Gardening

There are numerous challenges confronting the new gardener in the Bay Area. Firstly, the Bay Area has an unusual climate. It is one of five Mediterranean climates in the world—which include California, the Mediterranean Basin, Central Chile, South Western South Africa and parts of Southern and Western Australia.A Mediterranean climate is defined as a climate where more than 80% of rainfall occurs during the winter months—from November through March. There is usually minimal rain during a typical summer, June-September.

This means that most non-Mediterranean plants will require summer irrigation. As the population explodes and as water supplies become less reliable because of decreased run off and skimpier snow packs, conservation of water will become very important—particularly in the hotter regions. Gardeners are urged to limit the amount of high water-requiring plants such as lawns and to conserve water by means of drip irrigation systems and the construction of water tanks and underground cisterns which catch runoff. Another critical consideration is that many native plants—in particular the native oaks—will die if they are given summer water. It is a great temptation to plant beneath native oaks with moisture loving Rhododendrons and Azaleas because they are reminiscent of gardens in the Deep South. Doing so will cause you to lose your oaks.

Secondly, within the greater Bay Area, there are several distinct climate zones with wide variations of both temperature and rainfall—mostly predicated on the proximity to maritime influence and altitude. Areas close to the ocean and the bay are more temperate-warmer in winter and cooler in summer, receiving varying amounts of moisture-laden fog. In summer, the Central Valley heats up to over 90°F and moisture-laden air is drawn in through the 'Golden Gate.' Much of San Francisco and the Carmel-Monterey Area is blanketed by a cool fog preventing many plant species from thriving due to insufficient heat. Typically, the further south and east, e.g. San José and Livermore, have much lower rainfall ( less than 15") than Kentfield (more than 47") along with the hillier areas of Marin. There are large variations even within each zone. The Bay area has many 'micro climates' e.g., Bougainvillea will thrive in the Mission District in San Francisco but fail dismally along the Coast, even though the entire zone is zone 17.
read more...