Cosmos are more than just a pretty face - they have range! Their crepe paper-like petals can take on a wide range of colors, all surrounding a vibrant eye that swirls like the galaxies. You can call them Cosmos, garden cosmos, or Mexican asters, but they are all species C. bipinnatus of the Asteraceae family. As a tender annual, they enjoy warm summer temperatures.

Once unboxed, you will want to harden off and transplant your plugs as soon as possible. Fast-growing Cosmos will become rootbound very quickly if they are left in the plug tray they were shipped in. If you aren't ready to plant them in their true home, bump up the plugs into larger trays or small pots to prevent root binding. Cosmos are suitable for most zones, but must be planted in the springtime after all danger of frost has passed. They simply cannot tolerate freezing at any point in the growth cycle, but can handle the heat of summertime and will thrive in almost all zones. As a short day plant, flowering is triggered when the days begin to get shorter in the summertime. If the plants are stressed by drought conditons or becoming rootbound, they will flower prematurely on short stems. The best kind of soil for Cosmos is loose, well-draining, and of low fertility. Too much nutrient content in the soil will cause lots of foliage growth, but very few flowers.

Plant Cosmos plugs 9 to 12 inches apart, and water them in well upon transplant. Plug roots are small, and they cannot reach for water from drip irrigation. Overhead watering with a hose or sprinker ensures they receive the hydration they need to establish in their bed and thrive. Once the plants are about 6 inches tall, pinch them down to a few sets of leaves to encouage branching. Pinching will give you more flowers! If the plants try to flower prematurely on short stems, keep pinching the buds and flowers until stems lengthen. Though time to bloom will depend on weather and temperature, you can expect flowers to appear about 45-60 days after transplanting plugs. Long stretches of high humidity can lead to powdery mildew and bacterial wilt; while common pests of Cosmos include Japanese beetles, thrips, and aphids. Applications of beneficial insects will help keep the ecology balanced in your garden.

As a cut flower, Cosmos should be harvested when the blooms are just starting to open. If the flowers are allowed to fully open, bees will pollinate them and the vase life of the cut stems will be dramaticallly decreased. Cut your stems with barely-opened flowers and the mature side buds will open in the vase. Place your cuts in cool water immediatley; if a floral conditioner like FloraLife is added to the water, you can expect a vase life of just under a week. If you'd like continued blooms, keep up with harvesting. Once the plant sets seed, it will shut down flowering for the season.