Rock Garden Quarterly Spring 2012 - (Page 150)

Liatris spicata is the characteristic species for the prairie. Note the tall trees embracing the site. in prehistoric lakes, forming new soil at the southernmost edge of the glaciers; Jennings is located at this edge, about 45 miles north of Pittsburgh. Changing climate conditions resulted in a warm, dry period, which allowed prairie plants to colonize the Midwest into Pennsylvania. Gradually the climate became cooler and wetter, more closely resembling the weather today. Eventually, through succession, forests replaced all but a few prairie sites in Pennsylvania. Otto Jennings discovered the site in 1905 and was able to convince the Western Pennsylvania Conservancy of its merit, preserving a relict 20 acres, the only publicly protected prairie ecosystem in the state. It is now managed by the Department of Conservation and Natural Resources. The Jennings Prairie remains due to a thick layer of impermeable clay underneath a thin layer of soil that prevents most tree species from becoming established. Plants and animals that do live on the prairie must tolerate shallow soils, fluctuating periods of drought and 150 Rock Garden Quarterly Vol. 70 (2)

Table of Contents for the Digital Edition of Rock Garden Quarterly Spring 2012

Geoffrey Charlesworth Writing Prize
2011 Photo Contest Winners
2012 Photo Contest Announcement
Seven Unheralded Axioms of Rock Gardening
Rock Gardening from Scratch: Vegetative Propagation - Understanding Cuttings
Newfoundland's Southern Limestone Barrens
William J. Dress, 1918-2011
DNA and the Changing Names of Plants ... and Making Sense of the Dicots
Jennings Prairie
Carl Gehenio, 1922-2011
Rock Gardening Roots
Plants that Dazzled me in 2011
Phipps Conservatory
Rock and Ink Struck into Flowers - A Response
Bulletin Board
2012 - Eastern Study Weekend: October, Pittsburgh - Registration form and details

Rock Garden Quarterly Spring 2012