Black-Eyed Susan in Zone 6A — Great Plains

Black-Eyed Susans are a classic for a reason, and they're right at home here on the Plains. Their bright, cheerful blooms bring a welcome splash of color to our gardens, attracting pollinators and adding beauty to cut flower arrangements. Plus, they're tough enough to handle our variable weather, making them a rewarding choice for any Plains gardener.

We all know gardening on the Plains comes with its challenges: wind, drought, and those extreme temperature swings. But with a little planning and the right timing, you can absolutely grow beautiful Black-Eyed Susans. Our 188-day growing season gives you a good window to work with.

Starting Black-Eyed Susan seeds indoors isn't strictly necessary, but it can give you a head start, especially if you're aiming for blooms the first year. If you want to go this route, aim to start your seeds indoors from early to late February, about eight weeks before you plan to transplant them outside.

Use seed trays with a good seed-starting mix, keep them consistently moist (bottom watering helps prevent damping off), and provide plenty of light. A sunny windowsill might work, but a grow light is more reliable, especially with our variable spring weather. Keep the soil warm, around 70-75°F, for best germination.

Transplanting Black-Eyed Susans outdoors is best done from early April through early May. Before you move your seedlings outside, be sure to harden them off. This means gradually exposing them to outdoor conditions for about a week, increasing the time each day.

Plant them 12-18 inches apart in a sunny spot with well-drained soil. Keep an eye on the weather forecast; a late freeze or hailstorm can still happen in early spring. Buying starts from a local nursery is a good way to get blooms the first year, since they already have a head start.

Direct sowing Black-Eyed Susan seeds is a perfectly viable option, especially if you're not in a rush for first-year blooms. Sow seeds from mid April through late July.

Prepare the soil by loosening it and removing any weeds. Black-Eyed Susans prefer well-drained soil and need a soil temperature of at least 60°F for good germination. Sow seeds 12-18 inches apart and keep the soil consistently moist until they sprout. Direct sowing is easier, but you do run the risk of losing seedlings to pests or extreme weather.

Black-Eyed Susans are known for being drought-tolerant, which is a huge plus for us Plains gardeners. Once established, they need very little supplemental watering.

During the first few weeks after transplanting or when seedlings are young, water regularly to help them establish strong roots. After that, let the soil dry out between waterings. A good rule of thumb is to stick your finger about two inches into the soil; if it's dry, it's time to water. Usually, about 1 inch of water per week is plenty, but adjust based on rainfall. Remember, we often get periods of intense heat followed by dry spells here on the Plains.

Water at the base of the plant to avoid wetting the foliage, which can lead to fungal diseases, especially in our low-to-moderate humidity. Signs of underwatering include wilting leaves and stunted growth. Overwatering can cause root rot, so make sure your soil drains well. A layer of mulch can help conserve moisture and keep the soil cool during those hot summer months.

Deadheading Black-Eyed Susans is a simple way to encourage more blooms throughout the growing season. Simply snip off the spent flowers just below the flower head.

If you want to attract birds or allow the plants to self-seed, you can leave some of the seed heads on the plant. In late winter or early spring, before new growth emerges, cut back the entire plant to a few inches above the ground to encourage fresh growth.

You can expect your first Black-Eyed Susan blooms starting in late June and continuing through late October. The blooms are ready to harvest when the petals are fully open and the center cone is well-developed.

Cut the stems at an angle, leaving several inches of stem on the plant. Black-Eyed Susans make excellent cut flowers and will last for several days in a vase. To encourage continued production, keep deadheading spent flowers. As the first frost approaches (around mid- October), you can cut back the plants to encourage new growth next spring.

Even though Black-Eyed Susans are generally low-maintenance, they can still be susceptible to a few problems. Here are some common issues we see here on the Plains:

Powdery Mildew

• What it looks like: A white or grayish powdery coating on leaves, stems, and sometimes flower buds. Leaves may curl, yellow, and eventually die.
• What causes it: Fungi that thrive in warm days, cool nights, and moderate humidity. Surprisingly, dry leaf surfaces actually favor powdery mildew.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning to open up the canopy. Remove affected leaves promptly. Neem oil or potassium bicarbonate sprays can help control the spread. A milk spray (1 part milk to 9 parts water) is surprisingly effective. Plant resistant varieties if possible.

Septoria Leaf Spot

• What it looks like: Small, circular spots on the leaves, often with a dark brown or black border and a lighter center. Spots may merge together, causing the leaves to turn yellow and drop off.
• What causes it: A fungal disease that spreads through splashing water and infected plant debris. Warm, humid conditions favor its development.
• How to fix/prevent it: Remove and destroy infected leaves. Avoid overhead watering. Apply a fungicide containing chlorothalonil or copper if the problem is severe. Improve air circulation around plants. Clean up plant debris in the fall to reduce overwintering spores.

Aphids

• What it looks like: Clusters of tiny, soft-bodied insects (green, black, or white) on stems and leaf undersides. You might also see a sticky honeydew residue and curled or distorted new growth.
• What causes it: These sap-sucking insects reproduce rapidly, especially in warm weather. Ant colonies may "farm" them for honeydew.
• How to fix/prevent it: A strong spray of water from the hose can knock aphids off plants. Encourage natural predators like ladybugs and lacewings. Insecticidal soap is effective for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer, which attracts aphids.

Great Plains Specific Challenges: Our extreme temperature swings and variable rainfall can stress Black-Eyed Susans, making them more susceptible to diseases and pests. Wind protection is also essential, as strong winds can damage foliage and topple plants. Choosing drought-tolerant varieties and providing consistent watering during dry periods can help keep your plants healthy and thriving.

Black-Eyed Susans make great companions for several garden plants. They work well planted near tomatoes because they attract pollinators, which can improve fruit set.

Squash also benefits from the presence of Black-Eyed Susans, as the flowers draw in beneficial insects that help control squash vine borers. Many herbs, like rosemary and thyme, also make good companions, as their strong scents can deter pests. Avoid planting Black-Eyed Susans near plants that are highly susceptible to powdery mildew, as this can increase the risk of spreading the disease.