How to grow Cosmos flowers?

If you are looking out for a flower that will stay in bloom for many months and can be simply grown by scattering seeds, then the cosmos are a perfect choice. Cosmos flower is in vibrant colors red, yellow, orange, white and pink. These plants have a height of about 6 feet and they have ferny foliage of  very delicate texture. These flowers are ideal as decorations, used as cut flowers in arrangements and perfect for attracting the butterfly, hummingbirds and enticing beneficial insects in the garden. Cosmos is native to Mexico.

Common name: Garden Cosmos, Garden cosmos

Botanical name: Cosmos bipinnatus.

Varieties:

• Bright Lights: Orange, gold, and yellow mix with some semi-double flowers.
• Chocolate: Rich maroon color; available as plant starts only as seeds don’t come true to parent plant.
• Daydream: Pale blush with a crimson eye.
• Double Click: The fluffiest of the doubles, available in white, pink, and cherry shades.
• Seashells: Fluted petals make it an unusual addition to the vase.
• Sonata: Early to bloom and heavy flowering in pink, white, or scarlet.

Use in Landscape:

• Cosmos are an ideal addition to flower beds, borders, and containers.
• Shorter varieties of cosmos are perfect  to make the edging.
• Cosmos flower attracts many butterflies including monarch, painted ladies add these beauties to the butterfly garden.
• Use cosmos plants as backdrops in mixed flower borders.

Flowering season: They bloom starting from early summer until frost.

Growing Tips for Cosmos

Soil: Soil pH 6.0 to 6.8. is the best for these plants. However, owing to their ability to  sustain in adverse conditions as well, they can grow easily in poor soil too. Adding some organic matter to the soil will help them get the well-draining soil that they prefer.

Sunlight: For the best flowering, plant Cosmos in full sun. In very hot locations, consider planting Cosmos in areas where they receive some afternoon shade.

Water: Regularly, whenever topsoil turns dry. Keep the soil moist but not soggy. To avoid rot and fungal diseases due to over-watering.

Sowing season: Spring.

Sowing methods: You can sow them outdoors, however, in colder climates it's best that they grow indoors. Try to aim for a seed spacing of at least 2.5 cm and so at a depth of around 0.64 cm. Soil temperature should be kept higher than 20^oC to ensure good germination.

Harvest:

• Harvest flowers at any time after the plant’s bloom, but when it should be fully bloomed flowers.
• Put cut flowers in deep water immediately to prevent wilting.

Care:

• When  Cosmos finishes flowering, deadhead the plants by cutting off all of the dead flower blossoms. Deadheading will encourage the plant to produce more flowers and help the plant to fill out properly.
• Pinch off any extra stems or shoots growing up from the base of plants. This will also encourage stronger more vigorous growth
• Cosmos plants may require staking especially in exposed locations to keep them from falling over. Staking Cosmos provides some protection from strong winds.
• Water these regularly, but make sure you don't over-water the plants. Over-watering and over-fertilization can lead to plants with fewer flowers. Cosmos beds may become weedy due to the fact that they self-seed, so remember to check them.

Pests and Disease:

• Two of the most common fungal diseases of plants, Fusarium wilt and powdery mildew, can also plague cosmos plants.
  Fusarium wilt not only causes the plant to wilt but discolors the stems and foliage. The whole plant, unfortunately, is going to die and should be destroyed to avoid spreading the fungus.
• Powdery mildew spores float on the breeze and will attach to any host plant in shade. The fungus forms a powdery white coating over leaves, which will eventually cause foliage to yellow and drop off if left untreated. Plants with good ventilation, in bright light and that are watered in the day so foliage can dry are not as susceptible to fungal diseases of cosmos Aphids, including aster root aphids, spirea aphids and melon aphids, thrips and plant bugs are some common pests may infest cosmos plants. Aphids can spread fungi and viruses, thrips can scar leaves and flowers, and plant bugs suck juices from leaves, leaving them with a stippled appearance. Beneficial insects and other predators that are attracted to cosmos may be sufficient to control insect pests. Otherwise, use neem oil, insecticidal soap or petroleum-based insecticides to control these pests.