Gardening Column

The OSU Extension Office is located at 505 N. Columbia River Highway in St. Helens and can be reached at 503-397-3462.

The dry summer damaged some trees and shrubs, killed others, but many were not harmed at all, even in the areas that weren’t watered.

Tree growth slowed way down and several deciduous trees developed some nice fall colors early. Fear of fire was ever-present this season, but we generally escaped without any serious events. We all were alert, careful, and probably a bit lucky.

Fall can be an excellent time to plant trees and woody shrubs. With good soil moisture and mild temperatures, the root systems of the new transplants can get a head start on the next growing year. Don’t dig a hole that just fits the root ball. Instead, create wider circles of worked ground to the depth of the root ball so that the roots can spread out nicely. The base of the root ball should be on solid soil with the worked soil placed around it to the height of the root ball. If the root ball has lots of circular roots, try to unwind them to encourage outward growth rather than roots that continue to circle around the root ball. That can kill a tree over time.

Mulch with 3-4 inches of rough bark chips, keeping the chips at least three inches from the trunk. Modern practice tries to avoid staking trees but if it is a really windy site, a stake support system that allows some trunk movement will help strengthen the trunk. Finally, as I mentioned in a column several weeks ago, consider “white-washing” the bark within 3-5 feet of the ground with a 50/50 mix of white latex paint and water on a nice, dry day. This will reduce trunk winter injury and summer sunburn.

Slugs mostly disappeared in the heat, even in watered vegetable gardens. But they are back and making up for lost time. That means eating and breeding. Gardeners prefer they do neither. So, it is time to bait or use other means to reduce damaged lettuce and egg production. Baits are reasonably effective but need to be reapplied about every three weeks until it gets a lot colder. Metaldehyde based baits can be pet toxic but very effective while iron based baits ones aren’t pet toxic but may be somewhat less effective. Read and follow all instructions.

Alternate techniques include drowning them in beer or a water/molasses/ yeast mix (getting the dead slimy mass out isn’t pleasant); putting down boards for them to hide under and turning the boards over the next morning to whack the slugs, sushi chef style (some people, instead, pick them up and drop them into soapy water in a bucket); or letting your chickens and ducks (if you have them) forage for their slug meals.

By the time you see this, we may have had a frost. If so, your winter squash still outside may have been injured. Harvest them now (most vines have few really active leaves so there won’t be much more growth anyway). Check them out use the ones that show damage soon.

Our nice tomato season ended for most of us with the rain. Those with good shelters for their plants can expect tomatoes into November, assuming you can shut the shelter down on cold nights. There used to be a gardener in Columbia City that had an Adirondack type shelter for his tomatoes. It had clear plastic on three sides and the roof and was open on one side for ventilation. No rain got to the tomatoes and he controlled the watering. If frost threatened, he closed down the open side for the night. It worked wonderfully.

If you need to treat moss on your roof, now is the time to do it. The rains have turned the moss green, which makes it susceptible to zinc monohydrate, the active ingredient that does a good job on roof moss. It can be sprinkled on or mixed into a spray and sprayed on. Pick a day when it has been dry for a day or so, to reduce any chance of slipping off the roof. You can hire roof maintenance companies to do this work as well.

Will there be an OSU Master Gardener class next spring?

We are actively planning for an in-person OSU Master Gardener class starting next February. The class would most likely be held on Monday, during the day, for about ten weeks. If you think you might be interested, let us know. Call Sonia Reagan or myself, Chip Bubl at 503-397-3462. Your statement of interest doesn’t commit you to anything but will give us some idea if people are ready to return to in person classes. If COVID mutates again, it might have to be a digital only class.

Important notes

  • The OSU Extension Office is fully reopened. Masks are still required inside.
  • Donate produce and/or cash to the food bank, senior centers, or community meals programs. It is greatly appreciated.
  • The Extension Service offers its programs and materials equally to all people.

Have questions?

If you have questions on any of these topics or other home garden and/or farm questions, please contact Chip Bubl, Oregon State University Extension office in St. Helens at 503-397-3462 or at The office is open from 8 a.m. - 5 p.m. Monday through Friday.

Free newsletter

The Oregon State University Extension office in Columbia County publishes a monthly newsletter on gardening and farming topics (called County Living) written/edited by yours truly. All you need to do is ask for it and it will be mailed or emailed to you. Call 503-397-3462 to be put on the list. Alternatively, you can find it on the web at and click on newsletters.

Many Extension publications available online

Are you putting up salsa, saving seeds, or thinking about planting grapes? OSU has a large number of its publications available for free download. Just go to Click on publications and start exploring.

Contact information

Oregon State University Extension Service – Columbia County

505 N. Columbia River Highway

St. Helens, OR 97051



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