The care information provided in this section represents the kind of practical advice is available for all the plants in this web site if you subscribe to the monthly customized newsletter Yardener’s Advisor.
| Monthly Tasks | |
|---|---|
| Month of January | Cosmos – No tasks this month |
| Month of February | Cosmos – No tasks this month |
| Month of March | Cosmos –Cosmos are easy to grow from seed, either indoors under lights or outdoors in the garden. If direct seeding is your choice for Cosmos, sow seeds indoors about 4 weeks before last frost, or directly into the garden bed after all danger of spring frost is past. |
| Month of April | Cosmos - Plant Cosmos seedlings purchased at the garden center or nursery, or those you've started indoors, as soon as danger of frost is past and the soil is warm (when night time temperatures stay above 50 degrees). Dig holes large enough to accommodate the root systems of transplants and set them so that the tops of soilballs are slightly deeper than the surround ground. New roots can form from the lower part of the stem which also help support leggy plants. Space plants about one foot apart. |
| Month of May | Cosmos – If Cosmos are growing in good soil containing lots of organic material, they need no fertilizer. In poor soils use one half tablespoon of slow-release granular fertilizer per plant. That is all you need for the season. |
| Optional task – Cosmos grow best when mulched. As soon as the Cosmos seedlings are tall enough, spread a 2 or 3 inch layer of some organic material such as chopped leaves, dried grass or wood chips on the soil around the plants. | |
| Optional task – Although these plants may need staking, they are difficult to stake. Save yourself the trouble of staking by planting them in a sheltered location or against a fence. If staking can’t be avoided, push twiggy branches into the ground when the plants are young and allow them to grow up between the branches to provide support. The branches will be hidden by the mature plants. | |
| Month of June | Cosmos – Cosmos will bloom from June through September with blooms that are red, rose, magenta, white, or bicolor. Overfertilizing and overwatering can reduce the number of flowers produced. |
| Optional - Cosmos may need support to protect them against heavy rain, wind and passers-by. Choose unobtrusive green stakes available at garden centers or find straight, sturdy sticks that are at least as tall as the eventual height of the Cosmos plants. | |
| Month of July | Cosmos – Both Painted Lady (Cosmopolitan) and Monarch butterflies visit Cosmos. |
| Optional - Cosmos benefit from deadheading and pinching back. Cut flowers frequently or pinch back center stems periodically to maintain compactness of the plant. | |
| Month of August | Cosmos – Cosmos are drought tolerant but you may want to water Cosmos during prolonged dry spells. |
| Month of September | Cosmos – To encourage reseeding, leave some flowers at season’s end, and do not disturb the soil over the winter. Your plants will die with the first hard frost. Remove them to the compost pile but keep the beds mulched right through the winter, ready for next year’s plants. |
| Month of October | Cosmos – No tasks this month |
| Month of November | Cosmos – No tasks this month |
| Month of December | Cosmos – No tasks this month |
