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(updated May 10, 2021) 

Perennial Sunflowers

Helianthus spp.

Asteraceae (Aster Family)

▲▼ flowering perennial sunflower (Sawtooh Sunflower)

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

o   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 the more weedy 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.

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