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Coneflowers |
Echinacea purpurea Rubinstern - an"improved" purple coneflower seed strain (also sold as 'Ruby Star,' the English translation |
(above) Echinacea pallida (pale coneflower) with Helianthus slaicifolius (willowleaf sunglower) (right) Echinacea tennesseensis (Tennessee coneflower) with Oputia cactus. |
(left) Echinacea paradoxa var. paradoxa (yellow purple coneflower)with Monarda didyma (bee balm) (above) Coneflower hybrids and Chicago BOtanic Garden trials. |
Echinacea X 'Orange Meadowbright' |
Echinacea X 'Sundown' |
Echinacea X 'Harvest Moon' |
There are very few native plants with wider appeal than the coneflower (Echinacea spp). This uniquely North American genus of ten species epitomizes the meadow or prairie wildflower. In general, coneflowers are easy to grow in sunny, well-drained soil and the large daisy-shaped blooms remain colorful for at least a month. The plants grow from a woody crown, sending up first a tuft of basal leaves followed by leafy flower stems that rise up in mid-summer. Each stem is topped by one large bloom that can be as much as 4 inches across and once the first bloom begins to fade others grow from small side branches to take its place. Like other members of the aster family, Echinacea flowers are technically inflorescences made up of many small flowers serving one of two functions. Each petal or ray is really a single flower with five petals fused into one. The ray flowers form a ring around the central cone, which is also composed of many individual flowers that have no petals. The division of labor has particle consequences for pollination and seed set. The rays are sterile, functioning merely as advertisement for the less noticeable fertile flowers that make up the cone. These later produce nectar and pollen as well as seeds. A bee or butterfly cannot help but notice the ring of large, colorful ray flowers as it passes, and the cone |
provides a perfect lading pad foe the insect as it comes in to investigate. What the bug finds is a host of little, nectar rich blooms packed in together - a sort of one stop shopping that is very appealing. Rather than wasting energy flitting here and there, the bee or butterfly can settle in and drink from a bunch of flowers at once. When you plant coneflowers, the butterflies and bees are sure to follow. |
This combination of colorful advertizing and concentrated, easily accessible flowers has made the aster family one of the most successful and diverse in the world. However, the coneflowers appear to be a fairly new member of this large family as most of the species are pretty similar in leaf and flower shape and color. Coneflowers likely evolved fairly recently during the drying of the North American climate during the Pleistocene that allowed the development of prairie grassland habitat from the Southeastern US to the western mountains. The typical color of the bloom is light lavender with a deep red or black cone bristling with yellow or red knobs (these knobs or bristles likely aid pollination by providing scaffolding for the pollinator to crawl on then discourage predation of seeds by birds). |
There are two basic leaf types in the genus - one characterized by a 2-3 inch wide, ovate blade with a rounded or heart-shaped base and the other by a narrow (<1 inch) wide) linear leaf. The narrow-leaved species tend to grow in drier habitats than the two wide-leaved ones (E. purpurea - purple coneflower, which is found in the prairies west of the Appalachians and E. laevigata - smooth purple coneflower, which is a rare species from the eastern side of those same mountains). The most widespread of the narrow-leaved species is E. pallida (pale coneflower from the prairies east of the Rocky Mountains. It is closely related to the smaller E. angustifolia (narrow-leaved purple coneflower) which grows on both sides of the Rockies. There are several other related species, notable E. tennesseensis (Tennessee coneflower), which is very similar to E. angustifolia but restricted to dry, rocky prairie remnants on the Cumberland Plateau of Tennessee. Like most coneflowers, it is adapted to rather parched, fire-prone grasslands. From a horticultural point of view this is important as most of the species resent wet soils and poor air circulation around the leaves and crown of the plant. They have large, fleshy taproots that burrow deep in search of moisture and act as a food pantry to help the plant recover after drought or the frequent fires that sweep through their habitat. Taproots resent disturbance, rot easily if drainage is poor, and generally make plants more difficult to transplant and cultivate. The exception in this genus is E. purpurea, which prefers damp or even wet prairies and as a consequence has evolved a more forgiving fibrous root system that functions much better in this type of soil. From a functional point of view, purple coneflower is a much easier and forgiving plant to cultivate and it is no wonder that it has become the unquestionable favorite among gardeners. It has a further advantage in that its ray petals are wide and flat unlike the narrow or curled rays of the other species. The rays of wild plants point downward much like the feathers of a badminton shuttlecock, though breeders have selected forms which hold their rays parallel to the ground for flatter appearance. Tennessee coneflower is the only species with rays that naturally orient lightly upwards, and breeders have crossed this one with purple coneflower to yield hybrids with even flatter blooms. |