Cosmos Flowers – A Detailed Gardening Guide

cosmos flowers

Cosmos flowers, also known as cosmos bipinnatus or cosmos sulphureus, are popular annual flowers that bloom in a variety of colors and sizes including white, pink, purple, and red. The name “cosmos” comes from the Greek word “kosmos” which means “order” or “beautiful.”

They are native to Mexico and were introduced to Europe in the late 18th century. Cosmos flowers are part of the Asteraceae family and are also known as Mexican aster or simply cosmos.

They are known for their daisy-like flowers and delicate foliage. Cosmos flowers have a long blooming period, usually from mid-summer to early fall, and attract bees, butterflies, and other pollinators to your garden. Cosmos are also known for attracting butterflies and other pollinators, making them a great addition to any garden.

Grow & Care

Cosmos are part of the Asteraceae family and are related to daisies and sunflowers. cosmos flowers are easy-to-grow annuals that can provide a pop of color to any garden or landscape. Here are some tips on how to grow and care for cosmos flowers


Cosmos flowers are sun-loving plants that require at least six hours of direct sunlight per day to thrive. They can be grown in full sun to partial shade, but will produce the most blooms and have the best growth in full sun. In fact, if they don’t get enough sunlight, they may become leggy and produce fewer flowers.


Before you plant cosmos, you’ll need to choose the right spot in your garden. Cosmos prefer full sun and well-drained soil. They can tolerate some shade, but they won’t grow as tall or produce as many flowers. To prepare the soil, remove any weeds or debris from the planting area.

Cosmos prefer soil that is slightly acidic to neutral, with a pH of 6.0 to 7.0. You can add compost or other organic matter to the soil to improve its texture and fertility.

pink cosmos flowers
Pink cosmos flowers


The best time to plant cosmos is in the spring, after the last frost has passed. You can also plant cosmos in the fall, but they may not flower as well in the cooler temperatures.

Cosmos can be grown from seeds or seedlings. To plant cosmos seeds, scatter them on the soil surface and cover lightly with soil. Water gently to avoid washing away the seeds. Cosmos seeds usually germinate in 7-21 days.

If starting from seedlings, transplant them after the last frost date. Dig a hole slightly larger than the root ball of the seedling, and plant it at the same depth it was in its original container. Water thoroughly after planting.

Space cosmos plants about 12-18 inches apart to allow for good air circulation. Once your cosmos are planted, you’ll need to take care of them to ensure they grow healthy and strong.


Cosmos prefer soil that is moist but not waterlogged. Water them deeply once a week, or more often if the weather is hot and dry. If you’re growing cosmos in containers, make sure to water them more frequently.


Cosmos plants do not require a lot of fertilization. However, a balanced fertilizer can be applied once a month to promote healthy growth and blooms.


If your cosmos are getting too tall or leggy, you can pinch them back to promote bushier growth. Pinch back the stem tips when the plants are about 12 inches tall, and continue to pinch them back throughout the growing season.


Deadheading is the process of removing spent flowers to promote more blooms. Remove the dead flowers as soon as they start to fade to encourage the plant to produce more flowers.


If your cosmos are tall or top-heavy, you may need to stake them to prevent them from falling over. Use a bamboo stake or other support to prop up the plant, and tie it gently to the stake with a piece of twine.


Cosmos flowers can be harvested when they are fully open but before they begin to wilt. Cut the flowers early in the morning when they are at their freshest. Use sharp scissors or pruning shears to cut the stem just above a leaf node.


Cosmos flowers are annual plants that are typically grown as summer or fall bloomers and do not survive the winter in most climates. However, it is possible to overwinter cosmos plants in warmer regions with mild winters or by growing them indoors as houseplants.

To overwinter cosmos plants outdoors, it is important to prepare them for winter by cutting them back to about six inches above the ground and covering the base of the plant with a thick layer of mulch. In areas with mild winters, this may be enough to protect the plants from freezing temperatures.

In colder climates, it may be necessary to dig up the plants and store them in a cool, dry place until the following spring.

Pests and Disease

Cosmos are generally not prone to pests and diseases, but they can occasionally be affected by aphids, spider mites, or powdery mildew. To prevent these problems, make sure your plants are well-watered and well-fed, and keep the garden free of debris and weeds.

If you do notice pests or diseases on your cosmos, you can treat them with insecticidal soap or a fungicide. Make sure to follow the instructions on the label carefully to avoid damaging the plants.

