Black-Eyed Susan in Zone 8A — Pacific Northwest

Black-Eyed Susans are a cheerful addition to any Pacific Northwest garden, bringing a burst of sunny color that lasts from midsummer well into our long, mild fall. Their daisy-like blooms are fantastic as cut flowers, and the seed heads provide winter interest while feeding the birds. Plus, they're incredibly low-maintenance once established, making them perfect for our busy gardening schedules.

While our cool springs and potential for late blight can present challenges, Black-Eyed Susans are well-suited to our 203-day growing season. You can get a head start indoors or direct sow with success. With a little attention to watering and spacing, you'll be rewarded with a vibrant display.

Starting Black-Eyed Susans indoors is an option, especially if you want blooms the first year. Starting seeds indoors from late January through mid February gives you a jump on the season, about eight weeks before you can transplant them outdoors. This is useful if you want to ensure flowering the first year.

Use seed trays with a good seed-starting mix, and provide consistent bottom watering to keep the soil evenly moist without overwatering. Place the trays in a warm location with plenty of light – a sunny windowsill or under grow lights works well. With our overcast spring days, grow lights are often beneficial.

Transplant your Black-Eyed Susan seedlings outdoors from early April through early May, once the soil has warmed up a bit. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the cooler temperatures and stronger sunlight.

Choose a sunny spot with well-drained soil, spacing the plants 12-18 inches apart to allow for good air circulation. Keep an eye on the weather forecast, as we can still experience cool snaps and even late frosts during this period. These are perennial plants, but you'll often find starts at local nurseries that will flower the first year.

Direct sowing Black-Eyed Susan seeds is a straightforward method, especially since our mild summers give them plenty of time to establish. Sow seeds outdoors from early April through early August, when the soil temperature is consistently above 60°F. Prepare the soil by loosening it and removing any weeds.

Sprinkle the seeds lightly over the soil surface and gently press them in, but don't bury them too deeply. Keep the soil consistently moist until the seedlings emerge, which usually takes about two weeks. Thin the seedlings to 12-18 inches apart once they're a few inches tall. Direct sowing is reliable, but you may not get flowers the first year.

Black-Eyed Susans are very drought-tolerant once established, making them ideal for our dry summer months. During the spring, when the plants are young or newly transplanted, water them regularly to keep the soil consistently moist. Use the finger test: if the top two inches of soil feel dry, it's time to water.

Once established, reduce watering to about one inch per week, only when rainfall is scarce. Water at the base of the plant to avoid wetting the foliage, which can help prevent fungal diseases in our sometimes humid conditions. Overwatering can lead to root rot, so allow the soil to dry out slightly between waterings.

Signs of underwatering include wilting leaves and stunted growth, while overwatering can cause yellowing leaves and a mushy stem base. Applying a layer of mulch around the base of the plants helps retain moisture and suppress weeds, which is especially helpful during our drier months.

Deadheading Black-Eyed Susans is key to encouraging continuous blooms throughout the summer and into fall. Simply snip off the spent flowers just below the flower head, being careful not to damage any new buds. Do this regularly to keep the plants looking tidy and to promote more flowers.

Alternatively, you can leave some of the seed heads intact to provide food for birds during the winter months and to allow the plants to self-seed. 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 and a bushier habit.

You can expect your first Black-Eyed Susan blooms starting in late June and continuing through early November, provided we don't have an unusually early frost. The flowers are ready to harvest when they are fully open and the petals are firm. Cut the stems at an angle, leaving several inches of stem on the plant to encourage new growth.

Harvesting the flowers regularly encourages the plant to produce more blooms throughout the season. To prolong the vase life of cut flowers, remove any leaves that will be below the waterline. As the end of the season approaches in late October, you can still harvest any remaining blooms, or leave them for winter interest and birdseed.

Black-Eyed Susans are generally trouble-free, but here are a few common problems to watch out for in the Pacific Northwest:

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems. Leaves curl, yellow, and die.
• What causes it: 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 through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays help. Milk spray (1 part milk to 9 parts water) is surprisingly effective.

Septoria Leaf Spot

• What it looks like: Small, circular spots on the leaves that are initially brown or black, then develop gray centers. The spots may merge, causing the leaves to yellow and drop off.
• What causes it: A fungal disease that spreads through splashing water and infected plant debris. Our wet springs and mild, humid summers can create favorable conditions for its development.
• How to fix/prevent it: Remove and destroy infected leaves and plant debris to prevent the fungus from spreading. Improve air circulation around the plants. 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.
• How to fix/prevent it: Strong water spray knocks them off. Encourage ladybugs and lacewings. Insecticidal soap for heavy infestations.

Pacific Northwest Specific Challenges: Our mild heat and dry-summer rainfall means Black-Eyed Susans are less susceptible to some diseases compared to other regions. However, our cool, wet springs can still create conditions favorable for fungal issues like septoria leaf spot, so good air circulation and prompt removal of infected foliage are important.

Black-Eyed Susans make great companions for several plants in your Pacific Northwest garden. Tomatoes benefit from the shade provided by Black-Eyed Susans during our mild summer heat, and the flowers attract pollinators that also help with tomato production. Squash also appreciates the partial shade and the pollinators.

Herbs like rosemary and thyme are good companions because their strong scents can help deter pests that might otherwise bother the Black-Eyed Susans. Avoid planting Black-Eyed Susans near plants that are highly susceptible to powdery mildew, as this can increase the risk of the disease spreading.