When to Plant Cosmos. Cosmos is a garden plant belonging to the family Asteraceae, containing about 40 species that are native to tropical America.
When to Plant Cosmos
They are grown before the first fall frost, between April- May. They will produce blossoms in June.
- Botanical Name: Cosmos bipinnatus
- Common Name: cosmos
- Family: Asteraceae
- Plant Type: Annual
- Native Range: Mexico, southern United States
- USDA Zone: 2 to 11
- Height: 1 to 4 feet
- Spread: 2 to 3 feet
- Planting Period: April- May
- Bloom Time: June to frost
- Flowers: Red, pink or white rays, yellow center
- Sun: Full sun
- Water: Medium
- Maintenance: Low maintenance
- Suggested Use: Annual, Naturalize
- Attracts: Butterflies
Time to Plant Cosmos
Cosmos seeds are sown between March and April to gain a healthy plant. They can’t abide by the frost, so avoid growing them in winters.
Some gardeners suggest planting the cosmos around May by providing them with an adequate amount of fertilizer to ensure the healthy growth of the plant.
- They can thrive in less rich soil.
- Require well-draining soil with full sunlight.
- Cosmos grow best in neutral to alkaline soils.
- Require warm, dry weather, even they are drought-tolerant.
Cosmos can reach up to 18 to 60 inches high.
How to Grow Cosmos Plant from Seeds
Maintain a space of 30 to 45 cm (12-15 inches) between each cosmos. It allows them to form a healthy bush.
Securing the Plant
In case of heavy winds, tie the plant to secure its branches. The wind will blow them up, causing damage to the plant.
Procedure for Growing Cosmos plants
- Take a small tray, fill it with soil containing compost to about 3mm deep.
- Sow seeds about 1/4-inch deep.
- Water the soil and cover it with a glass or polythene sheet.
- The seeds will feel the environment of a mini greenhouse and will help them germinate within a week.
- When the seedlings gain a height of a few inches, thin to 12–18 inches apart.
- Wait for about seven weeks.
- After seven weeks, the cosmos plant will produce beautiful blossoms.
- The blooming lasts till the first fall frost.
- Cosmos will be self-sowed throughout the garden if the spiky-brown seed heads are blown away during the fall.
It requires Regular Deadheading. After cutting the flowers, put them into a vase that contains adequate water. If you trim the flowers in the bud stage or are about to bloom, they will last for about 7 to 10 days.
- Stem canker
- Powdery mildew
- Gray mold
Recommended Cosmos Varieties
- Sea Shells
- Cosmos Sonata Series
Tall cosmos plants are the better choice for growing with perennials such as foxgloves, delphiniums, phlox, also with daisies, poppies, and asters.
The Dwarf cosmos, such as the Ladybird series, are great companions for zinnias, Johnny-jump-ups, pansies, alchemilla, or dark-blue morning glory.
Benefits of Cosmos Plant
- They act like magnets to attract bees, butterflies, and hummingbirds.
- They grow with ease with low maintenance.
- It’s the best choice to be grown in the garden to enhance the beauty.
- After planting cosmos, you get free seeds when the plant matures.
- Planting them is cost-effective.
- Cosmos possess self-sowing property.
- They produce Edible flowers.
- Pests seem to bother them at a low rate.
- You can use the cut flowers in a vase or gift them to your loved ones as a bouquet.
Cosmos is a garden plant belonging to the family Asteraceae, containing about 40 species that are native to tropical America.
They are grown before the first fall frost, in between April- May. They will produce blossoms in June.