Known for its pinkish-purple, daisylike blooms with hanging petals, the purple coneflower (Echinacea purpurea) belongs to the aster family and is easy to care for, whether grown in the ground or in a container. Hardy in U.S. Department of Agriculture plant hardiness zones 3 through 9, this drought-tolerant perennial grows best in full sun and fast-draining soils. Container-grown purple coneflowers will bring summer color to decks, patios and porches.
Pour 2 to 3 inches of crushed gravel into the bottom of a 2- to 3-gallon plastic pot. Fill the pot one-half full of fast-draining potting soil. Tamp the soil down slightly to remove air pockets. Add addition soil if needed to keep the pot one-half full. Use a pot that has drainage holes.
Remove the purple coneflower plant from its pot. Gently massage the root ball's bottom, spreading the roots outward. Place the plant in the center of the pot. Add or remove potting soil underneath the plant, if needed, to position the top of the root ball 1 1/2 to 2 inches below the pot's top.
Add 3 inches of soil to the pot at a time. Tamp the soil gently, yet firmly, around the plant's root ball. Repeat this until the soil level is even with the top of the plant's root ball. Do not plant the coneflower deeper than it was previously growing.
Place the pot in an area that receives full, direct sun in the morning and filtered shade in the afternoon. Fill the pot two to three times with water from a watering can or garden hose. Allow the excess water to drain out the bottom holes. Discard standing water in a drainage tray if you keep one underneath the pot. Do not allow the soil to become soggy.
Water the coneflower when the top 1 inch of soil becomes dry. Add water directly into the pot at the plant's base. Avoid splashing the plant's leaves as much as possible. Water the plant only in the morning to allow wet foliage time to dry before nightfall.
Fertilize the coneflower every seven to 10 days with a 10-10-10 water-soluble fertilizer. Mix the fertilizer at a rate of 1 tablespoon per 1 gallon of water. Pour 1 1/2 to 2 cups of the fertilizer solution into the pot at each application.
Deadhead the coneflower once the blooms begin to drop their petals. Cut through the bottom of the flower stem with a pair of pruning shears. Removing the spent flowers will direct the plant's energy into continued growth and flower production instead of seed production.
Check the plant's leaves each time you water for signs of insect damage or the presence of aphids, whiteflies or leaf miners. Spray small populations of these insects off with a steady stream of water. Spray heavily infested plants with neem oil or insecticidal soap to eradicate these pests.
Divide and repot the plant every three to four years in spring, once new growth starts, to rejuvenate it and encourage continued healthy growth.
Move the plant to an area with consistent temperatures of 40 to 50 degrees Fahrenheit in the late fall and winter, once the plant's growth begins to slow. Cut back the foliage to soil level once it turns yellow and dies back. Water the pot only when the top 3 inches of soil becomes dry. Move the pot to a warmer area with temperatures of 60 to 70 F in spring, once new growth begins.
Things You Will Need
- 2- to 3-gallon plastic pot
- Crushed gravel
- Potting soil
- Watering can or garden hose
- 10-10-10 water-soluble fertilizer
- Pruning shears
- Neem oil or insecticidal soap
- Trowel or knife
- University of Florida IFAS Extension: Echinacea Purpurea: Purple Coneflower
- Cornell University: Coneflower, Purple
- University of Vermont Extension System: Growing Perennials in Containers
- University of Maryland: Production of Purple Coneflower as a Cut Flower
- The Contained Garden: The Complete Guide to Growing Outdoor Plants in Pots; Kenneth A. Beckett
- Andy Sotiriou/Photodisc/Getty Images