Mexican Aster Cosmos bipinnatus
Other Common Name(s):
- Phonetic Spelling
- KAHS-mos bye-pin-NAY-tus
- Description
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Introduced to the US as an ornamental flowering plant from Mexico or tropical America, tall Cosmos offers a variety of daisy-like maroon, pink, lavender, and white flowers on stalks that will get up to 4 feet tall. The word cosmos is derived from the Greek word for harmony, referring to its evenly placed petals. Although many cultivars and varieties are available, two annual species, Cosmos sulphureus (Yellow Cosmos) and Cosmos bipinnate are the most familiar to the public.
Plant cosmos in a location that receives at least a half-day of direct sunlight. Sow the seeds outdoors after the danger of frost is past and when the soil has warmed to at least 65 degrees. Rake seeds into a loose soil as planting seeds too deeply will hinder germination. Keep the soil moist for 5 to 10 days after seeding. Seeds will germinate in 7 to 21 days. Cosmos needs only basic care to provide an abundance of colorful blooms all summer. Taller varieties may need staking if subjected to high winds and frequent storms.
When the spring-planted cosmos appears to have an abundance of dried seed, do not remove the plants. Encourage re-bloom by cutting the plants back to 12 to 18 inches high. They will be back in bloom in a month and the seed that is cut off will fall to the ground, germinate in the hot soil, and increase the density of your plant population and the eventual bloom display.
Although non-invasive, it will aggressively self seed. Deadhead to prolong the flowering period.
In addition to the basic color choices, many variations are available in the form of hybrids. They are typically pastel.
Insects, Diseases, and Other Plant Problems: Stem canker, powdery mildew, and gray mold are common issues. Insects include aphids, Aster Leafhopper and the Gray Looper Moth.
They may require staking due to their height. Protect from strong winds. Overwatering or overfertilizing can lead to plants with fewer blooms.
To prevent self seeding, remove the spent blooms before the seed spreads.
- See this plant in the following landscape:
- Cultivars / Varieties:
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- 'Antiquity'
1-2'. flowers early, 2" flowers. - 'Candy Stripe' Mix
White flowers with stripes along the length of the petals - 'Chocolate'
Uncommon variety, chocolate scented, deep maroon flowers - 'Cosmic' Series
1' tall with yellow or orange flowers. - 'Daydream'
Pale pink flowers, darker pink towards the center. - 'Early Wonder'
White or pink flowers. - 'Gazebo' Mix
White, pink and red flowers. 3-4' in height. - 'Picotee'
White flowers with reddish-pink edges, light red lines running the length ft the petals, yellow centers. - 'Psyche Mix'
4-5' tall, lavender-pink or white flowers. - 'Purity'
White flower - 'Seashells' Mix
Trumpet-like flowers, petals rolled into tubes. Red, pink and white 3' tall. - 'Sensation' Series
Large flowers in shades of pink, red and white. - 'Sonata' Series
Large pink, white, or red flowers. 1-2' tall. - 'Versailles' Series
Cut flower, large blooms in red, white and pink.
- 'Antiquity'
- 'Antiquity', 'Candy Stripe' Mix, 'Chocolate', 'Cosmic' Series, 'Daydream', 'Early Wonder', 'Gazebo' Mix, 'Picotee', 'Psyche Mix', 'Purity', 'Seashells' Mix, 'Sensation' Series, 'Sonata' Series, 'Versailles' Series
- Tags:
- Cultivars / Varieties:
-
- 'Antiquity'
1-2'. flowers early, 2" flowers. - 'Candy Stripe' Mix
White flowers with stripes along the length of the petals - 'Chocolate'
Uncommon variety, chocolate scented, deep maroon flowers - 'Cosmic' Series
1' tall with yellow or orange flowers. - 'Daydream'
Pale pink flowers, darker pink towards the center. - 'Early Wonder'
White or pink flowers. - 'Gazebo' Mix
White, pink and red flowers. 3-4' in height. - 'Picotee'
White flowers with reddish-pink edges, light red lines running the length ft the petals, yellow centers. - 'Psyche Mix'
4-5' tall, lavender-pink or white flowers. - 'Purity'
White flower - 'Seashells' Mix
Trumpet-like flowers, petals rolled into tubes. Red, pink and white 3' tall. - 'Sensation' Series
Large flowers in shades of pink, red and white. - 'Sonata' Series
Large pink, white, or red flowers. 1-2' tall. - 'Versailles' Series
Cut flower, large blooms in red, white and pink.
