Pennsylvania State University defines native plants as those growing in what became Pennsylvania before the arrival of the first Europeans. Natives thrive in the Keystone State's USDA Hardiness Zones, with winter temperatures as low as 25 degrees below zero. Providing food and shelter for native insects, birds and wildlife, they don't strip the soil of its nutrients. Whether magnificent shade trees or hidden forest herbs, they play essential roles in Pennsylvania's ecosystems.
Red maple (Acer rubrum) is common throughout Pennsylvania, growing in moist woodland soils and along streams. Some wild red maples grow taller than 100 feet. Cultivars for home gardens usually reach no more than 60 feet, according to the Lady Bird Johnson Wildflower Center.
Male trees have noticeable smoky red flowers between March and April, with females producing winged red seedpods--samaras--a few weeks later. Green summer leaves usually become vivid scarlet in autumn, accounting for the maple's name. Some trees, however, have yellow fall foliage. Even in winter, red maple's silvery bark makes it an attractive garden tree.
Plant red maple in full sun to part shade. It likes moist, slightly acidic soil. Red maple tolerates ozone and--to a lesser degree--sulphur dioxide air pollution. The trees' spreading, fibrous root systems may discourage other plants from growing near them.
A bushy perennial that grows up to 2 feet, butterfly weed (Asclepias tuberosa) grows in Pennsylvania's open woods and fields. This member of the milkweed family is topped with clusters of blazing orange flowers between May and September. Hummingbirds and butterflies, including Monarchs, flock to the blooms for their fragrant nectar. Deep green, lance-shaped leaves contrast with the blooms.
Plant butterfly weed in a well-drained, sunny or partly shady spot. Drought-resistant, it prefers sand but tolerates loam, clay and limestone-rich soils. Expect aphids to find the plants. Remove them, says the Lady Bird Johnson Wildflower Center, with a high-pressure blast of water. The plant's roots and sap are toxic if ingested.
Annual American bellflower (Campanulastrum americanum) grows wild in Pennsylvania's damp woods and along streams. Between June and August, the upper parts of its stems bear spikes of pale blue to purple flowers. Contrary to the plant's name, the blooms are flat and not bell-shaped, like those of other bellflowers. American bellflower makes an excellent addition to hummingbird or shade gardens. Plant it in a well-drained, partly shady spot. It grows up to 4 feet and likes moist, rich pH-neutral soil.