How to Grow And Care For Cosmos Flower

Cosmos flowers are derived from the Greek word 'kosmos', meaning 'harmony'. The name was derived from the orderly placed petals of the cosmos flower. Cosmos plants are easy to grow and are sown in the spring. The plants reach their full maturity in about two months. 

Cosmos flowers are usually short-day plants. As the days shorten in summer, they start to bloom the most, comparatively there is no heavy bloom during the early summer. Cosmos continue to bloom till the first frost of fall. 

• Location and Time: Early spring is the time to sow cosmos seeds. Cosmos plants enjoy warmth and heat so choosing a sunny space for the plantation will work the best. In the absence of this, a slightly shady area will also work. 
• Soil Preparation: Cosmos do not demand high-quality soil. Set the plantation area clean, loosen the soil for increased circulation and also remove the weeds. Cosmos however do prefer well-drained soil. Soggy soil halts the growth process of the plant by damaging the roots. 
• Amending the Soil: Though Cosmos are not heavy feeders, adding some fertilizer to the soil won't hurt either! Use organic fertilizers like compost, well-rotted manure or aged leaf mold for the best results. A little goes a long way so don't overdo the fertilizer.

As the spring arrives and the soil starts warming up, it's time to begin Cosmos's planting. As these plants don't need fancy requirements, you can directly sow the seeds into the ground.

In the prepared soil, scatter the seeds and simply cover them with a thin layer of soil or compost. Make sure the seeds are not more than 1/8 inch below the surface. This is to make sure that the seeds grow effectively. 

Though it's not necessary to focus too much on thinning, it's important to note that the growing plant will require larger space. We recommend a plant spacing of 1 to 2 feet for creating a full backdrop. As too much spacing can result in tall and spindly plants.

Immediately after planting, start watering lightly to ensure the seeds are moist and reach the germinating stage easily. As you notice the seedlings emerging, which generally happens within 3 weeks, reduce the watering frequency allowing the soil to dry out slightly between waterings.  

Whenever the topsoil feels dry to touch, water deeply. This step typically takes 2-3 days. As the plants get established, they become more drought-tolerant. At this stage, you can water the plants once or twice a week. If your garden receives regular rainfall, you should be careful and wait for the time when topsoil dries out.

The organic fertilizer you used during the preparation process of the soil may be enough for Cosmos to grow, but you may put extra once the seedlings have been established. A light application of fertilizers with equal N-P-K is recommended for Cosmos. Fertilizers formulated for flowering annuals can be used as an alternative. 

For anyone who is not fond of chemical fertilizers, you can use organic fertilizers such as compost, aged manure or fish emulsion. These fertilizers are equally effective and gradually provide nutrients to the soil.

Talking about frequency, you can apply fertilizer once every 5 to 6 weeks during the growing season. Avoid direct contact with the foliage and over-fertilizing as both can hamper the plant's growth and flowering process.

Deadheading is the practice of removing spent flowers from your cosmos plants. In this process, faded flowers, unsightly wilted flowers and dead flower heads are removed from the plant to help redirect the plant's energy towards producing more fresh and flowers. 

For deadheading, simply pinch off the spent flower head with your fingers. You can also use sharp pruners or snips to cut the stem just below the wilted flower. If you focus on cutting just above a healthy set of leaves or a new bud, the new growth will develop fully. 

Schedule deadheading throughout the growing season. You can do this every few days or whenever you see flowers starting to fade.

Some varieties of cosmos can grow quite tall (some varieties reaching up to 8 feet). These varieties must be provided with stakes for support. Use bamboo canes, wooden dowels or other sturdy stakes for individual tall plants. To secure the support, you can loosely tie the stem to the stake with twine or garden string.

If there are multiple plants in a row, consider using a row support system. This can be a wire fence or a row of tall stakes connected with twine or wire. If your garden has fence, you can simply grow the cosmos plants near them for ease. 

You can also pinch out the growing tip of the main stem when the plants are young (around 6-8 inches tall). This directs plants toward branching and results to a plant that is sturdy.

For obtaining the full bloom, there are certain aspects that should be looked after. Here, we will talk about the support and care Cosmos plant needs before, during and after the plantation.

Pre-Planting Care

1. Cosmos is a sun-loving plant. So, choose a planting area that receives at least 6-8 hours of direct sunlight daily for proper full bloom.
2. Don't overfertilize the soil while amending. 

