Gardening with Chip

Winter planning: Containers

Plants in landscape containers can have issues in winter. If very cold temperatures last for several days, roots in the containers may be killed. It takes really cold weather - normally around 15 degrees or less - to see this happen.

Gardeners are surprised that plants that should be able to tolerate those temperatures based on “zone” ratings are often affected. However, the zone hardiness ratings assume that the plant is in the ground and the roots are protected by a mass of soil. Roots of a given plant are generally not as hardy as the trunk and branches of the same plant. Put the roots into a more exposed situation (like in a pot), and the plant may not survive temperatures that wouldn’t have killed the same plant in the ground.

Think ahead to where you might temporarily move container plants if really cold weather shows up. Some gardeners put them into unheated but enclosed garages. That is generally sufficient to keep them from damage. If you had a large sawdust or mulch pile, the pots could be sunk deep into the pile and the insulation provided by the mulch would shelter the roots. Plants can also be grouped close together with a blanket or other insulating material thrown over them. This is standard practice in nurseries where you see large acres of containers covered in heavy “frost blankets,” which are basically very thick row covers. Finally, you can hope for snow before temperatures drop. Snow is an excellent insulation if it is deep enough around the container.

If you have zone 8-9 plants and we get a zone 5 winter, plan on replacing some of your less hardy plant material, even those planted in the ground. This may become less common, since climate change has moved us into a zone 8a or 8b, but we are too far north to not be surprised at times.

Voles in the garden

I mentioned voles (meadow mice) in passing but have had many comments about voles. I thought more information on control might be helpful.

Many have discovered that vole numbers have exploded. No one knows why. These rascals can damage a lot of woody plants in the winter. Most vegetation damage blamed on moles is actually caused by meadow mice.

So, what can you do? Reduce their hiding places by tight mowing and removing plastic mulches. This is very important around young trees since voles seem particularly attracted to young bark. I once went to a garden that had about 25 rose plants in a bed. The ground was covered with plastic mulch for weed control. When the gardener went out to prune their roses about this time of year, they started falling over as they were trimmed. Most had little if any woody root system left, due to fat and protected voles!

Meadow mice don’t seem to be the brightest animal on the block. They have devoted their evolutionary energy to reproduction. Many voles are having youngsters within six to eight weeks after they are born.

Collapse mole tunnels that give voles access to tree trunks, tree roots, and your root vegetables left in the garden. Knocking in tunnels is a hard task since there can be lots of tunnels in a relatively small area. But it helps. Persistently trapping moles will help reduce tunnels.

Mouse traps work!

Voles can be trapped repeatedly in the same area with the same bait (most use peanut butter). The voles don’t seem to get the picture. Find where to place the traps by putting apple slices out under a board over vole pathways to see if they get gnawed. Locate the traps in a dip and underneath something so that birds won’t get inadvertently trapped. There must be enough free space for the trap to close normally.

There are some newer snap traps that take less space for the trap mechanism to work and are also easily thumb set. These traps are readily available, and I have found them to be effective.

Baits are very restricted around home gardens and landscapes. They can be deadly for birds, pets, and other species that eat poisoned voles or vole baits! I can’t recommend them.

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.

Sign up for master gardener training in either county.

Very helpful information sources are your local Extension offices. The Columbia County Extension is 503-397-3462 and the Wahkiakum County Extension is 360-795-3278. Those of you in Columbia County should get to know my replacement, Janhvi Pandey, a very nice and talented person with a strong agricultural and gardening knowledge. The Extension Service offices offer their programs and materials equally to all people.

Advice on future garden topics is always welcome by emailing me at chip.bubl@oregonstate.edu.