Klondike Cosmos, Sulphur Cosmos, Orange Cosmos
Cosmos sulphureus

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Cosmos (KOS-mus) (Info)
Species: sulphureus (sul-FER-ee-us) (Info)
Synonym:Bidens sulphurea
View this plant in a garden

Category:

Annuals

Height:

24-36 in. (60-90 cm)

Spacing:

9-12 in. (22-30 cm)

Hardiness:

Not Applicable

Sun Exposure:

Full Sun

Danger:

Parts of plant are poisonous if ingested

Bloom Color:

Red

Orange

Bright Yellow

Bloom Time:

Mid Summer

Late Summer/Early Fall

Foliage:

Smooth-Textured

Other details:

May be a noxious weed or invasive

This plant is attractive to bees, butterflies and/or birds

Drought-tolerant; suitable for xeriscaping

Self-sows freely; deadhead if you do not want volunteer seedlings next season

Soil pH requirements:

7.9 to 8.5 (alkaline)

Patent Information:

Non-patented

Propagation Methods:

From seed; direct sow outdoors in fall

From seed; direct sow after last frost

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds

Properly cleaned, seed can be successfully stored

Regional

This plant has been said to grow in the following regions:

, (3 reports)

Holly Pond, Alabama

Northport, Alabama

Calistoga, California

Citrus Heights, California

Long Beach, California

Sacramento, California

San Diego, California

San Francisco, California

Stockton, California

Delray Beach, Florida

Hollywood, Florida (2 reports)

Old Town, Florida

Pinellas Park, Florida

Port Orange, Florida

Saint Petersburg, Florida

Sarasota, Florida

Winter Springs, Florida

Cordele, Georgia

Villa Rica, Georgia

Kailua, Hawaii

Anna, Illinois

Itasca, Illinois

Washington, Illinois

Iowa City, Iowa

Lansing, Kansas

Barbourville, Kentucky

Zachary, Louisiana

Upper Marlboro, Maryland

Saint Cloud, Minnesota

Florence, Mississippi

Madison, Mississippi

Mathiston, Mississippi

Kansas City, Missouri

Roswell, New Mexico

Chapel Hill, North Carolina

Fuquay Varina, North Carolina

Rowland, North Carolina

Massillon, Ohio

North Ridgeville, Ohio

Portland, Oregon

Malvern, Pennsylvania

Tobyhanna, Pennsylvania

Darlington, South Carolina

North Augusta, South Carolina

North Charleston, South Carolina

Simpsonville, South Carolina

Knoxville, Tennessee

Lenoir City, Tennessee

Arlington, Texas

Austin, Texas

Blanco, Texas

Bulverde, Texas

Canyon Lake, Texas

Fort Worth, Texas

Houston, Texas

Plano, Texas

Princeton, Texas

Prosper, Texas

Round Rock, Texas

San Angelo, Texas

San Antonio, Texas

Ogden, Utah

Cascade, Virginia

Chesapeake, Virginia

Palmyra, Virginia

Kalama, Washington

Lakewood, Washington

Spokane, Washington

show all

Gardeners' Notes:

16
positives
2
neutrals
0
negatives
RatingContent
Positive

On Jan 4, 2015, iowhen from Iowa City, IA (Zone 5a) wrote:

Absolutely gorgeous blooms, non-stop from summer through fall. Mine were over five feet tall.

Positive

On May 26, 2013, PAgirl60 from Tobyhanna, PA (Zone 5a) wrote:

I grew "Bright Lights" cosmos and was very pleased. I grew it in pots and the flowers bloomed all summer right into fall. It grew no taller than about 24 inches which was perfect for large pots. This year I am trying it directly in a flower bed. I think it will look great as a border. Even though the mix was supposed to include yellow and red flowers, I only got orange. I still loved them anyway!

Neutral

On Jul 8, 2012, Thebotanyboss from Johnson City, TN wrote:

Very decorative plant. The bright orange really added some color to the garden. Didn't seem to attract as many insects as other plants.Grows well outdoors in spring but it looks like it would grow well inside too. Eyecatching color.

Positive

On Apr 14, 2011, Betsy2 from Darlington, SC wrote:

This flower is brilliant in color. Definitely an attraction for butterflies and bees. It grows every year in my yard because I let it reseed itself. I will say this, it can be invasive. I don't mind because I have it planted where it has plenty of room to grow. Flower stalks can grow to five feet but usually around 3-4 feet.

Positive

On Aug 6, 2008, Seandor from Springfield, MA (Zone 6a) wrote:

Received seeds in trade - plants are fabulous - but they certainly grew VERY tall - almost 5 feet - maybe it's all the rain we received this summer . . . get this plant - neighbours will be soooo impressed!

Positive

On Oct 29, 2006, Cordeledawg from Cordele, GA (Zone 8a) wrote:

This particular species, sulphureus, imo is a far superior garden specimen than any other cosmos I have grown. In fact, until I discovered this one, I was swearing off cosmos all together. I planted it thinking I had planted either mexican sunflower or a species of coreopsis only to discover it's true identity when I began trying to ID it's seeds. To collect the seeds, by the way, take the spent bloom early, before it dries out. Place the spent bloom in a dry open bag inside your house. It will dry out and explode like a starburst. The seeds are long and somewhat arching. This plant is best planted next to a fence to allow the airy branches to grow through the fence for support. This plant is a magnet for butterflies and hummers, not to mention the ooohs and yaaahs from your neighb... read more

Positive

On Sep 12, 2006, Krispi from Canyon Lake, TX (Zone 9b) wrote:

I love this plant, everywhere I throw these seeds, they come up. We have a lot of caliechi, and this plant will come up through it, and it is like concrete. The deer don't like it! I have had a blast trying to see where it won't come up, so far havn't found any place like that!

