Del Mar has a climate that is as close to paradise as one can get on this continent. Gardening in Del Mar can be a sublime pleasure or a frustrating challenge, depending on how well one understands our special climate and soils. This column will explore topics related to the challenges gardeners encounter, to help make the gardening experience enjoyable while making good use of our precious limited resources.
Our weather pattern is one of cool, wet, frost-free winters and warm dry summers. In an average year, Del Mar receives about 10” of rain, mostly between November and April….but there are very few average years! This year, an abnormally wet one, comes on the heels of two very dry years. Our temperatures are moderated by the Pacific Ocean. Winds from the west prevail about 90% of the time. An occasional Santa Ana wind blows from the desert during the fall and winter and brings hotter-than-normal temperatures. A similar climate is found in the countries surrounding the Mediterranean Sea, the southwest coast of Australia, coastal South Africa and Central Chile.
Our soils are severely deficient in organic material since native vegetation is scant and the drying sun shines incessantly; because of this, soils tend to be quite alkaline and not very water retentive.
So, how can we take advantage of our wonderful climate while, at the same time, minimizing water use and improving the soil?
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First, use plants native to California and other countries that share a Mediterranean climate. Educate yourselves by reading gardening books and magazines that are directed at gardeners in California; consider joining one of our local garden clubs or the San Diego Horticultural Society. There is a remarkable variety of plants that will grow happily here, but they may not be the varieties you grew up with in other parts of the country. Respect our rainfall pattern and expect most of the blooming to be in the spring. Summer is a time for dormancy!
Second, group plants with similar water requirements in the same beds. Since established trees, shrubs and perennials need only infrequent watering, thirsty varieties, including all annuals, are better off planted in pots.
Third, incorporate compost in the soil when you plant. Provide a finely-ground bark mulch under all plantings except ground covers to help retain moisture in the soil. Mulch will also keep the soil cool, discourage weeds, and add humus to the soil as it gradually breaks down.
Finally, install a sprinkler system on a timer and reset it seasonally to water as needed. The system should have enough zones to accommodate the differing needs of lawn, trees and shrubs.
The reward for taking the time to learn about how to garden in our special climate is a garden that will not require heavy maintenance….really! Future columns will focus on each of these issues in more detail.