Black-Eyed Susan in Zone 3A — Great Plains

Black-Eyed Susans are a burst of sunshine in our Great Plains gardens, and they're surprisingly easy to grow. Their bright yellow petals bring cheer to any flower bed, plus they make excellent cut flowers for bringing a bit of the prairie indoors. You'll find they're a reliable source of color from midsummer well into fall.

Our region definitely throws some curveballs with extreme weather and variable rainfall, but Black-Eyed Susans are tough. With a little planning and attention to timing within our short 108-day growing season, you can enjoy these beauties year after year.

Starting Black-Eyed Susans indoors gives you a head start, especially if you're aiming for blooms the first year. It's doable, but honestly, these are so easy to direct sow or transplant, it's often not worth the extra effort unless you're after a specific variety.

If you choose to start indoors, sow seeds mid-March through early April, about eight weeks before you'd transplant outdoors. Use seed trays with good drainage, provide warmth (a heat mat helps), and make sure they get plenty of light – a grow light is ideal. Remember to water from the bottom to avoid damping off. Our springs here are known for temperature swings, so keeping them indoors a bit longer protects them from any late frosts.

Transplanting Black-Eyed Susans is a reliable way to get them established. Aim to transplant outdoors mid-May through mid-June, after the risk of frost has passed.

Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This toughens them up against our sometimes harsh Plains winds and intense sunshine. Space them 12-18 inches apart, giving them room to clump and spread. You can often find established Black-Eyed Susan starts at local nurseries. Buying starts will also give you blooms the first year.

Direct sowing Black-Eyed Susans is a simple, no-fuss method that works well. Sow seeds late May through mid-June, when the soil has warmed up.

Prepare the soil by loosening it and removing any weeds. Black-Eyed Susans aren't too picky, but they appreciate well-drained soil. Scatter the seeds lightly and gently press them into the soil. Keep the soil consistently moist until the seedlings emerge. Thin them to 12-18 inches apart once they're a few inches tall. Keep in mind that direct-sown plants may not flower as profusely in their first year.

Black-Eyed Susans are surprisingly drought-tolerant once established, making them perfect for our variable Great Plains rainfall. They're native prairie flowers, so they're built to withstand dry spells.

In the first few weeks after planting, water regularly to help them establish strong roots. After that, let the soil dry out between waterings. A good rule of thumb is to use the "finger test": stick your finger into the soil about two inches deep. If it feels dry, it's time to water. During the hottest parts of summer, they might need about an inch of water per week, either from rainfall or irrigation. Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our moderate humidity.

Watch for signs of underwatering, like wilting leaves. Overwatering can lead to root rot, so avoid soggy soil. A layer of mulch around the base of the plants helps retain moisture and suppress weeds, but be sure to leave some space around the stems to prevent rot.

Pruning Black-Eyed Susans is straightforward. Deadheading is the main task.

Throughout the blooming season, deadhead spent flowers to encourage more blooms. Simply snip off the flower heads below the spent bloom. If you want to let them self-seed or provide food for birds, leave some of the seed heads intact. In late winter or early spring, before new growth appears, cut back the entire plant to a few inches above the ground to make way for fresh growth.

Black-Eyed Susans bloom from midsummer into fall, providing a long season of cheerful color. Expect your first harvest of cut flowers from early August through mid-September, about 75 days after planting.

Harvest the flowers when they are fully open but before the petals start to fade. Cut the stems at an angle in the morning, when they're most hydrated. Removing flowers encourages the plant to produce more blooms.

As the first frost approaches in early September, you can either leave the remaining seed heads for the birds or cut back the plants for winter. Black-Eyed Susans self-seed readily, so be prepared for new plants popping up next year!

Even though Black-Eyed Susans are tough, they can occasionally run into problems. Here are a few common issues we see here on the Plains:

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes flower buds. Leaves curl, yellow, and die.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays can help. 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 that start as brown or reddish-brown and eventually turn gray with a dark border. The spots often merge, causing the leaves to yellow and drop off.
• What causes it: A fungal disease that spreads through splashing water and wind. It thrives in humid conditions and can be exacerbated by overcrowding.
• How to fix/prevent it: Remove and destroy infected leaves. Improve air circulation by spacing plants adequately. Water at the base of the plants to avoid wetting the foliage. Apply a fungicide containing copper or chlorothalonil if the infection 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: Rapid-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 knocks 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 and variable rainfall can stress Black-Eyed Susans, making them more susceptible to fungal diseases and aphid infestations. Wind can also be a factor, so providing some wind protection is helpful.

Black-Eyed Susans are good neighbors in the garden. They attract pollinators, which benefits other plants.

Good companions include tomatoes, which also thrive in full sun and benefit from the increased pollination. Squash is another good option, as the large leaves can help suppress weeds and retain moisture in the soil. Herbs like basil and oregano can also be planted nearby; their strong scents may help deter pests.

Avoid planting Black-Eyed Susans near plants that require consistently moist soil, as they prefer drier conditions. Too much water can lead to root rot.