Types of Cosmos

There are two main varieties of cosmos flowers: cosmos bipinnatus and cosmos sulphureus. Here are some details about each type:

Cosmos bipinnatus

This is the most common type of cosmos, and it is native to Mexico. It is an annual plant that typically grows to 3-6 feet tall and 2-4 feet wide. The flowers of Cosmos bipinnatus can be single or double and come in shades of pink, white, and crimson. The leaves are feathery and fern-like, and the plant blooms from mid-summer to fall. Some popular cultivars of Cosmos bipinnatus include the ‘Sensation’ series, ‘Candy Stripe’, and ‘Purity’.

cosmos bipinnatus
Cosmos bipinnatus Source: sprklg

Cosmos sulphureus

This type of cosmos is native to North and South America and is also an annual plant. It typically grows to 2-4 feet tall and 1-2 feet wide. The flowers of Cosmos sulphureus are smaller than those of Cosmos bipinnatus and come in shades of yellow, orange, and red. The leaves are also more narrow and less feathery. Cosmos sulphureus blooms from mid-summer to fall, and some popular cultivars include ‘Bright Lights’, ‘Klondyke Mix’, and ‘Sulphur Cosmos’.

Cosmos sulphureus
Cosmos sulphureus

Both types of cosmos are easy to grow and are popular for their colorful, daisy-like flowers. They are often used in borders, cottage gardens, and wildflower meadows, and make great cut flowers.

Companion Plants

Cosmos is a versatile plant that can be used for companion planting in vegetable and flower gardens. Here are some of the plants that make good companion plants for cosmos:


Cosmos attracts pollinators such as bees and butterflies, which can help increase tomato yields. In return, tomatoes provide shade for cosmos during hot summer months.

Tomato plant


Like tomatoes, peppers benefit from increased pollination provided by cosmos. Additionally, cosmos can help shade young pepper plants and protect them from excessive heat.



Cosmos can help attract beneficial insects that prey on bean pests, such as aphids and spider mites. Beans also fix nitrogen in the soil, which can benefit cosmos.


Cosmos and zinnias make a colorful and complementary pairing in the garden. Both plants attract pollinators and can help repel pests such as Japanese beetles.


Marigolds have been shown to repel harmful nematodes in the soil, which can benefit the growth of cosmos. Additionally, both plants attract pollinators and provide a bright burst of color in the garden.

When planting cosmos as a companion plant, be sure to provide adequate spacing between plants to allow for proper growth and airflow. Additionally, avoid planting cosmos near plants that require a lot of moisture, as cosmos prefers well-draining soil and can be sensitive to overwatering.

Medical Usage

While cosmos flowers have a long history of traditional medicinal use in Mexican cultures, there is currently limited scientific research on their medical properties. However, some preliminary studies have suggested potential health benefits associated with cosmo flower extracts. Here are some medical facts about cosmo flowers:


Cosmos flowers contain compounds with antioxidant properties, which can help protect the body from damage caused by free radicals.


Some studies have suggested that extracts from cosmos flowers may have anti-inflammatory effects, which could make them useful in the treatment of inflammatory conditions such as arthritis.

Preventing/Curing Cancer

A few studies have investigated the potential anti-cancer effects of cosmo flower extracts, with promising results. However, further research is needed to determine their efficacy and safety.

Hypoglemic Effects

Cosmos flower extracts have been shown to have hypoglycemic effects in animal studies, which suggests potential benefits for people with diabetes. However, more research is needed to confirm these findings.

Dermatological Benefits

Cosmo flower extracts have been shown to have antimicrobial and wound-healing properties, which could make them useful in the treatment of skin conditions such as acne and wounds.

It’s worth noting that while these potential health benefits are promising, more research is needed to confirm their efficacy and safety in humans.

Meaning and Symbolism

Cosmos flowers are known for their delicate beauty and come in a range of colors, including white, pink, and purple. These flowers have significant symbolism, and they represent different things depending on the culture and context.

They are generally seen as symbols of peace, harmony, beauty, love and affection. Whether given as a gift or used in a spiritual or cultural context, cosmos flowers are a meaningful and versatile symbol that can bring joy and serenity to those who receive them.


Cosmos flowers are easy to grow and care for, and add beauty to any garden. Choosing a sunny site with well-draining soil, planting in the spring, and providing regular water and fertilizer will help ensure a successful harvest.

Deadheading, pinching back, staking, and dealing with pests and diseases are also important for maintaining healthy plants. With these tips, you can grow beautiful cosmos flowers in your garden.

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