Sawtooth Sunflower
Sawtooth Sunflower
Helianthus grosseratus Marlens
Asteraceae (Sunflower Family)
▲ ▼ mature flowering plants
▲ leaves showing "sawtooth" leaf margins
▲ ▼ inflorescences
▲ inflorescence "bud" and leaves
Helianthus grosserratus Marlens, Sawtooth Sunflower: (Bayer Code: HELGR; US Code HEGR4)
- U.S. native creeping perennial, rhizome-producing wildflower that grows 3-12 feet tall or more, usually with unbranched, red-green to purplish ridged stems; stems hairless, often have a thin, white, waxy coating
- Leaves are opposite (sometimes alternate), lanceolate usually with toothed margins (like a saw-blade) and a pointed tip, although sometimes leaves have smooth or nearly smooth margins; leaves have short petioles; upper leaf surface is rough-textured and hairy; lower surface is soft hairy
- Head inflorescences are 2.5-4 inches in diameter, produced at stem tips, with 14-20 yellow ray florets (“petals") that are puckered where they join the head, and 100 or more yellow disk florets
- Bracts below the head are in overlapping rows, lanceolate, 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, reduced tillage fields; can tolerate some disturbance
- The red-green to purplish stems with waxy bloom are characteristic for this species of perennial sunflower; similar Maximilian Sunflower (Helianthus maximiliani) has green, hairy stems
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
- Click on links of above individual plant names to see more information on each one
- 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)