Cosmea 'Purity' Cosmos bipinnatus 'Purity'

👤 Non-toxic to humans
🐾 Non-toxic to pets
🌸 Blooming
🍪 Not edible
‍🌱 Easy-care


'Purity' is a tall annual to about 1.2m, with bright green, finely-divided, feathery foliage on branching, upright stems. Pure white, saucer-shaped flowers 8cm across, with a yellow button centre, are produced throughout the summer

Plant Info
Common Problems

About this plant

  • memoNames

    • Family


    • Synonyms

      Mexican Aster, Garden Cosmos, Wild Cosmos

    • Common names

      Cosmos bipinnatus 'Purity'.

  • infoCharacteristics

    • Life cycle


    • Foliage type


    • Color of leaves


    • Flower color


    • Height

      3-4 feet (91-122 cm)

    • Spread

      1-2 feet (30-61 cm)

    • Plant type


    • Hardiness zones


    • Native area



  • money-bagGeneral Benefits

    • Attractive to pollinators: Cosmos bipinnatus 'Purity' is known to attract bees, butterflies, and other beneficial insects, which are crucial for pollination in gardens and ecosystems.
    • Easy to grow: This plant is known for its ease of cultivation, making it an excellent choice for novice gardeners or those with limited gardening experience.
    • Drought-tolerant: Once established, Cosmos 'Purity' can tolerate periods of low water, making it suitable for xeriscaping and reducing the need for frequent watering.
    • Ornamental value: With its pure white flowers and delicate fern-like foliage, it provides aesthetic appeal and can be a beautiful addition to any garden design.
    • Low maintenance: This variety of cosmos generally requires minimal care, such as occasional deadheading to promote continued blooming.
    • Fast-growing: Cosmos 'Purity' grows quickly, allowing for a relatively short period from seeding to flowering, providing garden color in a shorter time.
    • Cut flower: The blossoms make excellent cut flowers due to their long stems and vibrant, lasting blooms, perfect for bouquets and floral arrangements.
    • Self-seeding: The plant can self-seed under the right conditions, providing the opportunity for new plants to grow the following season with minimal effort from the gardener.
    • Edible petals: The petals of Cosmos 'Purity' are edible and can be used as a decorative element in salads and desserts, adding a touch of elegance to culinary creations.
    • Beneficial for wildlife: It provides a source of nectar for pollinators and can serve as a habitat for beneficial insects within a garden ecosystem.

  • medicalMedical Properties

    This plant is not used for medical purposes.

  • windAir-purifying Qualities

    This plant is not specifically known for air purifying qualities.

  • leavesOther Uses

    • Photography subject: Cosmos flowers, with their elegant form and pure white petals, are a popular subject for photographers aiming to capture the beauty of nature.
    • Crafting natural dyes: The petals of Cosmos flowers can be used to create natural dyes for fabrics, offering a range of soft, pastel colors.
    • Educational tool: Teachers may use Cosmos flowers to demonstrate plant biology and life cycles to students in a classroom setting.
    • Companion planting: Gardeners plant Cosmos amongst vegetable crops to attract pollinators which can increase the yields of vegetable plants.
    • Art inspiration: Their striking appearance and variety make them an inspiring subject for painters and illustrators who focus on botanical themes.
    • Garden aesthetics: Cosmos are used to provide a simplistic and pure aesthetic to contemporary garden designs, particularly in monochrome themed gardens.
    • Floral arrangements: Fresh or dried, Cosmos flowers can be used to add an air of delicacy and elegance to floral arrangements and bouquets.
    • Creative writing prompts: The serene beauty of the Cosmos flower often serves as a muse for poets and writers seeking inspiration.
    • Thematic events: Due to their association with order and beauty, Cosmos are often chosen as a decorative element for weddings and other elegant events.
    • Seed crafts: Children and adults alike use the seeds of Cosmos for crafting activities, such as creating seed mosaics or art pieces.

Interesting Facts

  • bedFeng Shui

    The plant Cosmos is not used in Feng Shui practice.

  • aquariusZodiac Sign Compitability

    The plant Cosmos is not used in astrology practice.

