(Helianthus spp.)
A common site in fallow fields and reclaimed cow pastures members of the Helianthus genus, sunflowers, are hard to miss. With specimens standing upwards of 10 ft tall and bristling with brightly arranged yellow flowers they are quite conspicuous upon the landscape. Along with their penchant for being noticed this group of species has great use as a wildlife and agricultural resource.
The two most common species that are commercially available for establishment and subsequently the most widely distributed in Texas are, annual sunflower (Helianthus annuus) and maximilian sunflower (Helianthus maximiliani).
Annual Sunflower (Helianthus annuus)
Native annual sunflower can be distinguished from other sunflower species by it’s large leaves which are usually 2-7 inches wide, triangular-ovate to ovate-lanceolate in shape, plant height from 1-12 feet, with wide spreading hairs along the peduncle (stem supporting the flower head), and it’s annual life cycle. Most other sunflower species are perennial plants living and growing for multiple years. The flowers of the plant have a 1-5 inch flower head and have 20-25 one to two inch long bright yellow rays that surround the central brownish disk flowers that produce seed. Multiple seed heads are common from the branching stems. Seeds produced are generally no larger than ¼” in length, gray to brown in coloration, with stripes or spots, wedge shaped and there are about 350,000 seeds per pound.
This plant is not favored white-tailed deer forage, but its leaves, shoots, and flower heads will be utilized, especially when the leaves and shoots are young and tender. Flower heads are generally consumed once mature with seeds. Annual sunflower is generally not susceptible to disease and pest infestations. It will support large numbers of diverse insect species without damage for turkey, quail, and songbird consumption. This coupled with large amounts of seed production favored by quail, doves, and many other songbirds such as wintering sparrows, blackbirds, meadowlarks, titmice, and chickadees make this plant an excellent choice for wildlife plantings.
Maximilian Sunflower (Helianthus maximiliani)
Maximilian sunflower is a native, upright perennial sunflower named for German botanist Prince Maximilian von Wied-Neuwied, it’s “discoverer”. This species can grow from 0.5 - 9 feet in height. It’s leaves are alternate in arrangement and, often sickle shaped while up to 12” long and 2” in width. The flowers are raised on stalks from the main stem and are from 2-3.5 inches across with 20-40 yellow ray florets surrounding numerous brown disk flowers in the center. The flowers are often densely clustered on the upper portion of the stem and produce seeds ¼” in length starting in late July through about mid-October.
Since Maximilian sunflower is a perennial plant in can spread via seeds or rhizomes which means over time it can form dense colonies. This species is also highly preferred forage for both livestock and white-tailed deer. It is therefore necessary to implement a rotational grazing scheme or defer grazing during the plants early spring growth if seed production is desirable. Native stands of Maximilian sunflower are often indicative of good range conditions and grazing management. This species will often disappear under continuous grazing pressure from livestock or in the presence of high density deer populations. Deer utilization of these plants decreases as the plant matures and becomes more lignified (woody). Just as with annual sunflower this plant supports insect life that can serve as a food resource for many game and non-game birds, and provides seeds which are beneficial for turkey, quail, dove, and resident/migratory songbirds.
Overall Use and Establishment:
As anyone who has dove hunted in a sun flower field can attest; sunflower fields can serve as important feeding sites for resident and migratory mourning doves. Mowing/shredding strips through these fields can assist in recovery of game, providing bare ground for feeding, and allowing seed to shatter from mature plants. Shredded strips should be generally twice as wide as unmowed strips to aid in recovery of game. Deferring fall plowing until after October is also beneficial for doves to allow for maximum uptake of sunflower seeds available.
Leaving standing stems of dead sunflowers over winter can provide additional screening and roosting cover for wintering birds using the fields. These dead stems provide protection from aerial predators, and insulation against the cooler temperatures that occur during the winter months. These standing stems can also assist in the forming of vegetative colonies of Maximilian sunflower if the roots are left undisturbed from year to year.
Planting Sunflowers:
Annual sunflower- prefers full sun, is tolerant of most soil types, and is adapted to droughty conditions. Seeds can stay dormant in the soil seed bank for years waiting for soil disturbance, moisture, or other factors to trigger their growth. Planting can be established readily with a prepared seed bed and a planting rate of 3-5 lbs/acre for a pure stand or 0.5-1 lb if part of a range mix planted at a depth of no greater than 1” with ¼” to ½” being optimal. Seed can be broadcast or drilled depending on equipment available with plantings needing to be established November- January to allow cool soil temperatures to break seed dormancy. Annual sunflower can only be established by seeds so after establishment; periodic breaking of the soil through shallow disking in October-November may be necessary to maintain stands naturally.
Maximilian sunflower- prefers full sun, is tolerant of most soil types, and is adapted to droughty conditions, but needs at least 18 inches of rainfall. Seeds can be established on a well prepared seed bed and broadcast or drilled using 3 lbs seed/acre for pure stands or 0.5-1 lb if part of a range mix. Seeds should be planted ¼”- ½ “ in depth and from November- February to break seed dormancy and for optimal establishment of stands. Excessive grazing by livestock or deer can prevent establishment and late season mowing may help the following year’s vegetative growth. Utilizing rotational grazing can assist in the long term survival of Maximilian sunflower stands.
So, whether utilizing these plants for landscaping, wildlife viewing, or wildlife harvesting you can’t go wrong. As the summer and fall months continue look around the countryside and enjoy the brilliance of these plants both visually and biologically.
