Hardiness: USDA Zone 4a: to -34.4 °C (-30 °F) USDA Zone 4b: to -31.6 °C (-25 °F) USDA Zone 5a: to -28.8 °C (-20 °F) USDA Zone 5b: to -26.1 °C (-15 °F) USDA Zone 6a: to -23.3 °C (-10 °F) USDA Zone 6b: to -20.5 °C (-5 °F) USDA Zone 7a: to -17.7 °C (0 °F) USDA Zone 7b: to -14.9 °C (5 °F) USDA Zone 8a: to -12.2 °C (10 °F) USDA Zone 8b: to -9.4 °C (15 °F) USDA Zone 9a: to -6.6 °C (20 °F) USDA Zone 9b: to -3.8 °C (25 °F)
Other details: Average Water Needs; Water regularly; do not overwater
Soil pH requirements: 6.1 to 6.5 (mildly acidic) 6.6 to 7.5 (neutral) 7.6 to 7.8 (mildly alkaline)
Patent Information: Non-patented
Propagation Methods: By dividing the rootball By dividing rhizomes, tubers, corms or bulbs (including offsets) From seed; direct sow outdoors in fall From seed; winter sow in vented containers, coldframe or unheated greenhouse From seed; sow indoors before last frost From seed; direct sow after last frost
On Sep 18, 2007, BlackDogKurt from Seymour, CT wrote:
This was one of the longest blooming perennials in my garden this year. The individual flowers last an extremely long time, so much so that I never even had to deadhead mine. The only problem that I had was that I did not realize how large this plant would get when I first lanted it, so much so that it crowded out some nearby plants in the second year. It is not invasive, but give it plenty of space -- it will need it. But the blooms are stunning and plentiful -- a sea of yellow all summer long!
On Aug 7, 2006, MichelleVQuinn from Grand Rapids, MI (Zone 5b) wrote:
Can't say that I've had much luck with my 2 helios. They are on the south side of my house and don't get a ton of sun...perhaps a change of location would help. They also don't get a ton of water as the UG sprinklers need to be repaired on this side of the house, so I hand/hose water. I've deadheaded them and they actually got worse...look dry brown and lean over (contrary to the 'no-staking necessary' comments.)
On Aug 8, 2003, DeeGoods from Saint Clair Shores, MI wrote:
Nice flower requires little maintenance. We need to put a cage around it for support. The birds love the seeds. The seeds reseed themselves to the point of being evasive, but can be controlled by deadheading – but then the birdies miss out. We always have tons of seedlings to give away. I am in Michigan zone 5.
This plant is very hardy. It requires no staking and blooms continually throughout the summer into early fall. If you don't want small clumps of these plants throughout your garden you must either cut the flowers (they make long lasting cut arrangements) or dead head. I had about 20 volunteer plants in my garden this spring from the initial three plants I started with.
This plant has been said to grow in the following regions:
, Heber Springs, Arkansas Menifee, California Seymour, Connecticut Cordele, Georgia Lula, Georgia Cottage Hills, Illinois St Charles, Illinois Galena, Indiana Warren Park, Indiana Ewing, Kentucky Hebron, Kentucky Kemp Mill, Maryland Dracut, Massachusetts Bloomfield Township, Michigan Dearborn Heights, Michigan Cleveland, Mississippi Walnut Grove, Missouri Lincoln, Nebraska Chester, New York Edgeley, North Dakota Saint Martin, Ohio East Norriton, Pennsylvania Kalama, Washington Walnut Grove, Washington Buckhannon, West Virginia Fond Du Lac, Wisconsin Iola, Wisconsin