These classic cottage garden flowers reach full maturity in about two months.
Cosmos can be slower to germinate, but it then blooms quickly and continues to flower through the fall.
Cosmos flowers look a lot like daisies.
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They come in a broad range of colors, with more cultivars developed every year.
The feathery-looking leaves grow opposite on stems and can be deeply lobed, pinnate, or bipinnate.
When established, the plants can handle drought, poor soil conditions, and general neglect.
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This is a truly low-maintenance plant.
Shorter varieties make very colorful, airy edging plants.
Light
For the best flowering, choose a site that getsfull sun.
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They perform best in medium moisture, well-drained soils, but they will perform adequately in dry soils.
Avoid planting in rich soil; it can cause the plants to get too tall and flop over.
Where water is limited, these are the last plants that require irrigation.
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Temperature and Humidity
Hot weather is ideal for cosmos, and they thrive in any humidity level.
Fertilizer
Fertilizing can negatively impact cosmos.
Cosmos can handle poor soil.
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Too much fertilizer can often lead to strong plants with lots of foliage but few blooms.
Unless your plants seem to be struggling, these plants do not need fertilizer.
Types of Cosmos
There are over 25 species of cosmos.
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With golden yellow blooms, it is very drought tolerant and loves hot weather.
The plant grows 2 to 6 feet tall and comes in double and semi-double flowers.
Some of the more recent cultivars tend to be shorter, more orangy, and with smaller flowers.
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Cosmos bipinnatusare colorful daisy-like flowers that come in white, pinks, reds, and oranges.
At 1 to 4 feet in height, they are shorter thanC.
suphureusand are available in several popular hybrid series.
Although they are not quite as heat-tolerant asC.
bipinnatuswill grow well in just about any sunny space.
Chocolate cosmosis a separate species:Cosmos atrosanguineus.The dark red flowers smell like chocolate.
This perennial is hardy toUSDA zone 7, but it is higher maintenance than annual cosmos.
Like dahlias, it grows from tubers.
If you fall behind, shear the plants by about one-third when most flowers have faded.
This kind of pruning produces a second flush of leaves and flowers.
Cosmos can get weedy.
If you leave the plants in place, they may self-seed for the following growing season.
Propagating Cosmos
Cosmos plants readily self-seed.
It’s best to propagate these plants after the threat of frost is gone.
Although sowing seeds is the easiest way to propagate this plant, you could alsopropagate it via stem cutting.
When you take stem trimmings, it stimulates more leaf and flower growth.
Besides seed, stem cutting is the best way to propagate this plant.
Cosmos grows very quickly but can be killed by a late frost, so don’t rush it.
Loosen the soil to a depth of 8 inches.
Plant the seeds and cover them with 1/4 inch of fine soil.
Potting and Repotting Cosmos
When growing cosmos in pots, ensure the container has bottom drainage holes.
Cosmos can’t handle overly wet, soggy soil.
Plan on growing one cosmos plant per gallon of your container.
Also, tall varieties will need staking in containers.
At the very least, plan on using a heavy, 12-inch diameter container.
Overwintering
Cosmos is an annual.
If left outside in frosty temperatures, they will die.
You will need to snip off any blooms as they form.
This plant’s life cycle ends with flowering when it drops its seeds for the next growing season.
What Do Cosmos Flowers Look and Smell Like?
Cosmo flowers have a pleasant, light scent that attracts pollinators like bees and butterflies.
How to Encourage More Blooms
Cosmos plants need full sun to bloom.
Even the hint of shade can restrict flowering.
Also, to encourage more blooms, you’re gonna wanna deadhead the old blooms.
For faster blooms, prune between the main stem and a leaf.
The lower you cut the stem, the longer it takes to grow more flowers.
Common Problems With Cosmos
Cosmos are easy to grow and maintain over the growing season.
This plant will die and should be disposed of.
It creates a powdery white coating on leaves and causes leaves to yellow and fall off.
If your plant has fungus, use a horticultural fungicide according to the package instructions.
Dispose of these plants since there is nothing you’re able to do to help them recover.
Colonial Spanish priests cultivated cosmos in their mission gardens in Mexico.
The seeds will go dormant in the winter and germinate in the spring when temperatures reach 75 degrees Fahrenheit.
Cosmos is an annual that germinates, flowers, and drops seed in preparation for the following growing season.
Cosmos will languish and eventually die after flowering.
C. bipinnatus are bushy plants that grow to an average height of about 1 to 4 feet.
The flowers come in red, pink, and white.
The leaves are spaced apart along the stem and cut into thread-like segments.
The outer rays of the flowers surround the yellow-colored, clustered central disc of florets.
Meanwhile, C. sulphureus can grow to a height of 2 to 6 feet.
The flowers come in shades of orange, yellow, and red.
It has hairy stems, and the daisy-like flowers have yellow rays and discs.
Plant flowers similar to cosmos, but without the aggressive spread, such aszinnias,dahlias, andmarigolds.
Garden Cosmos.Invasive Plant Atlas of the United States.
Cosmos (Cosmos).Connecticut State Agricultural Experiment Station.
Cosmos bipinnatus.Missouri Botanical Garden.
Fusarium Wilts.Royal Horticulture Society.
Diseases of Cosmos.National Gardening Association.
Powdery Mildew.University of California Integrated Pest Management.
Cosmos: Aster Yellows.University of Minnesota Extension.
