The native plants of Illinois are well-adapted to the climate and the wide variety of landscapes found across the state. Illinois is situated in hardiness zones 4b to 6b. Landscapes in Illinois range from cliffs and forests in the south, to prairies in the central part of the state, and savannas and wetlands in the north. No matter what part of Illinois you call home, there is a native plant suited to the landscape.
The white oak (Quercus alba) became the state tree of Illinois in 1973. The state tree had been the native oak and the change was to clarify which Illinois native oak tree. White oak is native to north, central and southern Illinois, found on wooded slopes and in dry, upland woods regions. The white oak can grow 60 to 80 feet tall and just as wide. When the leaves are new, they're a gray or bright green, changing to a muted blue-green color when the tree is fully mature. In the fall, the foliage is purple-red or wine-red, bringing color to the winter landscape.
Common ninebark (Physocarpus opulifolius), also called Atlantic ninebark, is a deciduous shrub with arching branches that is 5 to 10 feet tall and wide when mature. This shrub is native to north, south and central Illinois. Large clusters of pure white or off-white flowers bloom in early summer. Fruit takes the place of flowers in mid-to-late summer. Common ninebark is a hardy shrub, able to tolerate almost any type of soil. Use this shrub in hedges, along a border or as a stand alone specimen plant.
Cardinal flowers (Lobelia cardinalis) are a must-have in a wildlife garden. The native Illinois plant is pollinated by hummingbirds, who seek the nectar in the flowers. The bright red tubular flowers bloom from May to October and grow 3 to 6 feet tall. It thrives along the banks of streams, ditches and ravines. Areas with moist soil such as roadsides, meadows and pastures provide cardinal flowers with the rich soil they need.
The wood lily (Lilium philadelphicum) is an Illinois native perennial with bright orange or orange-red flowers. The bottom of the petals in the center have dark colored spots that are purplish or purplish-brown. It blooms in July and August and attracts hummingbirds that feed on the flower's nectar. The soil needs to be rich with organic matter and well-drained. This type of soil is typically found on prairies and near forests.