The signs of the approaching autumn are cropping up everywhere. The yellows and purples of fall flowers are appearing, the tree leaves are taking on a slight bronze cast, the angle of sunlight is shifting and the hummingbirds are buzzing and dive-bombing anything within reach of their nectar flowers and the sugar feeders.

The signs of the approaching autumn are cropping up everywhere. The yellows and purples of fall flowers are appearing, the tree leaves are taking on a slight bronze cast, the angle of sunlight is shifting and the hummingbirds are buzzing and dive-bombing anything within reach of their nectar flowers and the sugar feeders. They sense the light levels changing and increase their weight up to 40% more before migrating. The male ruby-throats will leave before the females. The northern guys have already started their migration south. In our area, the hummers begin packing up and leaving from mid-August through September. The last of the stragglers come through early October. They are heading to southern Mexico and northern Panama.

Brightly colored tube flowers are irresistible to hummingbirds, but this time of year the native Trumpet Vines, Beebalm, Blazing Star (Liatris) and sunflowers are now in demand. Other plants include Russian Sage, Zinnias, Salvias, Cannas, Geraniums and Lantanas. Keep your flowers watered if nature doesn’t. This assures good food sources for the tiny birds. If feeders are your thing, pay particular attention to the nectar now. The hummers are tanking up more frequently and the nectar levels are now dropping much faster. Clean and refill often to make sure your birds have good reserves before they leave. Their trip is long, the Gulf of Mexico is too warm (currently about 85 degrees F) and more hurricanes loom on the horizon.

Autumn is my favorite time of year. The native prairie grasses are coming into season, and it has taken months for many to attain their true heights and fullness. Oklahoma has three types of prairies: short grass, mixed grass and tall grass. Appreciate these grasslands since less than 10% of the original prairies from even 500 years ago remain because of agriculture, restructure and development. The tall grass prairies used to cover much of central North America. Four distinct tall grasses, all fondly known as the “Big Four”, are recognized in Oklahoma. They are members of our extensive native grass population.

The young bluish colored shoots of Big Bluestem (Andropogon gerardii) are loved by bison and cattle. The warm season grass blooms in August with flower heads that resemble turkey feet. It often reaches over 8 feet in height with dense roots that can penetrate the soil 10 feet down. So thick are these anchors that they were used to make the bricks in sod houses. Only one sod house built by settlers in Oklahoma survives and is located near Cleo Springs in Alfalfa County. Marshal McCully participated in the Cherokee Run in 1893, staked his claim and built his soddy a year later.

Little Bluestem (Schizachyrium scoparium) forms thick clusters with roots that range from 5 to 8 feet long. The flowers are feathery along the stems and turn a reddish color as the seeds mature. Another warm season grass, Little blue provides cover and food for wildlife and is nearly cosmopolitan. It can be found in all but four states.

Switchgrass (Panicum virgatum) can definitely reach 6 feet in height and forms colonies through underground stems called rhizomes. The leaves of this warm season grass may be over a half of inch in width and small flowers form at the ends of thin stems that are grouped together. Switchgrass is a nutritious forage crop, excellent for cattle but horses avoid it. This grass produces good hay if cut before mature. In winter the deer will dig and eat the rhizomes.

Indiangrass (Sorghastrum nutans) is the state grass of Oklahoma. This warm season tall grass grows in clumps or as individuals of blue-green leaves. The stunning floral heads are seen from September until late October. One can easily spot the golden arrows waving in the breeze. Indiangrass is found in every county of Oklahoma. It not only makes good hay, but cover for small mammals.

If you are wondering why the Big Four grasses have warm season in common, realize they grow best in warm soil and high temperatures: spring, summer and fall in Oklahoma. As a side note, Bermuda is a warm season grass (that should be banned in my opinion.) In Bermuda it is called crab grass. This grass spreads through rhizomes and sends roots down 2 to 6 feet. This is great if it were living where it is supposed to be: Western Asia and Egypt. Bermuda is aggressive and can disrupt fledgling native plants trying to become established.

I suppose one could consider Bermuda a short (disgusting) grass, but the true native short grasses found in prairies belong to Blue grama (Bouteloua gracilis) and Buffalograss (Bouteloua dactyloides). Blue Grama is one of the warm season grasses that dominate short grass prairies. The cool flowers look like eyelashes on narrow stems. It is drought tolerant and a good alternative for lawns, as is Buffalograss.

Peer down into this thick grass that seldom grows over 5 inches tall to discover the male plants and female plants. The females produce hidden burs that look like miniature sandburs, but these are small and not prickly. The hardy robust Buffalograss is another grass with dense roots used sod house construction. The short grass prairie occupies a thin stretch within the Great Plains which includes the Oklahoma Panhandle. Mining and energy exploration are decimating these unique prairies of North America.

Mixed-grass prairies are ecotones or areas between the tall grass and short grass prairies. They actually have the largest diversity of all prairies, or as one could say: the best of all prairie worlds. Western Oklahoma is home to our mixed-grass prairie, but the band extends from central Texas to Canada.

Grass seeds nourish turkeys, quail, finches, doves, sparrows, juncos and other birds. Deer and rabbits munch on the leaves, and the grasses provide nesting places, shelters and protection for wildlife. The native grasses have adapted to this area over hundreds of years. Their thick roots penetrate deep into the soil, loosen soil particles and help control or prevent erosion. The Texas USDA Natural Resources Conservation Service technical bulletin puts it so well: “Native plants are intrinsic to the overall resilience and stability of a region and are a critical component of the numerous food and energy cycles that maintain its biological diversity.”

Don’t forget your hummingbirds.