Restoring the Tallgrass Prairie: An Illustrated Manual for Iowa and the Upper Midwest

9. Grasses

Grasses Name and classification: All are native grasses of the Poaceae (Gramineae ) family and are monocotyledons. This important grass family has about 525 genera and 5,000 species, providing food for both humans and animals. L.]. Eilers lists 151 native species in Iowa. The most prominent are big bluestem, little bluestem, Indian grass, switchgrass, and prairie dropseed. They are listed in alphabetical order by genus and species, with common names also given. Location: Native grasses are mostly common to frequent throughout Iowa and the tallgrass prairie as listed with each species. As much as 60 to 90 percent of the vegetation was grass before the prairie was broken. Grasses are the framework of the prairie. Their roots, present for thousands of years, gave the high organic content and black color to the prairie soil. Soil, moisture, and sun requirements are given for each species. The pH range is broad for all the species in this study. Native grass adapts to the variety of soil and hot-dry summers on the prairie. Plant description: Understanding the characteristics of prairie grass will help you in your prairie seed selection and management. They have several built-in features to ensure their existence. The roots grow very long, spread densely, or do both. Big bluestem roots have been known to be 12 feet long. Leaves will curl in dry, windy weather so that less area is exposed, conserving the moisture in the leaf. Roots store starch as food for the plant. When 255 there has been a dry season, the plant will take time to renourish itself and the roots before it is able to use the energy for making flowers, fruit, and seeds. They withstand drought as well as fires and moderate grazing. This is not only due to the root structure but also because the aboveground growth tissue of grass is located toward the base of the leaf or the shoot, rather than at the tip. Yes, grasses do bloom, but the bloom is small because it is windpollinated and not dependent on insects for pollination. Stems are mainly hollow except at the node, where the leaf attaches. They are also round in comparison to the sedges, which have a triangular stem. Without a showy flower, grass identification becomes more difficult. A useful gUide is Grasses by Lauren Brown. Roots are listed as sod-forming or bunch-forming. Sod-forming grasses spread by rhizomes or stolons, growing horizontally to form a dense mat or sod. Once a dense sod is formed, it is hard for other species to penetrate it. Bunch-forming grasses grow vertically in clumps and tend not to crowd out the forbs that are established. Some bunch-forming grasses, as listed, also spread by rhizomes to become sod-forming. Germination: Special treatments are listed to break dormancy with each species. Dry stratification is sufficient for most prairie grasses. Dry stratification requires the seeds to be exposed to cold, dry conditions for 30 days. Propagation: Grasses are classified as cool-season and warm-season. Cool-season grasses grow in the cool weather of the spring and fall. They emerge in the spring before the warm-season plants. Cool-season grasses, legumes, and weeds include many aliens that germinate four to six weeks before warm-season prairie grasses. Their competition is a factor that needs to be taken into consideration. They include bluegrass, fescue, bromegrass, timothy, red top, alfalfa, clover, and various trefoils. Cool-season grasses are often sod-forming, but the cool-season native species in this study are all bunch-forming. These include Canada wild rye, June grass, and porcupine grass and have a usefulness in the prairie. Bunch-forming grasses allow forbs room to establish if they mature before the grass roots become dense, and they crowd out weeds. The amount of grass should be kept from 25 to 50 percent of the mix with forbs. Little bluestem and side-oats grama are short enough to emphaSize the wildflowers. Big bluestem and Indian grass give more competition. Dropseed is ornamental in small amounts. Switchgrass can become aggressive and should be planted sparingly. June grass is a nice addition for dry soils. Prairie grasses grow down, not up. The root system establishes itself first, 256 Grasses before the grass appears, and continues to be the major part of the plant. The first year the top growth normally amounts to a narrow, straight leaf until late in the...