By Kathy Stoner, U. C. Master Gardener The often damp and dreary days of winter seem interminable, but they present opportunities to assess and plan for the spring and summer to come.
I had occasion recently to be in Southern California. I stayed in Redondo Beach, a coastal town a few miles south of Los Angeles International Airport. In front of my hotel, there was a tall hedge of pink Hibiscus rosa-sinensis, the classic tropical icon that adorns aloha shirts and beach bags. It was blooming. So were a lot of other plants.
This got me to thinking. Do these coastal L.A. County folks really like having no winter to speak of?
Granted, winter is a relative thing in a nation as climatically diverse as ours. You could argue that Napa Valley has no winter either if you are a Minnesotan.
How would I feel about having hibiscus blooming in my front yard in the middle of January? Do I really want to be a full-on, year-round gardener?
In my own garden I can see the dirt again, which, with my penchant for over planting, disappears from view for months at a time. I have no remorse; at least my dense plantings shade and crowd out most of the weeds, although a few desirable plants get lost in the melee.
When I do venture outside in winter, the infrastructure of the garden is exposed. Armed with a fresh sheet of graph paper and a stack of back issues of garden magazines (which are never under any circumstances disposed of), I can redesign my garden every winter and enjoy a brand new unfolding drama every spring.
Never really completed, my garden has become a dynamic work. Every year brings new plants, experiments, failures and triumphs. Seems to me we should be grateful for our clear seasonal delineation. Doesn't this make spring seem all the more precious?
Without the winter hiatus, how would those mounting house chores ever get done? When would we clean closets, re-arrange the cupboards, do touch-up paint jobs or eradicate cobwebs—all the stuff we postpone in spring, summer and fall when we'd rather be outside?
Many plants also need a winter hiatus—we call it dormancy—to perform well during the growing season. In particular, deciduous fruit and and nut trees drop their leaves in response to shortening day length and colder temperatures. They also produce hormonal growth inhibitors that protect the tree from sprouting tender new growth that would be damaged by the winter cold.
Cold temperatures in turn begin to break down these hormones over time. This is the process known as winter chill. Without the required number of chill hours (typically defined as hours during which temperatures are below 45ºF), the tree will not properly break dormancy and may not bear fruit.
Although the cumulative chill hours may be adequate during a given winter, prolonged periods of unseasonably warm days can diminish the benefits of chilling weather. For that reason, fruit-tree varieties with low chill requirements are better suited to mild climates like ours.
Some perennials, ornamental shrubs, seeds, bulbs and berries also require a period of cold. Although many gardeners consider a plant's hardiness, or cold tolerance, when shopping, those of us in the mild-winter West also need to think about the plant's cold needs.
In Napa County, we can grow a wonderfully diverse palette of plants. It's mild enough to push the envelope with cultivars that are considered sub-tropical, and yet we have enough cold weather to grow cherries, apples, peonies, hostas and many other plants that like a winter rest—none of which, incidentally, were planted around that hotel in Redondo Beach.
Every January while I am bundled up indoors during my own personal dormant season, I develop my Gardener's New Year's Resolutions. These are a lot easier to keep than character-building resolutions like going to the gym and flossing.
This year I will:
1. Not plant zucchini.
2. Take better care of my houseplants
3. Plant the French beans in successive sowings so I don't have 300 beans ready to eat on the same day.
4. Stake the delphiniums before they get six feet tall and snap off with the first big wind.
5. Just say no to petunias.
6. Plant 50 Oriental lilies.
7. Plant more herbs.
8. Plant more roses.
I put number eight on the list every year, and I always keep it.