PlantFiles: Klondike Cosmos, Sulphur Cosmos, Orange Cosmos
Cosmos sulphureus

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!

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 neighbors.

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!

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. :-)

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.

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-shade locations fared as well, but produced more greenery than blooms. I can't complain, though... here it is... the day before Halloween, and they're still putting out flowers despite several nights of "wintery" weather.

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.

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.

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.

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!

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

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.

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.

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.