Positive

On May 2, 2006, Suze_ from (Zone 7b) wrote:

I rarely fuss with annuals (I'm more of a perennial person), but I do enjoy having various varieties of cosmos dependably reseed and provide additional depth and 'filler' in my garden.

And the good old yellow/orange tall cosmos is the first one I started out with. :-)

Positive

On Mar 12, 2006, SW_gardener from (Zone 6a) wrote:

I planted some of these last summer and one of them appears to have over wintered!!! The part of the plant that was mulched under leaves is the part that survived. These arn't even listed as being perennial in warmer climates and it somehow lived! We had a mild winter this year, we still got snow though. I'm zone 6.

Positive

On Oct 30, 2005, phrostyphish from Tuscaloosa, AL wrote:

If you have a corner of your yard that's barren and receives at least half a day of sunshine... if you need a background for a landscape design... if you have a field full of weeds that needs some decorating...

This plant virtually thrives on neglect - at least, in my yard it does.
My soil is composed of a LOT of red clay, and our summers can be nearly tropical some years. In 2003 and 2004, it seemed we didn't get much rain at all. Without any help from me in the form of supplemental watering, they produced an abundance of flowers. This year, we got our fair share of summer showers... and I did notice an increase in their production. The plants growing in full sun reached a height of about six feet before bowing down to the ground under their own weight. Those in part... read more

Positive

On Jun 15, 2005, htop from San Antonio, TX (Zone 8b) wrote:

I had bought 4 large containers of these plants while they were in full bloom in the middle of March. They did not live long. I think perhaps it was because we had a very cool and wet spring. Now that the daytime temperatures have warmed up, I have been pleasantly surprised with lots of seedlings where the containers had been sitting and in the containers the original plants had been in before I discarded them after they died. I have been sharing them with my neighbors. I will see how the new plants do and report back.

Update 10/23/05: I ahve changed my rating to "Positive". The plants have performed very well all summer and into October. So, the original problem was that I bought and planted them when it was too cool for them.

Positive

On Aug 30, 2004, jnn from Chapel Hill, NC (Zone 7b) wrote:

We grew these in our old garden in Cary, NC and they were maintenance-free, self seeded like crazy and very pretty. They did attract both butterflies and bees quite a bit. They seem to like a bright sunny spot. We tried to grow in a more shaded area at our new house, but they didn't do as well. We'll plant some again next spring in a more sunny spot.

Positive

On Jul 2, 2004, punaheledp from Kailua, HI (Zone 11) wrote:

last year I got a packet of "Bright Lights". Like very much. While the life cycle is only a few mos. for mine (I pull when they start to get scraggly), they sprout quickly, flower quickly and seed easily. Before one generation is gone the next is set to bloom. Mine range in size from 10"-18" (I don't fuss for more) though packet said 3'-4'. I toss seeds where ever there's a bare spot (I just scatter without covering) and they fill it quickly with a bright splash of color. have also used them to fill a bed while slower growers are getting started. The orange in the pack are much more prolific than yellow, perhaps hardier? or maybe more in original mother seeds... Zone 11.

Positive

On Oct 9, 2003, suncatcheracres from Old Town, FL wrote:

I live near Cross City, Florida, where the old railroad track has been turned into the Nature Coast Bike Trail, which runs for over thirty miles to several other cities, and crosses the nearby Suwannee River over the old railway trestle. Cross City plants this cosmos for several blocks along this very sunny bike path right through its downtown in mid-summer, and by September it looks as if "a river of orange" is running through the town. This plant is really spectacular in mass!

Positive

On Aug 20, 2003, Monocromatico from Rio de Janeiro
Brazil (Zone 11) wrote:

This is a tropical herb, one of the most ornamental of the genus Bidens. It has bright orange flowers with broad peripheral flowers ("petals"). The seed pods have characteristic "teeth" that ataches to everything (animal fur, pants, shoes...), and that's the way it propagates itself. Accidentally you can carry its seeds somewhere else, so clean your clothes after manipulating this plant (that's why I classified it as "invasive" above).

It grows spontaneously on abandoned areas with poor soil, also on sandy ones. On gardens, it's usualy planted on organic soils, so I guess it's tolerant to may kinds of soil, as long as it's well drained. Needs full sun, heat, and average watering

Positive

On Feb 1, 2003, asturnut from Anchorage, AK (Zone 4b) wrote:

This comsos has a very different appearance than many of the other common varieties. The foliage is much airy-er. It reseeds like mad and can be a bit of a nuicence if you don't keep it in check. Butterflies and drawn to it in droves. It's a wonderful carefree plant to grow. This is a good one for kids to try out.

Positive

On Jul 5, 2002, JoanneAW wrote:

Will even grow in 100+ degree summer weather. This is a semi-dwarf cosmos of about 2' in the southwest, and will grow in containers. Neglect is the best kind of care for cosmos. Go light on fertilizing or don't fertilize at all.

Butterflies seems to love the yellow flowered cosmos. "Bright Lights" is a favorite.

Will self seed.

Neutral

On Jun 17, 2001, Terry from Murfreesboro, TN (Zone 7a) wrote:

Cosmos sulphureus is smaller-flowered and shorter than the familiar pink and white C. bipinnatus.

A desert species that is very drought tolerant, Sulphur Cosmos blooms from mid-summer through frost and is very adaptable. Useful in dry, open areas where other flowers fail. In freeze areas, must be planted in spring.