<b>Trees, Ornamental & Bedding Plant:</b> Coneflowers

Until about five years ago, most coneflowers found in gardens were selections of Echinacea purpurea and were purple, pink or white.

 Recent breakthroughs in breeding have introduced an exciting palette of colors, sizes and garden performance to this group of perennials.

This breeding has unleashed an imaginative array of cultivar names – “Fragrant Angel,” “Fatal Attraction,” “Twilight” and “Coconut Lime” to tempt the gardening public.

Progress is occurring at such a rapid pace that cultivars considered novel in color, size or form several years ago, are now being overshadowed or replaced by the newest introductions. Contractors will see additional innovation on the horizon based on this wave of new introductions.

The new hybrid coneflowers appear to perform best in full sun and well-drained, moderately fertile soil that is slightly acid to slightly alkaline (pH 6 to pH 8).

In the landscape. Although generally problem free, coneflowers are susceptible to aster yellows, a disease that causes distorted growth and deformed flowers. It is spread by the aster leafhopper and is best managed by promptly removing and discarding the infected plants.

Coneflowerss’ qualities make them exceptional garden perennials include large, daisylike flowers, ease of cultivation, long bloom period, drought and heat tolerance, and attractiveness to butterflies and bees. They are valuable additions to the intimate city garden, mixed perennial border or naturalistic country meadow.

Some excellent garden companions include tickseed (Coreopsis verticillata), early goldenrod (Solidago juncea), sweet goldenrod (Solidago odora), spike gayfeather (Liatris spicata), garden phlox (Phlox paniculata), scarlet beebalm (Monarda didyma), Joepyeweed (Eupatorium fistulosum), black-eyed Susan (Rudbeckia fulgida), butterfly weed (Asclepias tuberosa), Stoke’s aster (Stokesia laevis) and grasses such as little bluestem (Schizachyrium scoparium) and broomsedge (Andropogon virginicus).

Hybridization and selection
The discovery that coneflower species readily hybridize when brought into cultivation resulted in new cultivars with an exciting range of variation. The inclusion of the only yellow flowered species, E. paradoxa, in breeding programs has resulted in hybrids that have dramatically broadened the color range available to gardeners. New cultivars display petals in a tantalizing array of colors including butter yellow, gold, orange, mango, salmon, rose red and even lime green.

A number of hybridizers have concentrated their efforts on selections from the white and magenta-purple flowered E. purpurea. These selections have resulted in more compact, superior branching plants, selections with creamy-white variegated leaves and plants with double, pompom flowers. Selections have also been made for width, length and degree of overlapping petals, horizontally held petals, number of petals, stem color ranging from typically green to purple-black and cone color from yellowish orange and green to reddish black.

Evaluations
Mt. Cuba Center, located near Wilmington, Del., (USDA Hardiness Zone 7A/6B) conducted a three-year evaluation project (2007-2009) involving five species and 43 cultivars of coneflowers to determine their desirability for garden use in the mid-Atlantic region based on their ornamental attributes, adaptation to environmental conditions and resistance to insects and disease. The goal was to recommend superior taxa based on the following observations: floral display (flower color, inflorescence size, flower coverage, bloom period); habit (height, width, foliage quality, habit quality – need for staking or pinching); winter hardiness, cultural adaptability; and disease and pest resistance.

Maintenance included watering to establish the plants and as needed in times of drought, periodic weeding, and minimal dead-heading and staking. The beds were not fertilized, pesticides were not applied and the plants were given no winter protection.

Highly recommended plants
Echinacea ‘CBG Cone 2’ Pixie Meadowbrite is a charming, extremely floriferous, compact selection that grows approximately 22 inches tall and 24 inches wide. The 2½- to 2¾-inch wide, flat-petaled flowers are a vibrant rosy-pink and contrast nicely with the showy reddish-brown cone.

It is hardy, drought tolerant, long-lived, disease and pest resistant, has a compact, clumping habit and doesn’t need staking.It offers a striking floral display and has a pleasant fragrance.

E. purpurea ‘Pica Bella’ has an upright, bushy habit growing approximately 24-33 inches tall and equally as wide. The clean, medium green, lanceolate foliage remains full at the base and drapes the stems.

Flowers are abundantly produced on dark, multi-branched stems. The vivid pinkish-magenta flowers are 3½-4 inches wide, and the plump, broadly conical cones are vibrant orange with each bristle tip appearing to have been dipped in red paint.

It has a sturdy, vase-shaped habit and is vigorous and needs no staking. It is a prolific bloomer; uniquely shaped and vividly colored flowers. It is disease and pest resistant, and tolerant of drought and heat.

E. purpurea Elton Knight is an upright plant growing 30 inches tall and 24 inches wide. The clean, dark-green foliage is held horizontally and densely arranged throughout the plant, giving it a busy habit.

Flowers are brilliant magenta, 4 inches wide with attractively broad petals held horizontally to just below, and gently overlapping. The reddish-orange cone provides a striking contrast to the vibrantly colored petals.

It has a great compact, upright habit. No staking is required. It has multi-branched plants, with abundant blooms above foliage. It is disease and pest resistant.

E. purpurea Fatal Attraction is statuesque with an upright, columnar habit growing approximately 36 inches tall and 30 inches wide. This selection displays 3- to 3½-inch wide, vivid purplish-pink flowers atop deep-burgundy to nearly black stems.

The petals are held slightly above horizontal and contrasts with the reddish-orange cone. The plant has floriferous, eye-catching flower color. Flowers are held well above the foliage and have a sturdy, tight habit. It needs no staking, and is pest and disease resistant.

A) Echinacea Pixie Meadowbrite. B) E. purpurea ‘Coconut Lime’ received high ratings at the trial in the uniquely shaped flowers category. C) Echinacea ‘Sunrise’ is a hybrid that performed well in the yellow category. D) E. purpurea ‘Pica Bella’. Photos: Mt. Cuba Center

Jeanne Frett is the horticultural research manager at the Mt. Cuba Center in Greenville, Del.