The mixed weather of June is over, and July and August in San Francisco are the months of fog, fog, and more fog. For gardeners, this means that just as gardens are really kicking into high gear in other parts of the country, and producing a year’s worth of warm season crops like corn, tomatoes, and melons, along with giant dahlias and roses, many San Francisco gardens have a letdown.
Soils dry out completely and our annual summer drought takes hold. Plant growth and bloom slows or stops. Leaves that were shiny with growth in May are suddenly tough and grey. Optimistically planted roses, dahlias, and squashes are covered with fuzzy mildew and black spots of fungus. Many favorite and familiar plants have evolved in climates where summer means warm, moist soil and warm, dry days between rainstorms. In the foggy neighborhoods of San Francisco, these poor dears find constantly cool, dry soil and cool, damp air. No wonder everyone is a little disappointed.
There are several strategies local gardeners use to prevent this letdown moment from making the garden painful to look at for the next few months. Some of these strategies can be implemented right now. Others require more planning and preparation, but they can be done this fall and next spring so that next year June won’t be the beginning of the end for your garden.
Time Shopping Trips
Most nurseries carry plants while they are in bloom, since this is when customers are likely to buy them. As a result, many home gardeners will plant one bed or area of the garden after a nursery shopping trip with plants which all bloom at the same time, often in spring. To create a reliable sequence of bloom in a bed or border, stagger your planting and shopping into three or four different sessions. Plant summer blooming perennials and shrubs now, when they are available in the nurseries and you can see the flower colors. Salvias, penstemons, many bright daisies, lantanas, and verbenas are blooming now and are appropriate plants for our dry, cool summers. In shady areas consider Plectrantus, species fuchsias, campanulas, foxgloves, and abutilons. Don’t forget to choose some things for foliage color and texture, such a ferns, grasses, Phormium, and Loropetalum. Leave spaces in the border for plants with winter and spring bloom. They will be available later on. You will need to water your summer-planted goodies this year on a regular basis to keep them healthy and colorful. But many of these plants will not need summer irrigation after a year in the ground.
With a long dry summer ahead, now would be a wonderful time to take the plunge and install drip irrigation in your garden if you haven’t already. Drip irrigation delivers water directly to the root zone of your plants in a slow steady application which soils can absorb best. It is a terrific water-saver in the long run, although it is certainly an expense when it is first installed. Plants that are watered deeply and less frequently develop tough, deep root systems that make them more resilient to our annual drought, and reduce water use in the long run. Classes are available at the Urban Farmer Store to help the home gardener with water-wise irrigation techniques.
Plants with similar soil and water needs should be grouped together in the garden. By creating a garden bed or area where drought tolerant plants are grouped together, you can reduce irrigation in future years. Many garden plantings are doomed because plants which prefer no summer water are planted among others which can’t survive without it. Unfortunately, in this situation some plants in the border will be looking unhealthy whether the gardener waters or not. (Don’t forget, all plants planted or transplanted this summer will need irrigation, whether or not they will be drought tolerant once their roots have had a chance to grow deeply into the soil.)
Climate Appropriate Plants
Our native flora, and plants from many similar climate zones around the world, have evolved through the millennia for exactly the conditions we can offer them in San Francisco gardens. These plants have their own strategies for dealing with dry summer soils and cool, damp air and winds. They come from climate zones known as Mediterranean, or maritime climates. These plants are the ones that are vigorous in fog city summers, continuing to look healthy when their neighbors from unsuitable climates begin to wilt and stress.
A clue to the origin of some seaside plants is the word “maritima” in their botanical name. Some of these are plants are blooming and looking good right now at Garden for the Environment at 7th Avenue and Lawton. See if you can find them in the drought-tolerant demonstration beds and borders. All these plants are drought-tolerant once established, and are healthy and free-blooming even with cool foggy and windy days.
Armeria maritima or sea thrift is a California native plant which is blooming now at GFE and also along the wild cliffs and seaside meadows of the California coast. A low groundcover, Armeria features clumps of short grassy green foliage topped with fuzzy pink balls of flowers. Armeria is neat looking all year and is a reliable addition to the foreground of a flowering border or rock garden.
Asteriscus maritimus or gold coin is a Mediterranean native that thrives in our very similar climate. Now its shiny mound of sturdy leaves is covered with bright and cheerful yellow daisies. If the faded flowers are trimmed off, it will continue blooming almost non-stop all year long.
In GFE’s exterior borders you can see several examples of Lavatera maritima bicolor, or tree mallow, a big unstoppable year-round bloomer that just loves our sandy soil and cool summer air. A Mediterranean plant, Lavatera maritima bicolor has been a signature plant in GFE’s borders since the garden was founded in 1990, and has been a tough, reliable performer year in and year out.
Gardening in a Parka
There are hundreds of plants which thrive in a Mediterranean climate, although they may not have “maritime” in their names. A little research at the nursery, the library, or on the internet will help you choose the plants that are right for your garden. By choosing plants suited to our maritime climate, grouping them wisely, watering them deeply but infrequently, and creating a robust sequence of bloom in the garden, you can begin to look forward to summer gardening in San Francisco, even if you have to wear a parka to do it!