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San Francisco's dahlia garden is in full bloom

September 18, 2010
Jane Scurich

Ready for an astonishing blast of vibrant color and breath-taking beauty? Plan to visit Dahlia Dell in San Francisco's Golden Gate Park, just east of the Conservatory of Flowers. Blazing with magnificent color to awaken your senses from this summer's persistent fog, this show will brighten your spirits and set you planning your own dazzling floral display for this time next year.

If you have never explored the Dahlia Dell, you're in for an amazing treat. Maintained by passionate volunteers, the Dahlia Dell features an assortment of dahlias of all sizes, shapes and colors, to captivate your heart.

Central to the Dell is a level tear-shaped bed; nearby is the terraced hillside, both dedicated to dahlias. The property belongs to San Francisco Park and Recreation Department, which provides water and rototilling. Close to 500 plants and their constant tending have been provided by the Dahlia Society of California (DSC) since the mid-1920s. The plants are all identified by easily readable name tags.

The dahlia is even the official flower of San Francisco. On Oct. 4, 1926, the San Francisco Board of Supervisors adopted a resolution that says because of its versatility, beauty and infinite variety of color and form, "it is the very symbol of San Francisco life and of the spirit of her people." The resolution also includes some delightfully flowering language comparing dahlias to "sophisticated world travelers" like those who return to San Francisco; you can read the proclamation in its entirety atwww.sfdahlia.org/aboutdsc/official_flower.htm.

While most written advice suggests dahlias require a minimum of six hours sunlight a day, the Dell proves there are exceptions to most any rule. I work five days a week in Golden Gate Park and I can assure you that six hours of sun is a rarity in the summer - particularly this one. However, the plants in Dahlia Dell are enthusiastically blooming. According to Deborah Deitz, corresponding secretary of DSC and a frequent volunteer in the Dell, this record cool summer has resulted in plants that are "a bit smaller than normal, but the colors are even more vibrant this year."

Dietz offered this valuable advice for growing dahlias:

- Plant in well-drained soil rich with compost and nutrients.

- Select genetically superior stock, bred for strength of stem, vibrancy of color and disease resistance.

- Water deeply and then wait for dahlias to slightly droop before re-drenching.

- Exclusively bottom water; no overhead watering.

Growing dahlias is relatively easy as they are resilient, attract few pests and are "deer resistant" - but not deer proof. They do not tolerate a hard freeze, but our temperate climate will not cause them damage, so they can overwinter in the garden. You will need to dig them up every few years and separate the multiplying tubers to share with friends or increase your supply.

I planted my first dahlia quite a few years ago and left the plant in the garden year after year, until one summer I noticed a mountain of tubers, forcing their way to the surface, begging to be divided and replanted; a not so subtle reminder from this hardy plant.

Dahlias are perennials grown from tuberous roots and are native to Mexico. Centuries of hybridizing has produced an amazing palette of riotous colors. Dahlia blooms are composed of miniature flowers known as florets that present themselves in 18 recognized forms from simple daisy-like blooms to tightly packed balls or pompoms.

There's a dahlia that will fit into almost every landscape, as plants range from 1 to 6 feet in height, with blooms 1 to 12 inches across. Colors include yellow, orange, pink, purple, scarlet and white, with multitudes of variations; most every color except blue is well represented.

Dahlia tubers will be available in garden centers after the winter holidays. You'll also find a fabulous variety at the annual San Francisco Flower and Garden Show, which is scheduled for March 23 through 27 at the San Francisco Expo Center.

The DSC has an annual sale on the first Saturday of April at the Hall of Flowers, at Ninth and Lincoln in Golden Gate Park. Members are available to share growing tips and advice on size, soil, nutrient and climate needs.

A feast for your eyes is waiting for you in Dahlia Dell. Prime viewing time is now through mid-October. It's a show you don't want to miss.

The University of California Marin Master Gardeners are sponsored by UC Cooperative Extension. For questions about gardening, plant pests or diseases, call 499-4204 from 9 a.m. to noon, and 1 to 4 p.m. weekdays, or bring in samples or pictures to 1682 Novato Blvd., Suite 150B, Novato.

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