Black-eyed Susan (Rudbeckia hirta) is native to North America and is often seen growing wild on prairies. This perennial showy flower is a member of the aster family and blooms from midsummer into autumn. Growing 2- to 3-feet tall, the black-eyed Susan is best known for its 3- to 4-inch diameter flowers bursting into brilliant yellows, oranges and golds, with a prominent black center. This easy-to-grow plant is hardy in zones 3 to 10 and is ideal for colorful summer flower gardens.
Plant seeds indoors about six to eights weeks before the last frost so the seedlings will be ready for planting in the garden after the last frost has passed. Fill a seed tray with drainage holes to the rim with potting soil and water well until the soil is moist.
Sprinkle black-eyed Susan seeds evenly over the soil in the seed tray. Gently press the seeds into the soil but do not cover with more soil. Set the tray in front of a window, where it will get some light daily, although black-eyed Susans do not need excessive light to germinate. Keep the soil moist, but not soaking wet while the seedlings are growing.
Plant the seedlings that are approximately 6- to 8-inches tall outside in your garden area once the last frost has passed, usually around mid- to late spring. Choose a garden location that receives full sun daily with some afternoon shade in areas where the summer is extremely hot.
Work the ground by tilling or raking to loosen the soil. Amend with compost to give the soil good drainage. Black-eyed Susan plants can tolerate almost any type of soil, but do best in a well-draining soil.
Dig a hole for each plant that is the same size as the root ball. Space the plants about 1- to 1 1/2-feet apart. These plants can tolerate crowding well, so they can be planted closer together in groupings if you desire. They often look better in groupings than separately.
Water your plants consistently about two to three times weekly just to keep the soil moist. Adjust the amount of water needed according to how warm the weather is and how quickly the soil dries out. Using drip irrigation or a soaker hose works best for a deep watering.
Fertilize with a balanced fertilizer (i.e., 13-13-13) after planting. A slow-release formula works well. Fertilize once a year in the early spring before your flowers begin blooming.