- 'Antiquity'
- 'Antiquity', 'Candy Stripe' Mix, 'Chocolate', 'Cosmic' Series, 'Daydream', 'Early Wonder', 'Gazebo' Mix, 'Picotee', 'Psyche Mix', 'Purity', 'Seashells' Mix, 'Sensation' Series, 'Sonata' Series, 'Versailles' Series
- Tags:
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Attributes:
- Genus:
- Cosmos
- Species:
- bipinnatus
- Family:
- Asteraceae
- Uses (Ethnobotany):
- Cutting garden
- Life Cycle:
- Annual
- Recommended Propagation Strategy:
- Seed
- Country Or Region Of Origin:
- Mexico and southwest North America
- Wildlife Value:
- Attracts pollinators, birds and butterflies.
- Play Value:
- Attractive Flowers
- Attracts Pollinators
- Colorful
- Easy to Grow
- Dimensions:
- Height: 2 ft. 0 in. - 4 ft. 0 in.
- Width: 2 ft. 0 in. - 3 ft. 0 in.
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Whole Plant Traits:
- Plant Type:
- Annual
- Habit/Form:
- Clumping
- Erect
- Growth Rate:
- Rapid
- Maintenance:
- Low
- Texture:
- Medium
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Cultural Conditions:
- Light:
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- Clay
- Loam (Silt)
- Sand
- Soil pH:
- Alkaline (>8.0)
- Neutral (6.0-8.0)
- Soil Drainage:
- Good Drainage
- Occasionally Dry
- Available Space To Plant:
- 12 inches-3 feet
- NC Region:
- Coastal
- Mountains
- Piedmont
- USDA Plant Hardiness Zone:
- 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b, 11a, 11b
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Flowers:
- Flower Color:
- Gold/Yellow
- Pink
- Purple/Lavender
- White
- Flower Inflorescence:
- Head
- Flower Value To Gardener:
- Good Cut
- Long Bloom Season
- Long-lasting
- Showy
- Flower Bloom Time:
- Fall
- Spring
- Summer
- Flower Shape:
- Saucer
- Tubular
- Flower Petals:
- 7 - 20 petals/rays
- Flower Size:
- 1-3 inches
- Flower Description:
- 2-4-inch saucer-shaped daisy-like blooms are available in a variety of colors and bloom all season.
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Leaves:
- Leaf Color:
- Green
- Leaf Value To Gardener:
- Showy
- Leaf Type:
- Compound (Pinnately , Bipinnately, Palmately)
- Leaf Arrangement:
- Opposite
- Leaf Shape:
- Pinnatisect
- Leaf Margin:
- Entire
- Hairs Present:
- No
- Leaf Length:
- 3-6 inches
- Leaf Width:
- 1-3 inches
- Leaf Description:
- The lacy, thread-like leaves are deeply cut. They have a fine texture.
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Stem:
- Stem Color:
- Green
- Red/Burgundy
- Stem Is Aromatic:
- No
- Stem Surface:
- Smooth (glabrous)
- Stem Description:
- Unbranched along the erect to ascending stem.
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Landscape:
- Landscape Location:
- Coastal
- Container
- Meadow
- Naturalized Area
- Landscape Theme:
- Butterfly Garden
- Children's Garden
- Cottage Garden
- Cutting Garden
- Pollinator Garden
- Design Feature:
- Border
- Foundation Planting
- Mass Planting
- Small groups
- Attracts:
- Bees
- Butterflies
- Pollinators
- Resistance To Challenges:
- Deer
- Drought
- Dry Soil
- Heat
- Poor Soil
