Native Plant Alternatives to Cosmos bipinnatus (Garden Cosmos)

Cosmos bipinnatus, commonly known as garden cosmos or Mexican aster, is a medium-sized flowering herbaceous plant native to Mexico. The flowers are produced in a capitulum with a ring of broad ray florets and a center of disc florets. They come in various shades of pink and purple as well as white.

Cosmos bipinnatus is known to be a prolific self-seeder. This means that if you allow the flowers to go to seed, you can expect new plants to sprout up in the following year without any additional planting on your part.

After the plant flowers, it will produce seed heads. If these seeds are not collected, they will eventually dry out and drop onto the soil. When the conditions are right, these seeds can germinate and grow into new plants. This is a common trait in many annual and biennial plants, and is one of the ways these types of plants ensure their continued survival.

The ability to self-seed can make Cosmos bipinnatus an excellent low-maintenance choice for your garden. However, this trait also means that Cosmos can spread beyond its intended area in the garden.

Garden Cosmos is listed in the Invasive Plant Atlas of the United States.

According to the U.S Forest Service, Invasive species have contributed to the decline of 42% of U.S. endangered and threatened species and 18% of U.S. endangered or threatened species. Invasive species compete directly with native species for moisture, sunlight, nutrients, and space. They displace and alter native plant communities, degrade wildlife habitat and water quality, and potentially lead to increased soil erosion.

The federal government has estimated that nearly 25 percent of the 20,000 plant species native to North America are at risk of extinction, many of these through habitat loss. You can help reverse this trend by planting great native plants in your garden.

A plant is considered native if it occurs naturally in a particular region or ecosystem without human introduction. There are many benefits in growing native plants. First, these plants are better adapted to soils, moisture, and weather than exotic plants that evolved in other parts of the world. They need fewer fertilizers and pesticides or use less water. Second, they are unlikely to escape and become invasive, destroying natural habitats. Third, they support wildlife, providing shelter and food for native birds and insects, while exotic plants do not.