Napa County
Newspaper Articles  Planting Wildflowers

by David Alosi, U. C. Master Gardener 

In gardens large and small, our California native wildflowers can put on an extended and colorful show that will also attract many butterflies and birds. Golden poppies, showy lupines, delicate gilias and late-blooming godetias and clarkias will create months of color in your landscape. Many wildflower species such as godetias and clarkias also make great cut flowers.

The best time to plant wildflower seeds is in mid-autumn, just before the first rains or during the earliest part of the rainy season but before the weather turns cold. Depending on weather, these easy-to-grow plants can begin flowering in February and last into July. If conditions are right, the plants may self-sow and come back for years. Alternatively, you can treat the area as an annual border and reseed it every year.

WIldflower seeds are available in local nurseries now. Some carry larger packages and some, such as Whitings Nursery in St. Helena, sell seeds in bulk. Many mail-order nurseries also sell various mixes in bulk. One source is Harmony Farm Supply ( in Sebastopol. The company has a Native California Wildflower Seed Mix and also sells several individual species by the ounce or pound.

Another local company that carries both a native mix and bulk seed is the Wildflower Seed Company of Napa Valley ( in St. Helena. The company will also make custom mixes in large quantities

Avoid seed mixes containing non-native species or mixes not designed for California. Some of these may come from areas of the country that receive summer rain or contain seeds of species that can become invasive in our area. Typical native mixes include

arroyo lupine, California poppy, five-spot, baby-blue-eyes, perennial flax, Chinese houses, gilia, bird's eyes, California bluebell, satin flower, godetia, fiddleneck and tidy tips.

One ounce of seed should cover 150 to 200 square feet. A pound can cover 1,000 to 3,000 square feet. You can cover an acre with 7 to 20 pounds, depending on variety. The Harmony Farm Supply catalog or the Wildflower Seed Company web site can help you determine the amount you need.

Good site preparation will help ensure success. Choose a site on the edge of the garden that needs little or no summer water. Cultivate the area and water well to encourage any weed seeds to sprout. Then cultivate again to destroy the weeds. Repeat as many times as possible before the first rain arrives so that your wildflowers will have minimal weed competition. Even with this precaution, you can expect to see some winter weeds when the weather cools.

You can spread the seeds by hand or with a drop spreader like the ones used to spread fertilizer on lawns. Mixing the seeds with sand or even potting soil can help you spread them evenly. Use a product similar in weight and size to the seed mix at a ratio of four parts sand or soil to one part seed. Rake the area lightly with a dirt rake after spreading. Most seeds do not need to be planted deeply. In fact, many will fail to sprout if they are planted too deeply.

I usually prepare the area in September and then wait for the first storms to really wet the area, usually in October. I watch the weather forecasts and try to plant the seeds just ahead of the rain. Once nature has watered them, do not allow them to dry out. Have a back-up plan to water with sprinklers if rains are delayed after seeding. Once the rainy season is underway, you can stop watering and hope that we don't have a dry year.

If you recognize some undesirable plants in your meadow or border, you can hand weed easily in the wet soil when weather permits. Try to avoid walking in the area when it is muddy as this can destroy the soil structure.

If you want the wildflowers to reseed, try to get the weeds out and prevent them

from going to seed. They will only become worse in following seasons. Do not deadhead your wildflowers until they have dried up and produced seeds for the next year. Allow them to self sow, or you can collect the seeds and save them for the following year. If

possible, leave the planted area dry in the summer and the seeds will again sprout with the rain the following fall.

For all of your work, you will be rewarded with a long period of colorful flowers in the spring and possibly for years to come.

The Master Gardeners will have an information table at the California Native Plant Society plant sale at Skyline Park in Napa on October 1 and 2. Stop by and visit us while shopping for native plants for your garden. 

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