Try a Darwinian garden—let annuals seed themselves in the fall

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Last Updated: 
October 31, 2008

CORVALLIS – By letting nature take its course, you can let nature sow next year’s annuals, in a "Darwinian" garden.

Instead of planting flowers every spring, you can let some of your annuals go to seed each fall, explained Barb Fick, Oregon State University Extension horticulturist.

Self-sown seedlings will come up in the fall or early spring, when and where they are best suited to grow. Then, you can thin these annual flower seedlings to allow survival of the fittest and to sculpt the lines of color in your garden.

In other words, planting where you want flowers, you can thin out where you don’t want them. Let serendipity play a role.

Sweet peas, sunflowers, calendula, nasturtiums and annual delphiniums make perennial appearances in Oregon gardens. Bread seed and Shirley poppies, Clarkia, alyssum, even petunias will come back year-to-year, depending on winter’s severity.

Herbs and greens such as lettuce are also willing self-sowers. Dill, fennel, and cilantro may come back every year from seed heads left to over-winter.

Annual plants are programmed by nature to set seed in one year. Most of the summer we deadhead and fertilize annuals to keep them blooming and to postpone seed development.

But come September, try the Darwinian approach, by letting meticulous care go. Allow a few of your annuals go to seed. Let the flower heads dry and droop. The wind, the birds and the plants themselves will scatter ripe seeds.

Some cultivars will not come back the following year “true to type” because hybrids do not produce uniform offspring. For most people, that isn’t really a problem. It just means instead of having a pure stand of all white alyssum, you may end up with some splashes of purple. That’s serendipity.

Author: Carol Savonen, Peg Herring
Source: Barb Fick