Cosmos are a beautiful tall, annual plant for the garden which produce a multitude of blooms in many colours.
They prefer full sun and rich soil. Cosmos are the perfect plant for the back of the garden. Each year I grow these plants from seed that I have saved the previous year. They will also self seed and I will find surprise plants growing in various places of the garden.
Deadheading the flowers keeps them in continual bloom from July to first frost.
At the end of the growing season let the spent flowers go to seed. When dry you can harvest the seeds, let them dry, and store them for next year. I also leave some flower heads on the plant and the birds will enjoy the seeds. The goldfinches love the seedheads and will be there quickly to eat them up.
Plant seeds outside after the last frost or inside about 3 to 4 weeks before outside planting.
Cover with about 1/4 inch of soil.
The seedlings transplant easily so you can start them in pots and then pick the spot in your garden. Seeds germinate in 5 to 10 days. I use an old fork to lift and separate the seedlings. I usually try to transplant them after a watering or a rain.
Last year I grew some gorgeous orange cosmos and collected the seed. I’m hoping for some more of these gorgeous blooms this year.
If you are a seed collector you can print a seed packet or seed label to swap your seeds in.