Planting Care

1. Don't sow seeds too deep. 
2. You can use mulches to make sure the cosmos plant grows well. Mulches like shredded bark, wood chips, compost, or chopped leaves will work better than plastic or fabric ones. Mulch will help the cosmos grow by retaining moisture in the soil, weed suppression, moderating soil temperature and adding organic matter to the soil.

Post-Planting Care 

1. Make sure to water regularly. Be more attentive to the watering schedule during dry spells.
2. Avoid excessive fertilization. In doing so, the plant will grow leggy with fewer flowers. 
3. Watch out for weeds regularly. Weeds compete with flowers for nutrition and moisture, this can be prevented by weeding on a regular basis. 
4.  For taller plants, staking can help prevent toppling. 

For all the cosmos flower gardeners, we have brought some useful tips that will help you get the maximum bloom throughout the summer. Read below and find the ones you haven't tried out before:

• Colorful Combinations: Cosmos come in many colors. From classic pinks and whites to vibrant oranges, reds, and yellows, just imagining the beautiful combinations in your garden can make you feel happy. So, this spring play around with color combinations to create stunning displays all over your garden and wait for them to bloom! 

If you prefer a monochromatic look, plant the varieties in various shades of the same color. For an eye-catching display, plant cosmos with flowers in opposite colors on the color wheel. For example: You can pair pink cosmos with blue salvia or orange cosmos with purple coneflowers.

• Pinching for Bushier Plants: Some varieties of Cosmos plants can go over 7 feet. For such plants, if you don't wish to have them that long, you can simply pinch out their growing tips. This allows the side branches to grow to optimum. 

As a result of pinching, the plants grow bushier and guess what the plant will flower in abundance. 

• Companion Planting: The wide colors of the flowers of Cosmos make them extremely attractive to pollinators. So, for gardeners who also plant vegetables like tomatoes, peppers and pumpkins, that need pollinators for pollination, you can plant these flowers in your garden for successful fruiting of the vegetables. 

Except pollinators, Cosmos plants also attract predatory wasps that help to control pests in your garden.

• Succession Sowing: If you want your garden to bloom with Cosmos flowers the whole summer, succession sowing is the key. The principle behind this technique is to sow Cosmos seeds little at a time. Yes, you heard it right! Spread the cosmos plant seeds every few weeks throughout spring and early summer. This will help extend your garden's blooming season and will make sure you have a continuous display of cosmos flowers throughout the summer.

Cosmos flowers are relatively less prone to pest infestations and more resistant to most of the common plant diseases. Still, they are not completely immune. Some of the pests and diseases that may affect the cosmos plants are listed below: 

Pests

• Aphids: Aphids are tiny, soft-bodied insects that suck sap from the leaves and stems of plants. 
• Thrips: Thrips are smaller than aphids and are often difficult to see with the naked eye.
• Japanese Beetles: Cosmos are one of the many plants that Japanese beetles love to feast on.
• Lygus Bugs: Lygus bugs, also called tarnished plant bugs, have piercing-sucking mouthparts that damage leaves and flowers.
• Leafhoppers: Leafhoppers feed on plant juices. While they don't cause damage on their own, they may transfer diseases like aster yellows to your cosmos plants.

Diseases

• Aster Yellows: As described above, aster yellow is transmitted by leafhoppers, tiny grasshopper-looking insects.
• Bacterial Wilt: This disease shows up as brown wilted stems that spread to the base. As a result, the whole plant gets infected.
• Powdery Mildew: This is a fungal disease in which the leaves of the plant is coated with a white powdery substance.
• Fusarium Wilt: This is also a fungal disease that causes wilting of the leaves; when severe leads to plant death.

The management of the above-mentioned pest-related infestations and other diseases is possible by following methods:

1. For pests, early detection is the key. 
2. Companion flowers such as marigolds can help pirate bugs that help to control the pest naturally. 
3. Spraying a strong jet of water and organic options like neem oil may also help.
4. As a last resort, you can use insecticides for severe infestations.
5. For mild fungal diseases like powdery mildew, improve air circulation to plants, water only at the base of the plant and in severe cases use organic fungicides like neem oil or sulfur.
6. There is no treatment for fusarium wilt. If there is pink fungal growth on roots, remove and destroy affected plants to prevent spreading.
7. As bacterial wilt also does not have treatment, remove nd destroy affected plants to prevent further spread.
8. For aster yellows, remove the affected parts only. 
9. If there is a history of diseases, plant the cosmos in a different place this time.