Oklahoma is a state of forests and prairie. The rich variety of soils, topography, and climatic regimes provide habitat for approximately 2,500 species of flowering plants. Also, because of the east-west orientation of the state, plants from the eastern deciduous forest, Great Plains, and Rocky Mountains can
all reside in Oklahoma. A brief description of the five major vegetation regions in the state, eastern forests, cross timbers, tallgrass prairie, mixed grass prairie, and shortgrass prairie, is presented below.
The eastern forests contain the greatest number of plant species in the state. The most common trees are oaks and hickories in the uplands and oaks, elm, ash, and hackberrys in the bottomlands. Common oaks include southern red, white, northern red, and black. Hickories include shagbark, black,
and bitternut. In the Ozarks and Ouachitas, shortleaf pine is a common tree. Shortleaf and loblolly pines are important species in the Oklahoma timber industry. The Ouachita National Forest in LeFlore County presents an excellent opportunity to view eastern Oklahoma wildflowers.
The cross timbers is a mixture of forests, woodlands, and grasslands. The prevalence of post oak and blackjack oak best characterize the region. The vegetation is often dense forest which is difficult to traverse or open parkland which one can move through freely. The cross timbers is a transition from eastern forests to the grasslands of the west. Lake Thunderbird State Park, the Chickasaw National Recreation Area, and Pontotoc Ridge Nature Preserve are but a few places open to the public with excellent examples of cross timbers vegetation.
Oklahoma’s prairies are divided into three major formations, tall, mixed, and shortgrass prairie. Although grass species characterize the prairies, many species in the legume and sunflower family are also abundant. The tallgrass prairie is
the most widely distribute grassland type in the state. Big bluestem, little bluestem, Indian grass and switchgrass are the characteristic species, although they can be found throughout the state. To learn more about the tallgrass and observe the rich array of wildflowers, a visit to the Tallgrass Prairie Preserve in Osage County is in order. The Nature Conservancy, which owns and manages the Preserve, has reintroduced two key players in tallgrass prairie ecology, bison and fire. In their absence, trees and shrubs often become established in the tallgrass.
Mixedgrass prairie can be found in the western tier of counties. Little bluestem, indiangrass, and dropseeds are common grasses. Sideoats grama, which can be found throughout the state, is abundant as well. Other vegetation types in the mixed grass prairie include stabilized sand dunes, sandsage grasslands, shinnery oak, and mesquite grasslands. Much of the mixedgrass prairie has been converted to wheat and cotton cultivation. The Wichita Mountains National Wildlife Refuge is an excellent location to view mixedgrass prairie. Like the Tallgrass Prairie Preserve, the Refuge has a population of bison and maintains a fire regime that aids in maintaining the prairie.
The shortgrass prairie reaches its greatest extent in the Panhandle. Important grasses include blue grama and buffalo grass. Sideoats grama and hairy grama are also common. Much of the shortgrass prairie has been converted to row crop production, but large areas persist as pastures on shallow soil. A good place to view shortgrass prairie vegetation is at Black Mesa State Park. Also at the Park are examples of Rocky Front Range vegetation, where pinyon pine and one-seed juniper are common.
Oklahoma has an interesting variety of state plants. These plants are featured across the bottom map section. From left to right, on either side of the map, the state plants of Oklahoma include Indian blanket (Gaillardia pulchella), Indiangrass (Sorghastrum nutans), Redbud (Cercis canadensis) and Mistletoe (Phoradendron leucarpum). Information about each of these plants follows.
Indian blanket (Gaillardia pulchella) This plant was named the state wildflower in May 1986 due mainly to the efforts of Oklahoma botanist, Dr. Doyle McCoy. It symbolizes Oklahoma’s scenic beauty as well as the state’s Indian heritage. A member of the Sunflower family (Asteraceae), it is typically found in shallow, rocky soil and blooms from May to August.
Indiangrass (Sorghastrum nutans) The state grass of Oklahoma is one of the four dominants grasses of the Tallgrass prairie ecosystem, both here in Oklahoma and across other states. This grass was selected to be the state grass in January 1972. It was selected to represent Oklahoma because it can be found in all 77 counties. Indiangrass can grow to be eight-feet tall during optimal conditions and is an important forage grass for livestock and wildlife.
Redbud (Cercis canadensis) The Redbud tree is a relatively small understory tree that produces flowers on bare branches
in mid to late March. A member of the Bean family (Fabaceae), its small butterfly-like flowers vary in color from light pink to a purplish red. In the wild it is most often found in valleys, ravines or along hillsides. It is also used extensively as an ornamental tree in urban gardens and landscaping throughout much of the United States. The Redbud has been the state tree of Oklahoma since March 1937. In 1939 a law was passed that makes it illegal to harm Redbuds along Oklahoma’s highways.
Mistletoe (Phoradendron leucarpum) The oldest of all Oklahoma symbols, mistletoe has been the floral emblem of Oklahoma since 1893 (14 years before statehood). Mistletoe grows on a variety of trees throughout the state but often prefers elm species. It is particularly bountiful in the southern regions of Oklahoma.
Mistletoe is a hemiparasite, meaning that it is anchored
to a host tree and dependent on it for water. But it is not totally dependent on its host for nutrients as it is capable
of photosynthesis. The dark green, fleshy leaves and white berries are easy to spot in bare trees during the fall and winter months. Mistletoe has many legends and traditions associated with it. Some say that it was picked to be the floral emblem of Oklahoma territory because it was often placed upon the graves of early settlers who died during the winter months when no other green plants were available.