By Eric Grahmann
Annual sunflower (Helianthus annuus; or common sunflower) is a common forb (weed) found in a variety of habitats across Texas. A native species, not to confused with the numerous cultivars that have been developed from this wild type (e.g., black oil sunflower), it is an easy plant to manage as it can return year after year without reseeding on the same plot with the simple addition of soil disturbance. However, the tricky part about getting this valuable plant to provide food for dove is in its establishment in areas where its seeds are not yet pervasive in the soil.
Dove hunters are well aware that this species is a choice food plant for mourning dove, as a healthy stand can produce fabulous wing shooting and nearly comical concentrations of birds. This is because annual sunflower ranks among one of the most popular and fed upon seeds across the mourning doves’ geographic range. In Texas, up to 60% of crop contents by weight on average can be comprised of annual sunflower where the plants are found (Fig 1). White-winged and white-tipped dove also make use of annual sunflower when it grows in proximity to their preferred habitats. Crude protein and carbohydrates average 15.2% and 17.4% respectively, and fat content ranges from 15-20%; thus, this seed alone meets the basic nutritional needs of dove. One additional virtue about annual sunflower is that seed production is prolonged as all plants and flowers do not mature at exactly the same time (like sesame tends to do, Fig 2) and “seed rain” onto the soil surface can extend for as long as stalks are standing. Healthy stands of annual sunflower can produce more than 3,000,000 seeds per acre before conditions become too dry or temperature becomes unfavorable for plant growth.
When considering a plant as common as annual sunflower, it’s amazing that a stand can be so challenging to establish. There are 3 primary reasons that plantings of annual sunflower are unsuccessful. These include 1) seed is sown into soil or sites that are unfavorable, 2) seed is planted too deep, and 3) the manager is too impatient to see the project to fruition because of the phenology of this plants seeds (this last one is a biggie and leads to most failed projects).
First, if annual sunflower is to be sown with the intention that it will provide significant food for dove, it must be done so on sites where it can succeed. Although annual sunflower can grow on soils ranging from sand to clay (even slightly saline sites) with variable fertility, this plant does best on clays and loams with high fertility. Assess your soil by first sending a soil sample off for analysis. Some labs also make custom fertilization recommendations based on the soil analysis results. Sites to be planted must also be in full sun.
Native annual sunflower can be sown at a rate of 2-4 lbs. of seed/acre over a well-prepared seedbed. The area where annual sunflowers are to be cultivated should be disked as deep as possible. Merely scratching the soil surface with a farm implement is enough to stimulate germination of sunflower seeds; however, deep cultivation (>6 inches) is important in helping the plants to grow tall and robust as their roots are allowed pathways through the soil via less compaction towards deeper moisture. Deep disking is fine for stimulating sunflower seed germination over a well-established seed bank, but it should not be done over seeds sown for the first time. Seeds should only be sown over a deep disked area and then passed over with a light drag (just so birds and insects cannot find the seeds on the soil surface). Annual sunflower germination is greatest from the soil surface to 1/8 of an inch. Seeds should not be covered with more than ¼ inch of soil.
Sunflowers are an easy plant to manage as it can return year after year without reseeding on the same plot with the simple addition of soil disturbance.
Finally, the reason most annual sunflower stands fail is because of the finicky plants’ seed phenology and the dove manager’s lack of patience. Annual sunflower has a strong chemical dormancy that is broken only by the combination of soil moisture and cold weather. And thus, most initial plantings sown during spring miss out on this cold-wet widow. Generally, native annual sunflower should be sown during the fall or winter to take advantage of this stratification period. Because annual sunflower seed has a strong dormancy, it takes up to 3 years cultivating the same plot before stands become dense and productive from a dove foraging standpoint (unless you got lucky!).
Once stands become established; however, they are incredibly productive in providing high-quality food for dove and sites for recreational gunning. For an additional management activity, consider mowing dry stalks beginning 1 month before dove season begins (Fig. 3). Strips mowed every other week throughout the 1st and 2nd splits of dove season, keep birds in the area. Just be sure to mow conservatively based on the size of the plot so the longevity of the plot can extend through the season.
As a recap, here are some tips for a healthy stand of annual sunflower if you are seeding from scratch:
1) Focus efforts to cultivate sunflower in clay or loam soils in full sun.
2) Conduct a soil test and amend the soil based on recommendations tailored specifically towards producing sunflower.
3) For rejuvenation of established sunflower patches and before the initial planting, deep disking is best. Disk the same plot each year from early December (Rio Grande Valley) to early March (Panhandle) to stimulate germination.
4) Seeding can take place any time of the year, but be aware that most seed of this species requires a cold-wet stratification period for optimal germination.
5) As always, diverse native plant communities should never be cultivated in lieu of a food plot, and cultivation should only take place in settings that are not prone to soil erosion (e.g., steep slopes or along with riparian areas).
If planted and managed properly, this excellent natural plant can produce large amounts of high-quality dove forage over extended periods. Happy hunting!