Plant of the Week
Helianthus mollis range map. USDA PLANTS Database.
Ashy sunflower plants. Photo (c) 2011 David D. Taylor.
Close up of the flower head. Photo (c) 2011 David D. Taylor.
Leaves and stem of the ashy sunflower. Photo (c) 2011 David D. Taylor.
Ashy Sunflower (Helianthus mollis Lam.)
By David Taylor
Ashy Sunflower is a member of the Asteraceae, the Sunflower family. In older manuals and guides, this family is called the Compositae because the 'flowers' are a composite of many flowers, often of different types. The many species of plants in this family are grouped based on the arrangement and type of flowers. All members of the family produce one or more heads (capitulum, the term used in technical keys) of flowers. This and other sunflowers have two different types of flowers, ray flowers and disk flowers and in turn, these can have male and female parts, or either one or the other. The ray flowers look like petals, but each is actually an individual flower. The disk flowers are at the center of the head, inside the ring of ray flowers. The disk flowers are usually small. Using a hand lens, one can see the distinct tips of 5 petals in each flower. The disk flowers closest to the ray flowers open first.
This sunflower is 0.5 – 1.0 meters (1.6 - 3.3 feet) tall. The stem is rigid and covered in soft spreading hairs that give it a white to gray cast. Leaves are opposite (rarely alternate near the top), wider at the base than the top, and are 6 - 15 centimeters (2.4 - 6 inches) long by 3-7 centimeters (1.2 to 2.8 inches) wide. They also are covered in dense hairs, resulting in a white to grayish cast. It is from this coloration that the name ashy sunflower is derived. Heads are generally borne individually or in clusters of 2 or 3, and may be found in the axils of leaves from the top to above half way down the plant. Each head generally has 15-30 ray flowers that are 1.5 - 3.5 centimeters (0.6 - 1.4 inches) long, and numerous disk flowers. Both the ray and disk flowers are yellow. The center of the containing the disk flowers is 2-3 centimeters (0.8 - 1.2 inches) wide. The entire head is 3.5 - 6.5 centimeters (1.4 - 2.6 inches) wide.
Ashy sunflower is an open land species, generally on drier, often sandy soils. It is a species of prairies and other grasslands, roadsides, savannas, and woodlands and sometimes old fields. It also occurs in forest openings. It is found from Michigan, Iowa, and Nebraska south to Texas and east to the Atlantic with the exception of Florida, Vermont, and New Hampshire. It is also known from Ontario.
This species flowers in July to September depending on the part of the country in which it is found. It is an excellent prairie garden species and is sold by a number of nurseries. Numerous finches will eat the seeds directly from the heads.
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