Smooth purple coneflower is a perennial herb notable for its tall, smooth stems and striking conical flower heads. A distinctive characteristic is its pale pink to pale purple petals, which gracefully recurve as they mature, circling around a spiky, orange-brown central cone. Thriving in well-drained prairies, this plant has adapted to attract pollinators, while its deep taproot system enables survival in drier conditions.
I. Appearance and CharacteristicsÂ
Echinacea laevigata, the smooth purple coneflower, is a federally listed threatened species of plant found in the Piedmont of the eastern United States. Most populations are found on roadsides and other open areas with plenty of sunlight, often on calcium- and magnesium- rich soils.
Echinacea laevigata is a rhizomatous perennial herb that resembles its close relative, the common echinacea (Echinacea purpurea). The two can be told apart by the leaves, which are cordate (heart-shaped) in the common species. E. laevigata grows up to about 1.5 meters (5 feet) in height with a mostly naked, smooth, leafless stem. Any leaves are roughly lance-shaped. On top of the stem is a flower head containing narrow pink or purplish ray florets up to 8 centimeters (3.2 inches) long.
The florets droop away from the center of the head. The small, tubular disc florets in the center are dark purple. Blooming occurs in May through July. The fruit is an achene about half a centimeter long which is likely dispersed by birds and small mammals that collect them for food. Some vegetative reproduction has been observed with more than one stem coming from a shared rhizome or aboveground rosette of leaves.
The natural habitat for Echinacea laevigata is sunny openings in forested habitat. Open areas of this kind were made by wildfire, fires set by Native Americans, and the grazing activity of animals. The plant’s preferred soils are rich in calcium and magnesium, and include limestone and marble, gabbro, and diabase. Plants that share the habitat included eastern red cedar (Juniperus virginiana) and rattlesnake master (Eryngium yuccifolium).
There are several species of oak, but these are stunted allowing sunlight to reach the understory. When human impacts began to reduce the amount of forest habitat remaining in the region, the plant survived in other open, sunny habitat types, such as cedar barrens, clearcuts, roadsides, cleared areas around utility equipment, and limestone bluffs. Two-thirds of the populations known since the plant was first discovered are now gone.
The plant is pollinated by a number of insects, including honeybee (Apis mellifera), bumblebees (Bombus spp.), the bees Psithyrus citrinus and Xylocopa virginica, a number of butterflies, and Lygaeus kalmii, a bug.
II. How to Grow and Care
Sunlight
Smooth purple coneflower are long-day plants, preferring plenty of sunlight. During blooming, 14-16 hours of sunlight per day should be ensured for 7-8 weeks. For optimum posture and a maximum number of flowers, smooth purple coneflower should be planted in a place with at least 5 hours of full sun per day. The plant can adapt to partially-shaded environments, but the stem posture may become twisted in the search for adequate sunlight.
Temperature
Smooth purple coneflower thrive in hot and dry climates and adapt to various temperatures and humidity fluctuations. The plant does not perform well in very humid climates or in rainy areas with wet soil. In colder areas, it should be protected during winter during its first year. For better growth, maintain temperatures of about 16 to 24 ℃ during the day, and about 10 to 16 ℃ at night. High temperatures, preferably 21 to 24 ℃, are required for germination. It can germinate after 2-4 days.
Watering
Although smooth purple coneflower are usually regarded as drought-resistant plants, they form a better posture when regularly watered. Smooth purple coneflower need to be watered daily in the early period after planting, then watering should be gradually changed to once or twice a week.
Soil
Smooth purple coneflower planted in gardens prefer fertile, well-drained, neutral, sandy soil with a suitable pH value of 6.5-7.0. With fewer soil requirements than other plants, they can thrive in a variety of soil types, including rock and clay soil. However, smooth purple coneflower do not like humid or silty soil and grow best on fertile soil rich in humus.
Fertilizing
Smooth purple coneflower grows better in soil with sufficient nutrients, but too much fertilizer will weaken their stems and make them spindle. Add long-acting, slow-release fertilizer to the flowerpot soil during planting. After planting, fertilize them 1-2 times a week and supplement them with 0.05% magnesium sulfate 1-2 times as needed to prevent magnesium deficiency. Additionally, apply chelated iron 1-2 times to prevent iron deficiency. Compost can be used to cover the plant each spring to provide the nutrients needed for the healthy growth of leaves and flowers.
Planting Instructions
It is generally recommended to sow seeds in spring or autumn. Soak seeds in warm water for 20-30 min before sowing, then place them in hot water at 55 to 60 ℃. Maintain this water temperature for 10-15 min. Then, add cool water to drop the temperature to 25 to 30 ℃, and soak seeds for 8-10 hours. This speeds up seed germination and disinfects them.
Select well-drained and air-permeable soil, and apply a layer of fertilizer to it in advance. Before sowing the seeds, mix them well with a small amount of fine soil, and drop them evenly on the fertilized soil. Cover them with a layer of soil and slowly water them until it is sufficiently wet. Irrigate with a small amount of water so as not to flood the seeds together to prevent an uneven distribution of seedlings. The seedlings of smooth purple coneflower will usually break out of the soil about 8 days later. When the temperature is maintained at 22℃, the seedlings grow up in about 15 days.
When three branches grow out of the seedlings, and they are about 10 cm tall, the dense seedlings can be transplanted into individual flowerpots. Use 15 to 15 cm flowerpots and put one seedling in each pot. Make a culture soil by mixing 1/3 organic fertilizer, 1/3 garden soil, and 1/3 sand. After the seedlings are all transplanted to flowerpots, the soil should be compacted and watered sufficiently and flowerpots should be placed in cool places. 7-10 days later, move smooth purple coneflower to places with sunlight so they can grow normally.
Pruning
Pruning smooth purple coneflower in spring will make them denser and bloom for a longer period of time. Removing deadheads and dead leaves is the main goal of pruning. Removing deadheads will help the plant bloom throughout the summer, and each flower will last for weeks. The flowers will begin to bloom from the top of the stem, and more lateral branches and buds will form along the stem as the first flowers at the stem tip wither.
Propagation
Smooth purple coneflower can be propagated by sewing or cutting. Refer to the above text for the sowing method. For cutting, cut a branch about 5 cm long in spring, and retain 2-4 leaves. Remove the branch tip, cut under the node, and insert it into the soil immediately after cutting. Alternatively, you can divide the plant in spring and autumn. Separate it from the rhizome with a knife, and divide it into several plants. On average, you can leave each plant with 4-5 small buds and plant them in prepared soil.
Pests and Diseases
Plants are relatively pest resistant if cultural preferences are met but Japanese beetles and leaf spot cause occasional problems.
III. Harvesting and Storage
Smooth purple coneflower that grows from seeds usually bloom in the second year. When the buds begin to bloom, they can be harvested. The stem should be cut with sharp scissors from the bottom set of leaves. Remove the leaves from the stem after harvesting and remove the extra buds behind the flower heads to avoid excessive consumption of nutrients and water.
