December Gardening Calendar

December is a wet month in Humboldt County. "Good weather for ducks," is the quip heard as seasoned gardeners go about preparations for Christmas. And ducks there are, along with myriad birds of all kinds visiting the Humboldt Bay Wildlife Refuge while transiting the Pacific Flyway. Storms are part of normal December weather with snow in the hills.


Buy some white-blooming plants this month and you can create your own white Christmas on your front porch. Choose blooming azaleas and camellias in gallon size, and candytuft, cyclamen, pansies, and primroses in four inch pots. Combine them in large containers and add bows, holly, or some pine or even redwood branches.

This is the favorite month to plant TULIP and HYACINTH bulbs, for they need cool soil and growing conditions to produce good flowers on long stems. Planting depths recommended for other regions are not deep enough here to provide coolness. Allow 8 inches of soil above these bulbs in all but shady locations. If buds show color as they emerge from the soil, start pouring on extra water and the stems will lengthen.

The nurseries will be discounting all of their left over spring bulbs this month. Plant them as soon as possible. There are a few ANNUALS available at the nurseries such as primroses, pansies, and snapdragons. Unless you buy the larger plants they will just sit there and sulk until spring.

Later this month, nurseries will begin selling bare root roses, fruit trees, cane berries, strawberries, grapes, and perennial vegetables such as asparagus (UC 157 is a particularly good variety for our mild winter area of Humboldt County), horseradish, and rhubarb. They are gradually receiving their stock and will be in full swing in January. Have them place a hold on the varieties you want to ensure availability.

ENGLISH HOLLY is the plant of the holiday season. While red- berried varieties are justly popular, the equally cheerful yellow-berried form deserves wider use. Those with silver or yellow variegated leaves should be located in the garden with careful thought so they will not create a spotty effect.

While you are watching over your phlox by night you may notice that the PINES and other conifers look a little scraggly. They will be pruned in the spring, but if they need shaping you can do it later this month and use the cut branches for Christmas decorations. These also make good protection for tender young plants.

Pick up some red, white, or yellow ONION SETS while you are at the nursery and plant a few every other week until April, wherever you have a small spot, even in the flower beds. Crowd each planting together, and place the sets just under the surface. Use most as green onions and allow the outer ones to mature to full size.

This is your last chance to plant GARLIC if you want full size bulbs.

Clumps of CHIVES are breaking dormancy now. Separate the plantss and pot up some small divisions to give away.

You can still purchase and plant CABBAGE and other brassica plants, but these will grow very slowly, since the soil now has become cool. Wait to plant SWISS CHARD until later in the season, since doing so now may cause the plant to become useless when it bolts and goes to seed.

There are several different types of LETTUCE and SPINACH plants available. Plant them in a sunny spot since the secret to growing good greens in winter is rapid growth. Blood meal makes a great fertilizer, worked into the soil just below the surface. Insert 1/2 inch PVC plastic water pipes into the soil to form hoops over the row so you can cover the crop with plastic during the wet and cold periods. If your gardening area only comes in the wet and cold variety, consider building a cold frame to keep you supplied with winter greens and to start your spring seedlings.

Sow lettuce seeds indoors and set the plants out later in the season, or harvest the leaves right out of the container. Use the outer leaves only and the plant will continue to supply you with many more. (This is a great learning experience for a child. You could even add some radishes in another pot. It is a short experience and the fast growth keeps their attention focused on the plants. And the reward is something that they themselves will have added to a sandwich or their lunch!)

One of my salad favorites is the Super Gourmet Salad Blend from Territorial Seed Company (available at Pierson's). This packet of seed contains several types and colors of leaf lettuce and will keep you in salad greens for a whole year. The separate tastes make it an excellent salad base that you can't get at the supermarkets.

