Black-Eyed Susan in Zone 5B — Great Plains

Black-Eyed Susans bring a burst of sunshine to any garden, and they're especially rewarding here in Zone 5B. They're tough enough to handle our variable weather, plus they attract pollinators like crazy. Their bright blooms make excellent cut flowers, and they're just plain satisfying to grow in our prairie soil.

Our Plains climate can be a challenge, with its extreme temperature swings and occasional hail. But with a little planning around our 178-day growing season, you can successfully grow Black-Eyed Susans. Proper timing and understanding their needs are key.

Starting Black-Eyed Susans indoors isn't essential, but it can give you a head start, especially if you're aiming for blooms the first year. Start your seeds indoors from early February through early March, roughly 8 weeks before you plan to transplant them outside.

Use seed trays with a good seed-starting mix. Keep them warm and provide plenty of light – a grow light works wonders. Bottom watering helps prevent damping off. Keep in mind that spring in the Plains can be unpredictable, so having transplants ready gives you flexibility if the weather throws a curveball.

Transplant your Black-Eyed Susan seedlings outdoors from mid April through mid May, after the risk of hard frost has passed. Before you plant, harden them off by gradually exposing them to outdoor conditions for about a week.

Space them 12-18 inches apart to allow for their clumping growth habit. Be prepared for those late spring cold snaps that sometimes hit us here; row covers can be a lifesaver. Black-Eyed Susans are perennials, so buying starts will give you flowers the first year.

Direct sowing Black-Eyed Susan seeds is a simple and effective method. Sow directly into the garden from mid April through mid July. The earlier you sow, the more time they have to get established before winter.

Prepare the soil by loosening it and removing any weeds. Ensure the soil temperature is consistently above 60°F for best germination. Space the seeds 12-18 inches apart. While direct sowing is easy, keep in mind that the plants might not flower heavily in their first year.

Once established, Black-Eyed Susans are very drought-tolerant, making them perfect for our variable Plains climate. You won't need to water them constantly. Newly transplanted or direct-sown seedlings need regular watering until they get settled in.

During the hot summer months, check the soil moisture using the finger test – stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Typically, about 1 inch of water per week is sufficient, but adjust based on rainfall.

Water at the base of the plants to avoid wetting the foliage, especially with our low-to-moderate humidity, which can still encourage fungal diseases. Yellowing leaves can indicate overwatering, while wilting leaves signal underwatering. A layer of mulch helps retain moisture and regulate soil temperature during our extreme temperature swings.

Deadheading Black-Eyed Susans encourages a longer bloom period. Simply snip off the spent flowers just below the flower head throughout the growing season.

Alternatively, leave some seed heads on the plants in the fall. Birds love the seeds, and it allows for self-seeding, giving you more plants next year. In late winter, cut back the entire plant to a few inches above the ground to prepare for new growth in the spring.

You can expect your first Black-Eyed Susan blooms from early July through late October, about 75 days after planting. These flowers are excellent for cutting and bringing indoors.

Harvest the flowers when they are fully open and the petals are firm. Cut the stems at an angle, early in the morning for best results. Continuous harvesting encourages more blooms throughout the season.

As the first frost approaches around mid- October, you can still cut any remaining blooms. Or, leave the seed heads for winter interest and to provide food for birds. Black-Eyed Susans self-seed readily, so be prepared for new plants popping up next spring.

Here are some common problems you might encounter with Black-Eyed Susans in the Great Plains:

Powdery Mildew

• What it looks like: A white or grayish powdery coating on leaves, stems, and sometimes buds. Leaves may curl, yellow, and die.
• What causes it: Various fungi thriving in warm days, cool nights, and moderate humidity. Dry leaf surfaces can actually favor it. This is more common during our temperature swings.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning. Remove affected leaves promptly. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) can also be effective. Plant resistant varieties if available.

Septoria Leaf Spot

• What it looks like: Small, circular spots on leaves, often with a dark border and a lighter center. Spots may merge, causing leaves to yellow, brown, and drop off.
• What causes it: A fungal disease favored by wet conditions and overhead watering. Spores spread by splashing water.
• How to fix/prevent it: Remove and destroy infected leaves. Avoid overhead watering. Improve air circulation. Apply a fungicide containing copper or chlorothalonil if the problem is severe.

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapidly reproducing sap-sucking insects. Populations explode in warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: A strong water spray can knock them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap can be used for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer, as it attracts them.

Great Plains Specific Challenges: Our hot summers, low-to-moderate humidity, and variable rainfall can create conditions favorable for powdery mildew and aphid infestations. Drought can stress plants, making them more susceptible to problems. Be vigilant in monitoring your plants, especially during periods of extreme weather, and take preventative measures to ensure their health.

Black-Eyed Susans make excellent companions for several plants in a Great Plains garden. Plant them near tomatoes and squash. They attract beneficial insects like bees and butterflies, which help pollinate the vegetables.

Herbs like rosemary and thyme also benefit from being planted near Black-Eyed Susans. These herbs deter pests that might otherwise bother the Black-Eyed Susans. Avoid planting them near anything that prefers consistently moist soil, as Black-Eyed Susans thrive in drier conditions.