Introduction

As part of our continuing efforts to restore the hayfields of Ivy Creek to native grasslands, Ivy Creek Foundation periodically conducts controlled burns of some of the fields at the Ivy Creek Natural Area. Our most recent burn was on April 2, 2008 of the North Field, which is surrounded by the Field Trail. This year’s burn was conducted with The Nature Conservancy. In the past, ICF has also worked with the Virginia Department of Forestry, the Albemarle County Department of Parks and Recreation and the City of Charlottesville Parks Division to ensure safe procedures.

Burning every two to three years is the management strategy of choice for native grass fields to retard successional growth of woody plants. The initial burn removes the thick thatch layer that has built up over years of mowing, which prepares it to be sown with three species of native grasses: Indian grass, Big Bluestem and Little Bluestem.

Warm-season grasses are fire-adapted. The growing tissue is below the litter layer along an underground stem, well-protected from the heat of the fire. Furthermore, as summer rains decrease and the threat of fire increases, these grasses transfer organic compounds from leaves to storage in the root system, sequestering them from loss in a fire. This network forms a thick sod and produces a dense stand of new shoots (tillers) the next year.

Early spring is an optimal time to burn to avoid the active nesting season for ground-dwelling birds and other wildlife. In addition a March fire precedes the growth of herbaceous forbs that will add to the biodiversity of the grassland — at the same time it removes the competing shade of the tall grasses allowing sunlight to warm the ground earlier in the season giving the grasses and forbs a jump start on new growth.

Photos from previous years:

• South field, 2002
• North field, 2003
• North field, 2008

Native Grasses at the Ivy Creek Natural Area

From the Osage Hills of Oklahoma to the sandhills of Nebraska, Big Bluestem is the dominant plant in the tallgrass prairie. But Big Bluestem is not indigenous to the Great Plains. Its origin was in the successional grasslands of the eastern states until largely replaced by farmers with bluegrass and introduced fescue which are ideally suited to the pasturing of European cattle. These latter grasses are cool-season grasses, that is, they start growing early in the year, providing good grazing so that cattle can gain marketable weight more rapidly.

Big Bluestem, along with Indian Grass and Little Bluestem, which have been reseeded at Ivy Creek, are warm-season grasses. These species do not begin growing until the time of summer rains and do not flower until summer is almost over.

Warm season grasses are well-adapted to drought and fire. They have an obligatory symbiotic relationship with mycorrhizal fungi which grow into their root cells and expand through the soil increasing the zone of influence of the fibrous root system, facilitating water and nutrient uptake. More importantly they have an auxiliary photosynthetic system that is not found in the cool-season grasses, allowing them to store carbon dioxide from the air in an organic compound during the heat of the day when it closes the pores in its leaves to conserve water. As summer rains decrease and the threat of fire increases, warm season grasses transfer organic compounds from their leaves to storage in the root system, sequestering them from loss in a fire.

Indeed, the management of warm-season grasslands is by periodic fire rather than mowing in that woody plants with their growing tissue at the tips of the branches are killed by the fire while warm season grasses remain as secure as b’re rabbit in the briar patch.

Big Bluestem
Andropogon gerardii
Sometimes called the King of native grasses, Big Bluestem can grow up to eight feet tall with long thin flowers radiating from the top of the stem, thus its common name of “turkey foot”. It displays an array of color throughout the summer and fall, from steel gray-blue in the summer to brown, red and purple in the fall. Root systems extending 12 feet down give the plant an extraordinary capacity to withstand drought and extreme temperature.

Little Bluestem
Schizachyrium scoparium
Little Bluestem is an unfortunate name for this striking grass because it is neither little not particularly blue — except when the shoots come up in early summer. By the time it flowers, it has turned a rich mixture of tan and brown with wine-red branches. Probably the most abundant native grass and known as an old-field invader, Little Bluestem is also an excellent forage plant.

Indian Grass
Sorghastrum nutans
Competing with Big Bluestem for height, Indian Grass is distinctive for the small twisted bristles on its slightly fuzzy, late summer flowers. The inflorescence is tall and narrow and turns a shining golden brown. The fruit, six to 10 inches long, appears as copper-colored plumes, making this a very attractive plant.

Broomsedge
Andropogon virginicus
A common grass at Ivy Creek, Broomsedge is very coarse and turns a beautiful bronze-orange in the winter. It is leafier than other grasses and the flower stalk, surrounded by silvery white hairs, is tucked inside the leaves. Although the plant is not good livestock forage, it has long been the backbone of Virginia quail habitat.

–excerpted from the Ivy Creek Foundation newsletter, Spring 2002. For more information on this and other Foundation news, join ICF!