Stachys' silvery leaves are perfect foils for plants with hot- or cool-colored blossoms. Conversely, betonies bring a casual formality to the border, herb garden, cottage garden or meadow. While lamb’s ears tends to decline during flowering, deadheading regenerates leaves and improves plant vigor.

Heavy-flowering Oenothera are healthy plants with winter hardiness, giving many of these

taxa five-star excellent ratings. Sundrops and evening primroses thrive in full sun but tolerate light shade. Oenothera speciosa may spread rapidly to become weedy in rich or highly fertile soils.

One of the most attractive aspects of fall-blooming anemones is their extended bloom period. It is not uncommon for these plants to bloom continuously for more than two months. A great fill plant for larger landscapes, anemones can out-compete smaller herbaceous plants in close quarters.

With few exceptions, Alchemilla prove to be good garden plants. The similarity of the cultivated species -- minor differences in leaves, flowers and habits -- allows gardeners to interchange them depending on availability.

Uneven moisture regimes can make the placement of plants in the shady garden an

all-or-nothing experiment. In these circumstances, a variety of dead nettles come to the rescue. From green, silver, yellow and variegated leaves to ground covers and upright habits, dead nettles offer ornamental versatility as well as a tolerance to a wide range of conditions.

Hardy geranium is a general term that is used to distinguish Geranium from its tender cousin Pelargonium, the colorful floral or bedding geranium. Many species, especially those with trailing habits, can be used on slopes, retaining walls and in containers. Several varieties can be grown together for continuous bloom from spring to autumn.

Few perennials have exploded onto the scene quite like coral bells, or Heuchera. Breeding has brought a variety of foliage shape and color and improved flower production to market. Look for coral bells with lime-green or amber-gold leaves, and abundant red or pink blossoms -- now available.

Barrenworts are tough, long-lived perennials that are an invaluable garden plant for the challenging environment of the Midwest -- their toughness and ability to compete with tree

roots make them a must-have in any shade garden, and Epimedium provides a variety of unique, colorful flowers and leaves in the spring and a backdrop of green waves throughout the remainder of the year.

While many artemesias in the study proved unsuitable for northern climes, planting artemisias in lighter soils with sharp drainage may reduce the potential for winter injury or loss of these plants, and allow you to add some texture and beauty to your perennial borders and rock gardens.

Bluestars prove to be hardy, low-maintenance perennials, giving three seasons of interest in the garden. Clusters of pale blue flowers top the upright stems in May and June before new stem growth covers the remaining flowers. For exceptional floral displays, try Amsonia tabernaemontana var. salicifolia and Amsonia illustris.