If you're not into gardening this time of year but would still like some home-grown greens, buy some alfalfa seeds at the Co-op or at Eureka Natural Foods and put a tablespoon of them in a jar with a lid that will allow water to drain out. Rinse them at least twice a day, and put them in bright light for a day or so to green them up. Harvest them when they are less than two inches long. Start a jar about every three days for a regular supply. They could be kept refrigerated for a short while but would still need to be rinsed daily.

Christmas Trees

If you wish to buy a living Christmas tree that can go into the garden after the holidays, shop early and pick one out at your nursery. The nurseries may carry Colorado blue spruce, dwarf Alberta spruce, Monterey or Aleppo pine and the giant sequoia. It is better to use these just outside the living-room window rather than inside where they may be endangered by warm, dry air. Some care is necessary to prevent a living tree from dying indoors. Keep them outside as long as possible. Water thoroughly. Hose it down, or better yet, spray the needles with an anti-transpirant. Set the tree in a container deep enough to permit watering of the root ball (but no standing water). Check the soil moisture daily. After the holidays, move it to a sheltered porch or carport and protect the root ball from freezing. Allow a week or so for the tree to adjust to the temperature change, and then plant as soon as possible.

Did I just say Giant Sequoia? They are very prevalent in this area, but before you plant one of them in your yard, pay attention to the warning on this page.

To prolong the freshness of a cut tree, saw an inch off the bottom of the trunk, then store the tree in a bucket of water in a shady area outdoors until you're ready to bring it indoors. Before setting the tree in a stand, saw another inch off the bottom of the trunk. Use a stand that holds water, and keep the reservoir full (check daily). Keep the tree away from heaters, and avoid hot-burning tree lights.


Keep cleaning up. Remove dead foliage and stems from dormant perennials. Pull up and compost garden refuse and rake up fallen leaves.

Fertilize all actively growing plants, including the winter annuals, with a high-nitrogen mixture. Cold temperatures, rain, and wet soil inhibit the uptake of nutrients, yet growing plants still need feeding.

DORMANT SPRAYING can be done during letups in the weather that allow the tree trunks and branches to dry off and stay dry for a couple of days. This spraying of the bark and branch surfaces will smother eggs and pupae, aphids, mites, and scale, and prevent many problems later in the season as these pests come out of their dormancy. See the nursery personnel for proper sprays and equipment for your needs. Spray the ground underneath the tree also.

Leave some broad hints for your soul mate or better yet, go to the store yourself and buy that special garden tool that you've looked at every time you went to town. Hey, it's Christmas, and who it deserves it better than you?

Next month! What do I do with that poinsettia? In the meantime, keep it in bright light but out of the sun and well away from heat sources. This gaudy tropical plant clashes with everything in sight, so stick it in a basket and add some long rosemary cuttings or conifer and eucalyptus branches, pine cones, holly, cotoneaster berries from along the get the idea.

Perfect Partners

You've probably wondered what to do with that small area in the yard that never gets the sun. Grasses are sun lovers and are just not suited to shaded areas. The local nurseries have flats of two tough ground covers that give an excellent foliage contrast in shady areas. These are Ajuga reptans (Carpet Bugle) and Pachysandra terminalis (Japanese Spurge). Both are available variegated and the Ajuga is grown in several different varieties and sizes. They will thrive in either full or dappled shade. The Ajuga has blue flower spikes in spring and summer and the Pachysandra has a white summer bloom. Plant them where there will be no standing water. They would like to be watered twice a month and fertilized once in the spring and again in the summer. Mow or trim off old flower spikes. They are not invasive and make a great transition between a walk and a shrub border. Try not to walk on them, but if somebody does, they will usually repair themselves quickly.

Sun angles for December

December sun passage, click to enlargeEnlarge image

During December, at a latitude of 40° north and at solar noon, a board fence six and a half feet high will cast a shadow that is over thirteen feet long to the north, more so during the the rest of the day. The sun's altitude (elevation) will peak at approximately 26°, or only a little over one-quarter of the way up the southern sky. This is the lowest position the sun will be in the sky.