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Growing Cosmos Flowers

About Cosmos: Pretty, Showy Low Maintenance Blooms

by Frances Santos

How To Grow Cosmos FlowersPretty, charming flowers that do not require much care – cosmos flowers are a perfect choice even for gardener hopefuls that aren’t as experienced with the green thumb. In fact, they are some of the easiest annual plants to grow, and bloom profusely even with poor soil conditions.

Because of this, beginner and master gardeners love growing them in the garden. This popular ornamental plant is native some areas in Mexico, South America, and Central America.

It is a fast-growing herbaceous plant that can grow up to 4-5 feet tall. Its flower has yellow disc florets at the center and a ring of single or double petals that come in rich colors of pink, yellow, red and white. These cheery blooms attract pollinators, making them an ideal choice for butterfly garden, bird garden, wild flower garden, and as companion plants for vegetables in an organic garden.

Dwarf varieties are great for small pots. Standard varieties are about 4-5 feet tall so when arranging plants in your garden, plant standard cosmos at the back of the borders.

These will create more drama. Cosmos flowers have long stem so they make wonderful cut flowers.

Happy cosmos bloom profusely. Since they self-seed, you can enjoy a picturesque explosion of blooms between June and October of each year.

Cosmos Propagation

Cosmos plants are propagated by seed. They have big seeds so they are easy to plant. Most cosmos are annuals. The perennial varieties may be propagated by division because these are Rhizomes. Regardless of the variety, cosmos seeds germinate quickly. They are usually sowed directly into the garden right before the last frost. But if you opt to start seeds indoors, you may do so.

Starting Seeds Outdoors

The seeds should be sown evenly over the surface of the soil or compost; spacing is about 12 inches apart. Overcrowding may cause the plants to slow up each other’s blooms. Cover the seeds lightly with compost. Take note of the date of sowing.

Next, water the seeds with great care using a mist sprayer fixed at the finest setting. Just spray the surface of the compost lightly about 4 inches away. Always remember not to overdo the watering process. The compost should not be saturated, or else the seed will rot and not germinate. When growing in containers, cover the pot or tray with a clear plastic or glass or use a propagator. Keep the tray or pot in the light but not in direct sunlight. Maintain a temperature of 68 to77 degrees Fahrenheit.

How to Grow Cosmos Flowers

Although Cosmos can do well even on average and poor soils and dry soil conditions, don’t deprive them of full sun—-they need it to bloom. If you want healthy, lavishly blooming Cosmos, find a good spot with moist and well-drained soil. Water the seedlings as necessary so they do not dry out.

If you started your seeds indoors, they can be transplanted separately to a 3-inch pot as long as the seedlings are capable of handling. Remember to be very careful when handling the seedlings. Never handle by their stems as this may cause injury and later on result to collapse of the seedlings. Handle each seedling gently by their leaves. Tease the roots of the seedling very carefully and make sure that not too many roots are damaged.

Fill each pot with good quality potting soil then carefully place the plant. Water the trays or pots very carefully using tap water. Harden off young Cosmos plants by placing them outdoors during the day. Once the seedlings are grown and hardened off, they can be planted outside as long as the last frost is over.

Caring for Cosmos Flowers

Cosmos plants are not fussy. It’s only major requirements are full sun and good drainage. For optimal growth, you may feed Cosmos plants with general purpose fertilizer once or twice per season. But do not over-fertilize them or they will produce more foliage and few blooms. Pinch plants if you prefer shorter plants and more flowers. Taller plants, especially those in large containers, may need staking for support. Windy or harsh weather may snap taller stems.

Cosmos Pests and Diseases

Powdery mildew is the major enemy of Cosmos. It is caused by crowded conditions or very damp environment. Aphids can be a threat to Cosmos if plants nearby are affected by infestation. It is also recommended to get rid of unwanted weeds but do not weed or cut plants during damp weather.