Hardiness zones are used to categorize which plants will do well in the weather of a particular location. The lower the number used, the more hardy the plant is, allowing for colder winter weather. Zone 5 flowers need to be able to withstand a winter temperature of between -20 and -10 degrees F. There are plenty of Zone 5 annual flowers, as they need to be replanted every year anyway. However, there are also many perennial flower plants that do well in the states with a Zone 5 climate.
Aster (Blue Autumn)
The deep blue to purple petals and yellow centers of the perennial, Aster (Blue Autumn), are quite striking. The flower has a daisy-type shape and the plant grows up to 20 inches tall. The aster prefers a full sun location with a moderate amount of moisture. This butterfly attraction blooms through autumn and cutting off dead flower heads will increase this plant's blooming time even more.
Bellflower (Pearl Deep Blue)
The Bellflower (Pearl Deep Blue) is a hardy perennial that grows between 6 to 8 inches tall. It loves a full sun location, but will grow in partial shade. In fact, if your area is known for very hot summers, planting the Bellflower in a part shade location is recommended. Give it a moderate amount of moisture to see its lovely cup-shaped blue petals from late spring to late summer.
Little white flower clusters fill the mature Candytuft (Tahoe) flower bush. Its mature height only reaches 10 inches at the most, but its spread can be as much as 24 inches. Because of its size, Candytuft (Tahoe) works well as an edging plant or a groundcover. This plant prefers moderate moisture and a full sun location. It's an early bloomer, mid to late spring, but it continues with a luscious green foliage through the summer months.
Black Eyed Susan (City Garden)
The Black Eyed Susan (City Garden) is a very hardy flower that will grow well in Zones 2 through 10. It's a smaller version of many of the other types of Black Eyed Susans, making it perfect for smaller gardens and container gardening. The daisy-like flower of this perennial plant, has golden petals and a dark brown center. It enjoys moderate moisture and does well in sun or partial shade. This one also attracts butterflies, which can only add to the beauty and enjoyment of your landscaping.
Daylily (Buttered Popcorn)
The name, Buttered Popcorn, says it all. This lily displays buttery-yellow 6-inch blooms during the summer months and the plant can grow to 32 inches tall. Besides the ability to survive a cold winter, this plant is also known for its immunity to polluted environments and poor and dry soil. It can also be grown near Black Walnut trees.