Basics - Know Your Climate and Work with It
Sun, Wind, Rain
Know your climate and work with it. A few years in one place should be enought to familiarize yourself with your local weather.
In general, California has a “Mediterranean” climate with a mild, rainy winter and a moderate to hot, dry summer. Our precipitation comes at just the opposite time from most of the world, and as a result, a great many of the world’s plants are not really at home here—most plants want their precipitation in the spring and summer when they are growing and a dry rest in the cold season when they are dormant. Even so, it is amazing how adaptable many of our Mediterranean garden plants can be—some will even do well enough without supplemental watering in summer. [Expand re precipitation]
The angle of the sun is lowest in winter. This is important for a number of reasons, for example:
- Take advantage of this by having south-facing windows on house and greenhouse to supply free heat, also avoid evergreen trees on south side—deciduous trees let the light through in winter.
- Contrary to “commonsense” or common “knowledge”, many tropical, subtropical, and desert plants with a southern exposure really suffer in the winter, when the low sun blasts any vertical stems directly and intensely at just the time the plants are least able to deal with it, i.e. when they are dormant; cacti and green-trunked trees are especially vulnerable-you might have noticed the south side of columnar cacti burned to a scary yellow or red in winter, while the shaded side is perfectly healthy looking. Therefore protect south side of such plants, or better, plant them where their south sides are not exposed. (You might be amazed how well citrus, etc. do in more-or-less shaded spots.)
No-tech tips for frost protection based on where to plant things (without using annoying or costly or work-requiring “extraordinary measures”).
Also regarding sun angle:
In frost-prone areas, avoid planting tender subtropicals on the east side of a building where they will be hit by the early morning sun. This is because the worst frost damage is caused by rapid thawing after the freeze. Better to plant them on the west side.
Also bare ground mound (especially on south side of) tender plants absorbs more heat, especially if on south-facing slope, than mulched or vegetated ground.
Wind:
Provencal farmers plant windbreaks at right angles to the Mistral. Hedgerows/windbreaks not only protect their leeward side, but actually halve the wind speed on windward side as well. But . . . dense isn’t necessarily better. Tall thickets of cypress block wind well, but produce returning currents behind them, just like skyscrapers do. Sparse windbreaks of poplar give three times the wind protection, even though they let some of the wind through.
Put doors and windows on sheltered side. Nothing is more pleasant than a warm, sheltered courtyard on a clear, cold, windy winter day.
Above all, look for “banana belt” microenvironments—best is about two-thirds of the way up a high hill, facing south.
Summer fog:
Most of coast (except southern California), especially in San Francisco/Monterey Bay areas or wherever there is a low “pass” between coast and Central Valley.
These fog-prone areas are also wind prone, and for the same reason, i.e. hot, rising air in the Central Valley sucking cool, moist air off the ocean—“The Great California Air Conditioner”.
Fog belt limits severely the number of plants that can be grown well, especially many of the heat-loving fruiting and flowering trees. On the other hand it is ideal for certain other plants, especially the “cloud-forest” plants, e.g. fuchsias, begonias, artichokes, brussel sprouts.
Other extremes are:
Hot-summer areas (Central Valley, other interior valleys)
Cold-winter areas (high elevation, interior north, deep canyons) lilacs, flowering cherries and other such, forsythia, alpine/rock gardens
Dry-winter areas (southern Central Valley, southern California, rainshadows) best for cactus gardens, etc.
Priorities:
If you are like most people, your choice of homesite is based more on economics and neighborhood and view than on what used to be the primary considerations: i.e. soil quality, access, water supply, and safety from flood and fire. Most people now do not choose their location because it is ideal for growing their favorite plants (bamboo, or cacti, or subtropical, or whatever); instead they grow whatever plants are suited to the place they have chosen on the basis of other considerations. Most of us don’t have the luxury of picking and choosing, no matter what our priorities may be.
