It's every gardener's fantasy: sunshine on demand and plants that take care of themselves. Though you can't do anything about the weather, you can fill your garden with "volunteer" flowers that will give you years of color with little effort. The miracle plants in question are mostly annuals that have a long flowering season and die by the end of the summer. Before they bite the dirt, so to speak, they produce seeds that fall to the ground and take root. Come spring, your garden is graced with a bouquet of new flowers and you haven't had to lift a finger.

Because you can never be sure exactly where these seeds will end up, volunteer gardens often have a spontaneous, exuberant quality. You can control the tendency toward chaos by paying attention to the shape of a plant before you introduce it into your garden. A low, mounding bloomer like viola is lovely near the border of a flower bed. Taller plants with lots of dense foliage, such as cleome, are best placed toward the back, where they won't block other flowers. And if an airy tall verbena pops up between the cracks in the patio's paving stones, you can enjoy it as an example of whimsical design or remove it to the compost heap.

Getting Started

The fastest way to start a volunteer garden is to purchase seedlings or small plants from a garden center. (Sowing your own seeds is cheaper, but not by much.) There are plenty of shapes and colors to choose from, but since self-seeding varies depending on location, check with a neighborhood gardener or your local nursery for tips on which volunteers do best in your area. Once you've made your choices, keep the following strategies in mind.

Plant in the right spot.
Most of these plants prefer full sun, which means at least five hours at midday. Some can take partial shade, about three to five hours of intermittent sun.

Condition the soil.
Dig organic matter such as compost into the soil to a depth of six inches in the areas where you plan to start your new plants.

Keep new plantings moist.
Plants will be less stressed and get a better start if you do your planting on a cloudy day or in the late afternoon. Water thoroughly once you position them. In the first weeks, keep the soil slightly moist by watering frequently. Once the plants are acclimated and growing, you can decrease your trips to the hose. Of course, make adjustments to your watering schedule depending on rainfall.

Deadhead.
Deadheading, or removing faded or dead flowers, prolongs bloom. Cutting stems for bouquets also encourages more flowers.

Allow seed heads to form.
When the blooming season is nearing its close, stop deadheading to let seed heads form. This step is essential to cultivating volunteers. After the seed heads dry, the seeds will plant themselves with the help of birds, wind, and rain. You can coax things along by removing the seed heads and shaking them around the areas where you want that flower to come up next year.

Thin seedlings.
Next spring let any mysterious seedlings grow until you learn to distinguish them from weeds. Once you know how to identify volunteers, you'll need to thin the crop. Begin by looking for the biggest and healthiest seedlings, then create enough space around them so they can grow and flourish. (It's tempting to let all healthy seedlings take root, but if some aren't sacrificed, none will grow.) After the seedlings are a few inches tall, thin further by transplanting some to a bare spot or sharing them with friends.