JACKSON, Ohio - Lake Katharine State Nature Preserve is at its colorful best in late April and early May, perhaps into June.

The 2,000-acre preserve in Jackson County in southern Ohio is known as a spring wildflower preserve, one of the best in Ohio.

It is dominated by the colorful calico bush or mountain laurel.

The preserve's Calico Bush Trail is surrounded by massive sandstone outcroppings up to 150 feet tall where the mountain laurel is abundant.

The dense whitish-purple flowers reminded early settlers of the then-popular floral printed cloth known as calico.

Lake Katharine, widely hailed as one of Ohio's very best state nature preserves, is known for its lake, trails, cliffs, biodiversity and unusual plants.

The preserve's major attractions are 120-acre Lake Katharine, a man-made body of water, its Appalachian forests and three deep ravines.

The preserve features 5.5 miles of hiking trails: the 1-mile Calico Bush Trail, the 2.5-mile Pine Ridge Trail and the 2-mile Salt Creek Trail.

All three loop trails start in the same area in the eastern part of the preserve.

The western half of the preserve is off-limits to visitors and restricted to scientific research.

More species of plants have been recorded in Jackson County than any other Ohio county.

Lake Katharine features 20 plant species that are state listed or endangered, threatened or potentially threatened.

What makes the Lake Katharine State Nature Reserve so special is that it features southern plants found in very few other spots in Ohio, along with more common Ohio species.

The southern seeds were carried north from North Carolina into Ohio by the ancient Teays River that predated the Ohio River.

The result is plants like the round-leaf catchfly, flame azalea, Sampson's snakeroot, butterfly pea, Hercules'-club or devil's walking stick (a spiny shrub with black berries) and Canby's mountain-lover.

Many of the rare plants are at the northern limit of their range at Lake Katharine. But they are thriving in the sheltered hollows along Rock Run and Little Salt Creek.

Lake Katharine is also home to Ohio's finest collection of both bigleaf and umbrella magnolias.

Umbrella magnolias are listed as threatened in Ohio and are found only in Jackson, Hocking, Scioto and Vinton counties.

They are found along all three trails at Lake Katharine and are more abundant than the bigleaf magnolias.

The flowering bigleaf magnolia is found only at Lake Katharine in Jackson County and is listed as an endangered plant species in Ohio.

About 2,000 of the bigleaf magnolias are growing along the Salt Creek Trail, although most have not yet reached seed-producing maturity.

In fact, a sketch of the bigleaf magnolia is on the cover on the preserve's brochure/map. The mountain laurel is pictured inside the brochure.

The two magnolias have different leaves. Umbrella magnolia leaves taper at the stem and are slightly smaller than the bigleaf variety that has twin lobes at the base of the leaf.

In the spring, you can't miss the magnolias when the creamy white and fragrant petals unfold. Later they will drop seed pods that look like pine cones.

In late autumn and winter, the giant-sized fallen leaves will cover the flood plain.

The bigleaf has green buds; the umbrella, brown buds.

Lake Katharine features great plant diversity because it offers a range of different habitats: dry ridge tops, moist flood plains and cool gorges.

Oaks and hickories thrive on the ridges, hemlocks love the cool, moist ravines. Tulip poplars do well in the moist valleys. River birches thrive along the streams.

Rare plants along the Calico Bush Trail include mountain watercress, starflowers, puttyroot and stemless lady's slipper.

Ferns are numerous in cool, shady spots along the trail and at the base of the cliffs.

You can see lichen and moss along the Calico Bush Trail.

The Pine Ridge Trail runs along Rock Run and past sandstone cliffs with mountain laurel, blueberries and wintergreen.

At several points, you can peer down into deep, dark ravines that are off-limits to visitors who must stay on designated trails.

You will cross the 260-foot-long earthen dam that created Lake Katharine and visit the pine-covered ridges.

Salt Creek is the preserve's newest trail, completed in 1979 by the Youth Conservation Corps.

There are 150-foot-high sandstone cliffs, old Indian work sites and burial pits, abandoned drift mines and a former narrow-gauge railroad right of way along the trail.

The trail also features spotted salamanders in the spring and state-record-size magnolias and river birches.

You can also observe the Sharon conglomerate stone that forms the sandstone outcroppings. The conglomerate, formed 300 million years ago, includes smooth, round, white quartz pebbles.

Wildlife found at Lake Katharine includes wild turkey, white-tailed deer, beaver and bobcat, an endangered mammal.

Lake Katharine became a state nature preserve - thanks to the foresight and generosity of two long-time Jackson County business partners, Edwin A. Jones and James J. McKitterick, partners in the Globe Iron Co.

The preserve is named for Jones' wife, Katharine.

The two men bought the property in the mid-1940s. They built the dam across Rock Run and opened Camp Arrowhead, a youth camp, in 1947. It operated for 18 years.

The camp was last used by Girl Scouts in 1970. It was acquired by the Ohio Department of Natural Resources in 1976 and was dedicated as a nature preserve in July 1977.

It is one of the largest state nature preserves in Ohio.

Lake Katharine lies two miles west of the city of Jackson. Take State Street (County Road 76) west from Jackson for two miles. Head north on Lake Katharine Road (County Road 85) for two miles to find the preserve entrance, parking lot and trailheads.

The preserve recommends that visitors wear sturdy footwear, proper clothing and be aware of how long each trail is.

The trails might be closed temporarily by winter storms or seasonal flooding.

Written watercraft permits are required to boat on Lake Katharine. Limited to five boats per day. No motors are permitted. You can carry boats down a 110-foot slope to the lake and back up at the end of the day.

Hours: dawn to dusk.

For more information, contact Lake Katharine State Nature Preserve, 784 Rock Run Road, Jackson, OH 45640; 614-286-2487. The Internet site is http:// www.ohiodnr.com.