Black-Eyed Susan in Zone 7B — Desert Southwest

Black-Eyed Susans bring a cheerful burst of color to our Desert Southwest gardens, and they're surprisingly well-suited to our climate. Plus, they attract pollinators like nobody's business! These beauties can handle our heat and add a touch of that wildflower look to your yard.

Desert gardening definitely has its quirks, from the extreme heat to our alkaline soil. But with a little planning and smart timing during our long 245-day growing season, you can absolutely grow Black-Eyed Susans successfully here.

Starting Black-Eyed Susans indoors here in the Desert Southwest isn't essential, but it can give you a head start, especially if you want blooms the first year. Start your seeds indoors in early to late January, about eight weeks before you plan to transplant.

Use seed trays with a good seed-starting mix and keep them warm – around 70-75°F. Bottom watering helps prevent damping off and keeps the seedlings evenly moist. Place them under grow lights because even our sunny windowsills might not provide enough consistent light. Remember, our spring comes very early, so getting a jump start indoors is a good move.

Transplant your Black-Eyed Susan seedlings outdoors in early March through early April. Before you move them permanently, harden them off by gradually exposing them to outdoor conditions for about a week. This is crucial to prevent shock.

Space the plants about 12-18 inches apart to allow for good air circulation. Even though March and April are generally mild, keep an eye on the forecast for any late cold snaps. Since Black-Eyed Susans are perennials, consider buying starts if you want flowers in that first year.

Direct sowing Black-Eyed Susan seeds is a viable option, especially if you're going for a more naturalized look. Sow seeds from mid-March through mid-August.

Prepare the soil by loosening it and removing any rocks or debris. Black-Eyed Susans aren't too picky, but they prefer well-draining soil. Keep the soil consistently moist until the seedlings emerge. Thin the seedlings to 12-18 inches apart once they're a few inches tall. Direct sowing is easy, but you might not get blooms the first year.

Black-Eyed Susans are surprisingly drought-tolerant once established, making them a great choice for desert gardening. During the hottest parts of summer, though, they'll still need supplemental watering.

A good rule of thumb is to water deeply about once a week, giving them about an inch of water. Use the "finger test" – stick your finger about two inches into the soil. If it feels dry, it's time to water. During our monsoon season, you might not need to water at all! Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our arid environment.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to root rot, so make sure the soil drains well. Applying a layer of mulch around the base of the plants helps retain moisture and keeps the soil cooler.

Deadheading Black-Eyed Susans is key to keeping them blooming longer. Simply snip off the spent flowers just below the flower head. This encourages the plant to produce more blooms instead of focusing on seed production.

You can deadhead throughout the growing season, from late spring through fall. In late winter, after the first frost (around mid- November), cut the plants back to a few inches above the ground. This helps tidy them up and encourages new growth in the spring. Alternatively, leave some seed heads for the birds and for self-seeding, if you want more plants next year.

You can expect your first Black-Eyed Susan blooms about 75 days after planting, which means a harvest from late May through late November. These flowers make excellent cut flowers, so don't hesitate to bring them indoors.

Harvest the flowers when they are fully open and the petals are vibrant. Cut the stems at an angle, and remove any leaves that will be below the waterline in your vase. To encourage continuous blooming, keep harvesting the flowers regularly.

As the first frost approaches in mid- November, you can still harvest any remaining blooms. After the frost, cut back the plants as described in the pruning section.

Here are a few common problems you might encounter with Black-Eyed Susans in our Desert Southwest gardens:

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes buds. Leaves might curl, yellow, and eventually die.
• What causes it: Powdery mildew thrives in warm days, cool nights, and moderate humidity. Surprisingly, dry leaf surfaces actually favor it.
• How to fix/prevent it: Improve air circulation by spacing plants properly 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 surprisingly effective.

Septoria Leaf Spot

• What it looks like: Small, circular spots on the leaves that start as yellow and turn brown or black. Spots may have a light center. Severely affected leaves will yellow, wither, and drop.
• What causes it: A fungal disease favored by wet conditions and overhead watering. Spores spread by splashing water and wind.
• How to fix/prevent it: Remove and destroy infected leaves. Avoid overhead watering. Improve air circulation. Apply a fungicide 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 might be present, and new growth might be curled or distorted.
• What causes it: These sap-sucking insects reproduce rapidly, especially in warm weather. Ant colonies often "farm" them for their honeydew.
• How to fix/prevent it: Knock them off with a strong spray of water. Encourage ladybugs and lacewings, which are natural predators. Use insecticidal soap for heavy infestations. Neem oil also works well.

Desert Southwest Specific Challenges: Our extreme heat can stress Black-Eyed Susans, making them more susceptible to pests and diseases. Ensure adequate watering and provide afternoon shade if needed. Our monsoon season's humidity can also exacerbate fungal problems like powdery mildew and septoria leaf spot, so good air circulation is key.

Black-Eyed Susans make great companions for several plants in our Desert Southwest gardens. Tomatoes benefit from the shade Black-Eyed Susans provide, which helps prevent sunscald. Squash enjoys the pollinator-attracting power of these flowers, leading to better fruit set.

Many herbs, like rosemary and lavender, also make good companions because they attract beneficial insects that can help control pests. Avoid planting Black-Eyed Susans near plants that are susceptible to the same diseases, like powdery mildew, to prevent the spread of infection.