Plants typically found in the Appalachians and more northern climes have lingered along Swift Creek in Cary, North Carolina, since the ice ages when the Piedmont landscape was much different. Precipitous north-facing slopes at what is now Hemlock Bluffs Nature Preserve provide soil conditions and a cool microclimate that harbor several montane species.
Hemlock Bluffs Nature Preserve is named for the Eastern hemlocks (Tsuga canadensis) found here. These conifers are usually found more than 200 miles away at elevations around 2000 to 5000 feet in western North Carolina, even though the preserve’s highest point is under 450 feet. Some of the hemlocks in the preserve are hundreds of years old.
In 1976, the state of North Carolina bought 84.7 acres after lobbying by a group now called Friends of Hemlock Bluffs. In 1979, the land became a State Nature and Historic Preserve, included in the State Registry of Natural Heritage Areas. Today, Hemlock Bluffs is managed by the town of Cary and includes another 29 acres donated in 1986 by Tim Smith and 36 acres donated by Lochmere Highlands and Regency Park in 1988.
The heart of Hemlock Bluffs is the Stevens Nature Center, a complex hosting exhibits, programs, and facilities, built in late 1992 and named for benefactors Colonel William Walton Stevens and wife Emily Stevens. Many people start their visit at the center for background information on the hemlocks before hiking one of the preserve’s several trails.
The nature center has three gardens. In the courtyard is a Wildflower Garden with showy native plants that bloom over much of the year. Educational crafts and projects completed at the center are showcased in the Children’s Garden near the center’s classroom, with a focus on garden crafts and activities you can complete with your child. The Recycled Art Garden near the trailhead shows ways to repurpose household items into attractive plant containers instead of tossing these into the trash.
From the Stevens Nature Center, a system of trails, boardwalks, and overlooks allow visitors access to the area without disrupting the fragile micro-habitat. Mulched trails go in two directions, highlighting the preserve’s uplands and bottomland. The hemlocks can be seen at overlooks either way you go, though both require descending stairs to reach the overlooks.
To the left of the center, the longer Chestnut Oak trail (1.2 miles long) and Beech Tree Cove trail (.9 miles long) forms loops in the uplands. Chestnut oaks, canopy trees found on a few dry hills in the Triangle, mingle with hemlocks and have leaves resembling more common swamp chestnut oaks, which grow in the floodplain. There are longleaf pines, typical of the Sandhills, as well as shortleaf pines in dry areas. Beech and several oaks dominate in places. There will be a controlled burn in the uplands this spring, a program that began several years ago. The bluffs tower 80 feet above Swift Creek and mark an ancient fault line. The bedrock was formed by volcanoes 500 to 600 million years ago, but 220 million years ago faults formed, and quartz was laid down by hydrothermal activity. Quartz resists erosion, so the bluffs eroded less than the surrounding land, similar to the process that created Occoneechee Mountain in Hillsborough, North Carolina, another place where montane species persist in the Piedmont.
Besides the Eastern hemlocks, other montane or rare species in the preserve include the glossy evergreen groundcover galax, showy orchis, and yellow lady’s slipper orchids. Of 64 species of moss found in the Preserve, five are disjunct from the Appalachians and another four rarely grow this far east. Sweet pinesap, a rare saprophytic plant, has been seen here in the past, but not recently. In dry areas, shrubs include blueberries and sweetleaf. Unlike at the Triangle’s other remnant sites, you won’t fond native Rhododendrons here.
Going right from the Nature Center, the Swift Creek Loop Trail is just under a mile long and explores the floodplain. This trail includes some 100 stairs that must be taken both down to access the level floodplain trail and back up to return to the parking area. As you descend the stairs, note that on the hillsides, hollies and sourwoods are common understory trees, and a mistletoe sits high in a northern red oak. Forbs include heartleaf, pipsissewa, trout lilies, and Christmas ferns. Near the creek, there are some very large tulip trees and a few smaller loblollies, plus ash, ironwood, birch, elm, beech, red maple, and what could be umbrella magnolia. There is an extensive stand of a bamboo-like cane on the soggy ground.
The preserve teems with wildlife. Several salamander species live in the uplands and breed in seasonal pools here, including marbled, spotted, slimy, four-toed, dwarf, and redback salamanders. There are also rare spotted turtles. Several rare to endangered freshwater mussels, a madtom, and a waterdog live in the Swift Creek basin. A few decades ago a new crayfish was discovered here. The hoots of barred owls resound through the forest, one of 130 birds recorded in the preserve.
In 2010 and again in 2014, the Eastern hemlocks here were threatened by the hemlock woolly adelgid, an insect inadvertently transported to this country that is decimating Appalachian forests. Fortunately, the preserve was able to get rid of them in this limited area.
Not far away, Cary’s Harold D Ritter Park is north of Swift Creek and has a playground and athletic areas. The Swift Creek Greenway is also on the north side and is 3.1miles long, with plans for extensions upstream and downstream. This 10-foot wide trail is paved with recycled asphalt. The trailhead is in Ritter Park and sidewalks connect the two parks. The non-profit Triangle Land Conservancy’s 23-acre Swift Creek Bluffs Nature Preserve, a short distance downstream accessible from Holly Springs Road, protects a forest of massive beech with mountain plants, a rich assemblage of early flowers, and overcup oak swamp forest.
Featured image: Hemlock Bluffs / Bill Stice-Cary Parks
Michael Pollock is a freelance writer who gardens in Durham. He has written for publications such as Carolina Gardener, The News & Observer’s Durham News, Chatham County Line, and Carrboro Free Press.