  • spiralPlant Symbolism

    • Harmony - Cosmos bipinnatus 'Purity', often known as the Cosmos flower, embodies harmony due to its balanced and orderly petal arrangement.
    • Order - The radial symmetry of the flower represents a well-ordered universe and tranquility in life.
    • Peace - The 'Purity' variety, with its typically white flowers, signifies tranquility and peace, making it a popular choice in gardens designed to create a serene atmosphere.
    • Innocence - The 'Purity' suffix in its name and the white color of the flowers encapsulate the idea of innocence and cleanliness often associated with white blooms.
    • Beauty - With its elegant and simple form, the Cosmos flower is frequently associated with an appreciation for beauty, particularly the natural and uncomplicated.
    • Love - In flower language, Cosmos flowers can symbolize love that is walking on air, blithely affectionate and light-hearted.

Every 5-7 days
2500 - 10000 Lux
Not required
Spring-Early Summer
As needed
  • water dropWater

    Cosmos, commonly known as Cosmos 'Purity', requires consistent moisture but should not be overwatered. Water the plant at least once a week with about 1 gallon of water, ensuring the soil is moist but not soggy. During hot, dry periods, increase watering frequency to twice a week. Make sure to water at the base of the plant to avoid wetting the foliage which can lead to fungal diseases. Adjust the watering schedule based on rainfall and check the soil moisture regularly; it should be kept evenly moist, not waterlogged or bone dry.

  • sunLight

    Cosmos 'Purity' thrives in full sun conditions. The best spot for this plant is in an area where it can receive at least 6 to 8 hours of direct sunlight daily. Avoid planting it in areas that are too shaded, as insufficient light may lead to weak growth and fewer blooms. If you live in an extremely hot climate, providing light afternoon shade can help protect the plant from intense heat.

  • thermometerTemperature

    Cosmos 'Purity' flourishes in temperate conditions and is quite tolerant to a range of temperatures. It can survive minimum temperatures as low as 25 degrees Fahrenheit, though growth will be stunted. It performs best when the temperature is between 60 and 80 degrees Fahrenheit. Cosmos 'Purity' is not frost-hardy, and extreme cold will kill the plant.

  • scissorsPruning

    Pruning Cosmos 'Purity' encourages bushier growth and more blooms. Deadhead spent flowers regularly to promote continuous blooming throughout the growing season. Cut back the foliage by one-third in midsummer if the plant looks leggy to rejuvenate and encourage new growth. Pruning is best done on a dry day to prevent the spread of disease.

  • broomCleaning

    As needed

  • bambooSoil

    Cosmos, or Mexican Aster, thrives in a well-draining soil mix with a pH between 6.0 and 7.0. The best soil mix for 'Purity' should include garden soil, compost, and sand with a 2:1:1 ratio to ensure good drainage and fertility.

  • plantRepotting

    Mexican Asters typically do not require frequent repotting; repot them every 2-3 years or as necessary if they outgrow their containers.

  • water dropsHumidity & Misting

    Cosmos 'Purity', or Mexican Aster, prefers moderate humidity levels but is quite adaptable and can tolerate the humidity found in most home environments.

  • pinSuitable locations

    • Indoor

      Place in a sunny spot; keep soil moderately moist.

    • Outdoor

      Full sun, well-draining soil, protect from strong winds.

    • Hardiness zone

      2-11 USDA

  • circleLife cycle

    Cosmos 'Purity', also known as garden cosmos, begins its life cycle when seeds are sown in early spring after the last frost or started indoors several weeks before the last frost to extend blooming. The seeds germinate within 7-10 days in warm, moist soil, developing into seedlings with true leaves. As the plant matures, it develops a strong stem and finely divided, feathery leaves characteristic of Cosmos bipinnatus. Flowering typically occurs in summer to fall, with the 'Purity' variety boasting large, snowy white flowers that attract pollinators like bees and butterflies. Once pollinated, the flowers produce seeds that can be collected at the end of the blooming season when the petals have fallen and the seed heads have dried. The plant completes its life cycle when it dies back after frosts in autumn, though it can reseed itself for the following season if seeds fall to the ground.

  • sproutPropogation

    • Propogation time

      Spring-Early Summer

    • Cosmos, specifically the Cosmos bipinnatus 'Purity', is often propagated through seed. The most popular method of propagation for this plant is sowing seeds directly into the garden soil. The best time to sow Cosmos seeds is after the last frost when the soil has warmed, typically in late spring or early summer. Spread the seeds thinly over the soil, and lightly cover them with about 1/8 inch (around 3 mm) of soil, as they need light to germinate effectively. Keep the soil moist but not waterlogged, and in 7-10 days, seedlings should appear. Once the seedlings have a couple of sets of true leaves, thin them to stand about 12 to 18 inches (30 to 45 cm) apart to allow for proper airflow and growth as they mature.