Willowleaf Sunflower
Willowleaf Sunflower
Helianthus salicifolius A. Dietr.
Asteraceae (Sunflower Family)
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Helianthus salicifolius A. Dietr., Willowleaf Sunflower: (Bayer Code: not known; US Code: not known)
- U.S. native creeping perennial, rhizome-producing wildflower that grows 4-9 feet tall or more, usually with unbranched (except in upper portions during flowering), green hairless stems that often have a thin, white, waxy coating
- Leaves are very thin (linear), long (up to 8 inches) and usually numerous along the stem, with fewer toward upper stem than midstem; leaves are alternate (although spacing can be close and almost whorl-like at times), usually with smooth margins (sometimes with small teeth on margins) and a pointed tip; leaves lack petioles; leaves lack hairs and often curve downward from stem to tip of leaf
- Head inflorescences are 2-3 inches in diameter, with 10-20 yellow ray florets (“petals") that are puckered where they join the head, and 50 or more yellow disk florets
- Bracts below the head are in overlapping rows, linear, with tapering, pointed tips; bract tips stand out from base of head
- Flowering from late summer through autumn
- Prefers full-sun, pastures, prairies, rangeland, glades, right-of-ways; prefers higher pH (limestone-based) soils
- The numerous, very thin, downward curving leaves and green stems with a waxy bloom are characteristic for this species
Perennial sunflowers:
- Include Ashy Sunflower, Texas Blueweed, Maximilian Sunflower, Sawtooth Sunflower, Western Sunflower, Willowleaf Sunflower, Jerusalem Artichoke, and other species
- All are creeping perennial weeds that form rhizomes and/or creeping roots that allow them to spread to form colonies with maturity
- Most are palatable to livestock, except in fertile soils, where high nitrate accumulation may cause poisoning, but may be seen as weedy in reduced tillage crops
- Once established, these species can be hard to control, but most (not all) are not considered to be weedy
- Most produce relatively tall (4-8 feet tall or more), unbranched, leafy stems with linear, lanceolate to ovate/triangular, rough-textured leaves; upper stem portions are usually branched with the onset of flowering, so that each branch stem tip has a flower head
- Flowers for most perennial sunflowers quite similar (with some exceptions); they are
in terminal clusters, flowering usually sometime from
mid-summer to late autumn, with yellow ray flowers and yellow to brown disk flowers;
total flower diameter is usually 2-4 inches
- Perennial sunflower “flowers" are usually smaller than annual sunflower “flowers," such as with Annual Sunflower (Helianthus annuus) or Prairie Sunflower (Helianthus petiolaris)
- Usually, it is more of the stem and leaf characteristics that are used to identify the different perennial sunflower species
Most perennial sunflowers are native plants that usually do not cause harm in grazing or haying situations (maybe with the exception of Texas blueweed).
Perennial sunflowers provide food and nectar for native insects (including bees and butterflies), birds and other animals, and generally should not be killed indiscriminately.
Maintaining proper grazing levels can often reduce their unwanted increase in pastures and rangeland.
(Updated May 17, 2021)