Gardeners in different parts of Colorado face different challenges. Colorado has a total of six hardiness zones from the very cold zone two, where winter temperatures can get to 50 degrees below zero, to the warm zone seven, when the winter temperatures do not get below zero. Most of the state is from zone three to zone six, with just a small portion at the two extremes. Not all of the flowers for Colorado will grow in all areas, but there is something for everyone.
Large beardtongue (Penstemon grandiflorus), also known as large-flower beardtongue and large-flowered penstemon, is a member of the figwort family. The plant grows from 2 to 3 feet tall with blue-green leaves and ping or blue-lavender tube-shaped flowers that grow horizontally the length of the stem and bloom in May and June. Plant large beardtongue in full sun and in dry, sandy soil. Large beardtongue is hardy from zones three through nine.
Smooth Solomon's Seal
Smooth Solomon's seal (Polygonatum biflorum) belongs to the lily family. The plant, also known as Great Solomon's-seal, grows from 1 to 5 feet tall with bright yellow-green, oval shaped leaves and small white, yellow, green or brown bell-shaped flowers that grow in pairs that bloom from March through June. The flowers are followed by small blue or black, unedible fruits. Plant smooth Solomon's seal in partial or full shade and in a soil that is moist to dry. Smooth Solomon's seal will attract both birds and butterflies, does well planted under large trees and is hardy in zones three to nine.
Rose campion (Lychnis coronaria) is also known as mullein pink and Dusty Miller. The plant grows from 2 to 3 feet tall and 1 to 3 feet wide with 2- to 4-inch long, oval shaped leaves on the stems and 4- to 6-inch long leaves at the base. The small, long-stemmed, rose-pink or purple flowers do not usually appear until the second year, last for one day and are replaced by new blooms. The plant dies in the third year but is replaced by new seedlings. Plant rose campion in full sun and moist to dry soil for the best results. The plant is hardy in zone five through eight and grows as an annual in zones three and four.
Leopard's Bane (Doronicum 'Little Leo') is a member of the daisy family and grows from 10 to 12 inches with an equal spread. The plant produces deep-green leaves and bright-yellow flowers that bloom from mid-spring through early summer. Plant Leopard's bane in partial shade and a moist soil for best results. The plant is used in rock gardens and as an edging and is both deer- and rabbit-resistant. Leopard's bane is hardy in zones two to nine.