door frames are common entry points for them to wriggle through. Also vulnerable are roof ventilation hardware and spaces around chimneys. Anything you can caulk will reduce the population of box elder bugs and the many other insects that look for comfort inside. Insecticides rarely get more than a fraction of the box elder population looking for winter digs.

Some other insects you may see in your home include some tiny beetles that feed on pollen and tender plant parts and move in when they dry up; the brown marmorated stink bug which is making a resurgence; the Asian multicolored lady beetle; pregnant overwintering wasp and yellow jacket queens (rather upset if they wake up and can’t find their way out); wood-boring insects if you are bringing in firewood; earwigs; and carpet beetles. Some non-insect winter living partners are centipedes, millipedes, and spiders. Most mean you no harm and most don’t do real damage.

Pantry pests, which we will get to in another article, are more complicated and can be a real problem. For all, the best way to keep them out is not insecticide sprays but tight entrances to your home. On newer houses, TyVec and similar moisture and heat barriers do make a difference on insect numbers.

Finally, here is the answer to one question that kept more than a few of my Extension clients awake at night: Do box elder bugs mate in the house? The answer is, no, they don’t. They save that for the great outside (assuming they can find their way out).

Hold off on pruning

Most pruning is done when trees or shrubs are truly dormant. There are some exceptions. Whole limbs can generally be removed at any time. So can dead or damaged wood. Some gardeners feel in this climate that evergreen hedges do better with fall rather than spring shearing though I’ve never seen real data on that.

For most deciduous woody plants, pruning now can stimulate “soft” growth that is prone to freeze damage. It can also keep the plant as a whole from responding to the decreasing day-length in the fall that cues the plant to begin the winter shut-down cycle. This makes the entire plant more susceptible to cold injury. So get your garden beds in shape, plant garlic and attend to all the other garden projects normal to the fall but keep your pruning shears holstered until January/February.

Gardening notes

Western Cedar “flagging”

This seems to be especially obvious this year on our native western red cedars. Evergreen plants naturally shed some old foliage each year. Stress factors, such as insufficient water, hot winds, construction damage or other root disturbance, poor planting procedures, or recent planting can promote flagging.

Symptoms: Brown foliage develops on the tree or shrub in mid to late summer and is very obvious by early fall. Affected foliage is growth from previous years. Foliage developed during the current year (at branch tips) remains green. Brown branchlets, called flags, generally are spread uniformly through the canopy. Affected foliage may begin to drop in hot, dry weather. Most of the dead foliage is blown or washed out of the plant by wind and rain in fall and winter. The plant typically resumes its healthy appearance by spring. Adopted from the PNW Plant Disease Handbook

Voles, also known as meadow mice, can do a lot of damage in gardens. They will gnaw and girdle young trees, eat bulbs and chew the roots of herbaceous plants. Holes about the size of a quarter indicate a problem.

Keep the grass mowed around young trees to make the mice nervous and the predators happy. Try to collapse mole runways that the mice use. Trap as a last resort.

Lime your vegetable garden once every three or four years. Apply 100-150 pounds per 1,000 square feet. Work it in now if the soil is dry enough (not likely) or next spring.

Take excess produce to the food bank, senior centers, or community meals programs. Cash donations to buy food for the food banks are also greatly appreciated. This is especially true now, since many of the federal food funds that helped the food banks have been cut hard.

Very helpful information sources are your local Extension offices: Columbia County Extension 503-397-3462; Clatsop County Extension 503-325-8573; Wahkiakum County Extension 360-795-3278; and Cowlitz County Extension. 360-577-3014. The Extension Service offices offer their programs and materials equally to all people.

Advice on future garden topics welcome. Chip Bubl with OSU Extension Agent/Columbia County (retired) chip.bubl@oregonstate.edu (still can be reached on my OSU email). Those of you in Columbia County should get to know Janhvi Pandey, my replacement, a very nice and talented person with a strong agricultural and gardening knowledge.