The Black-Eyed Susan, botanically known as Rudbeckia hirta, is a popular North American native wildflower often grown in home gardens. Its bright golden-yellow petals surround a distinctive dark brown center, giving it the common “black-eyed” name. These plants are appreciated for their toughness, typically being sun-loving and able to withstand periods of dry weather once established. As an annual or biennial plant, the Black-Eyed Susan is easy to grow from seed and readily self-sows.
Preparing the Planting Site and Timing
Selecting the correct time and location for sowing your seeds is the first step toward successful growth. Black-Eyed Susans require a site that receives full sunlight, meaning at least six hours of direct sun exposure each day to encourage robust flowering and prevent leggy, weak stems. While they can tolerate partial sun, the bloom density will be noticeably reduced in shadier spots.
The optimal time for planting depends on your climate. For spring sowing, wait until after the last expected frost date when the soil temperature has warmed to around 70°F for the best germination rates. Alternatively, you can sow seeds in late fall to allow them to go through a natural cold stratification process over winter, resulting in spring germination.
Black-Eyed Susans prefer average to poor soil that is well-draining. Highly enriched or fertile soil can cause the plants to produce more foliage than flowers, leading to excessive, lanky growth. Before planting, simply loosen the top inch or two of soil and clear away any existing weeds.
Sowing Seeds Directly Outdoors
Because the seeds of Rudbeckia hirta are tiny and need light to successfully sprout, they should be surface-sown directly onto the prepared soil rather than buried deeply. Press the seeds gently into the soil surface to ensure good seed-to-soil contact.
If you prefer a small amount of cover, use only a very light dusting of fine soil, no more than 1/8 inch thick. Sowing the seeds thinly is ideal for managing future growth, but you can also broadcast them more thickly and plan to thin the seedlings later. A general guideline is to aim for a final spacing of 12 inches between mature plants.
Immediately after sowing, the planting area must be watered gently using a fine spray or mist to avoid displacing the tiny seeds. The goal is to settle the seeds and moisten the top layer of soil without creating puddles or washing the seeds away. Maintaining this initial moisture is important for surface-sown seeds to prevent them from drying out before they can germinate.
Post-Planting Care and Thinning
Consistent moisture is necessary immediately following the planting process to encourage germination, which can take anywhere from 10 to 45 days. Keep the top inch of soil consistently moist, but be careful not to overwater, as waterlogged conditions can cause the seeds or young seedlings to rot. Once the plants have grown and become established, they will be significantly more tolerant of dry conditions and will require less frequent watering.
Thinning the young plants is a necessary step to prevent overcrowding, which can restrict airflow and increase the risk of disease. Wait until the seedlings develop their first set of true leaves. Select the strongest-looking seedlings and gently pinch or snip the others at the soil line, leaving the remaining plants spaced about 12 inches apart.
The Black-Eyed Susan is a low-maintenance plant and typically does not require supplemental fertilization. Weeding should be done carefully around the young seedlings to eliminate competition without disturbing their shallow root systems.