Growth Stages of Fox Tail
Foxtails (Setaria spp.) Inhabit disturbed areas such as agricultural land, orchards, roadsides, ditches and gardens; yellow foxtails (Setaria pumila) will even spread to yards. These summer annual grasses are among the most severe of the summer annual weeds due to their abilities to successfully invade — and take over — many types of habitats.
Foxtail seedlings are tough to spot and even harder to identify since the distinctive seed head has not developed yet. They begin parallel to the bottom with their leaves developing in their thick stem. Seedlings can vary in appearance depending on species. The foxtail’s first true leaf reaches nearly 1 inch long and 1/8-inch wide. Once germinated, the plants can reach maturity and develop seed within 40 days.
Many foxtails grow in loosely gathered clumps; a few, however, may erect a single stem. At maturity, foxtails can reach over 4 feet tall. Leaves branch near the base of the plant; mature plants have thick, pointed leaves which spiral slightly. Leaves often have slightly hairy surfaces. Old foxtail plants might cover a large area, especially in disturbed areas where the soil is ideal for their growth.
Mature foxtails possess a distinguishing, fuzzy-looking tree head which changes in colour depending on species. Green foxtail (Setaria viridis), for example, often has green seed heads, but deep, purplish-red isn’t uncommon. This species typically blooms May through November. Yellow foxtail has yellowish seed heads which reach 2 to 5 inches long. Yellow foxtail blooms June through December. Giant foxtail (Setaria faberi) blooms June through November with 3- to 7-inch seed heads. The seed heads often turn tawny or yellowish in fall.
The seeds blow in the wind, latch onto the fur of animals or are otherwise removed from the plant. Seeds can remain dormant for nearly three years. The seeds will germinate almost immediately if the conditions are appropriate — between 68 and 95 degrees F, beginning the life cycle over again for all these species that are competitive. Because of this, foxtails are especially harmful to spring-sown crops.