It's already December!
Come December, if you have pottery that you won't be using for winter, it is usually a good idea to empty them and store them where they will either be dry or free of frost. Terra cotta is especially prone to breaking when frozen. Also, bird baths can freeze and take damage if made of clay or stone. That said, birds still need water when the air is below freezing, so you might consider some temporary plastic containers be placed out if you are emptying your clay bird baths. Autumn to early winter is a good season to start a regular winter feeding schedule for your birds with seed or suet.
When the weather is very cold and dry, your plants are more likely to suffer damage than in wet conditions or when snow covered. If cold, dry air is expected, water your plants beforehand. Make sure that you do not create puddles where someone might slip on an ice slick. Drain hoses and watering cans before a freeze. Consider having some burlap, bubble wrap, and/or frost blanket on hand for additional temporary protection during freezing conditions. In most cases, any wrap on plants should be temporary; do not leave it on all winter. Also, placing potted plants in semi-protected areas (up against the house, out of heavy wind) can give them a little help in winter.
It is not advisable to dig or disturb the earth when it is either saturated or frozen. Mulch any unused areas until conditions are more favorable for planting or digging.
Most of the leaves have fallen off of deciduous trees by mid-December, so it might be a good time for gutter cleaning, and watch for too much moss on the roof or walkways. We sell moss killing sprays for roofs, which can make the physical removal easier. To remove, use a long handled bristle scrub brush and scrape only down the slope of the roof. Scraping up can damage the bond between shingles. Always take precautions when working with roofs; moss and especially algae can be slippery and you are probably rather high in the air.
Brrrrr! Cold winds and a chance of snow!
Here are a few things you can do to protect your garden in winter weather.
Moist roots are much more durable in cold weather than dry roots!
Often our coldest weather around here comes with dry air and clear skies, sometimes with high winds. Make sure the soil around your plants is moist during these times. Moist soil is a better insulator than dry soil. Even if the water in the soil freezes, it is still better off moist.
Portlanders are lucky to live in a city with so much green space. Our combination of rivers, parks and mild climate allows Portland to host a vast array of birds and wildlife.
Birds are attracted to areas where the three basic needs of Cover, Food and Water are met.
As the light levels fall and summer weather gets pushed farther and farther into memory, we wonder if our gardens and porches have to look so desolate. The answer is “No!” Celebrate the season with a holiday hanging basket!
At Portland Nursery, we have all the supplies you need to create your own winter basket. Celebrate the season with the smell of conifers!
Pansies, ornamental kale and cabbages, dusty miller, and some evergreen perennials and grasses can all help to brighten up containers on the porch or entryway, or can be planted in ground if your soil is workable. This means that the soil is not waterlogged or frozen. With our infrequent snowfall, there is no reason you shouldn't be able to enjoy a little color in winter. Pansies usually can take a pretty hard freeze, and be right back in flower within a few weeks. Note that most garden annuals cannot be used now, and many perennials are dormant.
It might be a little late for any division or moving of in-ground perennials, unless your soil is workable. At this point, the sooner the better unless you wish to put the task off until spring. Dead annuals and frozen perennials can be cleaned up if you have not done so to make the garden a little tidier. As a possible alternative, stop to think about which of your plants might have seed or fibers still on them that would be good food or nesting for birds. Such plants you might consider leaving in place.
Empty garden beds can be mulched with leaves, straw, compost, or bark if this has not already been done. If your mixed beds contain trees or shrubs, do not pile mulch around the wooden trunks. Keep in mind that compost will improve to quality of soil, while bark and leaves are better for weed control.
If you have nice evergreen trees or holly, you might be tempted to take some clippings for holiday decorating. That is fine, but pay some attention to how the plants will look after you make the cuts. With conifers, do not cut back into hard wood, or the plant may not be able to re-sprout from under where you cut. Also, do not remove the central leader of a small tree. We offer many cut greens for sale to round out your selection of greens.
We carry a great selection of living trees at both locations. If you choose to decorate with a living tree, it is recommended to have your tree indoors for no longer than one week. Of course, you can have a decorated tree on the porch for the whole holiday season. For other holiday color, look for the outstanding Callicarpa: Beautyberry, Ilex: hollies, or the Cornus spp.: Red twig dogwoods.
Many deciduous trees prefer pruning be done during late autumn to early winter. Some examples are Acer spp.: maple, Betula spp.: birch, Carpinus spp.: hornbeam, Fagus spp.: beech, and Salix spp.: willow. Other trees take pruning anytime in winter, such as Styrax spp.: Snowbell , Lagerstroemia spp.: Crape Myrtlr, and Cornus spp.: dogwood.
Most fruit trees should not be pruned yet. If you have to make any major cuts on your shrubs (renovation pruning), it can be done in winter, but most shrub pruning is recommended for other seasons. Most deciduous shrubs can be pruned now, but if they are spring flowering you might want to wait until after they bloom. This is an acceptable time to prune grape vines.
See our Pruning article for more information.
Remove leaves from the lawn. If you are using your leaves as mulch in garden beds, it might be beneficial to shred them with the lawn mower before raking. The smaller pieces turn to compost more quickly, improving the soil in the spring. It is too late to fertilize your lawn effectively, and it is not a good time to seed, de-thatch, or aerate.
Moss is probably starting to encroach. You can use a moss control product, but moss will probably still grow back over the rest of winter. If you do, make sure the product you use is labeled for lawns; some moss control products can damage or kill your lawn. We sell some of the products useful for this. If your lawn has very bald patches, you might want to consider mulching the patches until spring to prevent weeds, and reseed then.
The only green vegetable that should be planted this late is kale. Existing cole crops (broccoli, cabbage, etc.) and lettuce or other greens can be protected with frost blanket or in a cold frame. If possible, harvest what you can before a hard freeze (significantly below freezing) and enjoy. Last chance for autumn planting of garlic and onions for harvesting next year.
Few vegetables should be planted in December, though kale may be an option. If you are working under glass or in a cold frame, other cold tolerant greens might work as well. Overwintering garlic and onions should have probably already been planted, but think of this as the last chance to get them in. The same goes for spring flowering bulbs: last chance to plant.
Slugs can persist throughout the winter, so keep an eye out if you are growing susceptible winter annuals or vegetables such as lettuce or primroses. Slug baits can still be used, though they might wash away in winter rains. Many weeds continue to grow in winter, and any weed you pull now will be many less in spring.
Visit individual month pages for gardening ideas. Pages are regularly updated with projects for that month.