The Colorful Self-Seeding Fall Flower That Will Regrow By Itself In The Spring

Imagine a flowering annual plant that not only needs virtually no care, but also does next spring's seeding for you, so you have multitudes of spring blooms with almost no effort. This scenario is no fantasy with plants in the Cosmos genus. Of the 25-plus cosmos species, the most commonly grown cosmos, Cosmos bipinnatus, is a cheerful garden favorite with red, pink, purple, or white flowers. Sulfur cosmos (Cosmos sulphureus), with its yellow, orange, or red flowers is also popular. Cosmos flowers are wonderful for cutting, and pollinators flock to them. While robust in its self-seeding, cosmos is not invasive.

Among the easy-care attributes of cosmos is a high level of drought tolerance. Cosmos flowers thrive in garden containers if you follow the simple gardening tip to avoid over-watering and over-fertilization. In fact, some experts advise against fertilization overall. Cosmos tolerates—and sometimes even prefers—poor soil. Problem, pests, and diseases are minimal for cosmos.

Cosmos flower seeds are quick and easy to grow, even for beginner gardeners. Start spring planting after the last frost date, lightly covering seeds with up to a quarter-inch of moist, well-drained soil in full to partial sun. You can expect seeds to germinate in about two weeks and blooms to appear in seven weeks. Cosmos grows to be a tall plant—as tall as 4 feet—that can become top-heavy and keel over. Support it by planting densely so it can lean on its companions. Bonus: Dense planting will help suppress weeds. Once cosmos blooms, you can keep flowers going by deadheading into the fall, but if your goal is let cosmos re-seed itself, keep in mind deadheading may reduce seed production.

To take advantage of the re-seeding properties of this springtime garden favorite you can prep for in the fall, be sure cosmos is planted in an area large enough for it to spread through self-seeding. Watch for plentiful dried seeds around late summer and early fall, and then cut plants back to 12 to 18 inches tall. A month later, they will re-bloom. The cut-off seeds will drop to the ground and germinate in the soil to further enhance the cosmos portion of your garden. Harvesting the seeds is also an option, but consider letting the plant do the seeding work instead.