Echinacea in Zone 8B — Desert Southwest

Echinacea, also known as coneflower, is a fantastic addition to your Desert Southwest garden. Its vibrant blooms add beauty, attract pollinators, and its drought tolerance means it can handle our arid climate better than many other ornamentals. Plus, you can harvest the petals for tea – a soothing treat after a long day working in the sun.

Desert gardening comes with its challenges: extreme heat and alkaline soil, to name a few. But with careful timing and a little extra attention, you can successfully grow Echinacea here. Our long 279-day growing season gives you two opportunities to get these beauties established.

Starting Echinacea indoors is an option, but honestly, with our mild winters and long growing season, it's often not necessary. If you want a head start, though, begin in late December through mid January, about eight weeks before you plan to transplant. Use seed trays with a good seed-starting mix, provide warmth (a heat mat helps), and ensure they get plenty of light – a grow light is ideal.

Remember to water from the bottom to avoid damping off. Place the tray in a shallow container of water until the soil surface is moist. Given our very-early spring character, getting a jump start indoors can give you an edge, but don't feel pressured.

Transplant your Echinacea seedlings outdoors in late February through mid March. Harden them off for about a week beforehand by gradually exposing them to outdoor conditions. This helps them adjust to the intense Desert Southwest sun and temperature swings.

Space them 18-24 inches apart in well-draining soil. Keep an eye on the weather forecast – late frosts can still happen, so be ready to cover your young plants if needed. Echinacea is a perennial, so consider buying starts for easier results, as the seeds need cold stratification.

Direct sowing Echinacea is perfectly doable in the Desert Southwest. Sow seeds from late February through mid August. Prepare the soil by loosening it and mixing in some compost.

Make sure the soil temperature is consistently above 60°F for good germination. Plant seeds 18-24 inches apart and keep the soil consistently moist until they sprout. Direct sowing can be less work, but remember that the plants will take longer to mature compared to transplants.

Echinacea is wonderfully drought-tolerant once established, which is a huge plus for Desert Southwest gardens where water is precious. This native plant thrives in the type of poor, dry soil we often have, so don't pamper it. Remember, our summer heat is extreme, with typical highs around 105°F, and the humidity is arid.

In spring and fall, water deeply about once a week, providing about 1 inch of water. During the monsoon season, let the rains do the work. In the extreme heat of summer, you might need to increase watering to twice a week if the plants show signs of stress.

Always use the finger test: stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Water at the base of the plant to avoid fungal diseases, especially during our humid monsoon season. A layer of rock mulch helps retain moisture and regulate soil temperature, crucial in our climate. Yellowing leaves indicate overwatering, while drooping leaves suggest underwatering.

Pruning Echinacea is simple. Deadhead spent flowers throughout the growing season (late May through early December) to encourage more blooms. Just snip off the flower heads below the first set of leaves.

Alternatively, leave some seed heads on the plants. The goldfinches love them, and they add winter interest to your garden. In late winter, after the first frost (around early December in the Desert Southwest), 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 Echinacea harvest in late May through early December, about 90 days after planting. The flowers will be in full bloom midsummer to fall. A great sign of ripeness is when the petals are fully open and the central cone is prominent.

To harvest, simply cut the flower stems near the base of the plant. Leave some seed heads on the plants for the goldfinches – they’ll appreciate it. You can harvest the petals for tea; dry them thoroughly before storing.

Keep harvesting regularly to encourage continued production. As the first frost approaches in early December, harvest any remaining flowers. You can dry them indoors.

Here are a few common problems you might encounter with Echinacea in the Desert Southwest:

Aster Yellows

• What it looks like: Distorted, greenish flowers, stunted growth, and yellowing leaves.
• What causes it: A phytoplasma (bacteria-like organism) transmitted by leafhoppers. It's more prevalent during periods of high leafhopper activity, often coinciding with our monsoon season.
• How to fix/prevent it: Unfortunately, there's no cure. Remove and destroy infected plants immediately to prevent spread. Control leafhopper populations with insecticidal soap or neem oil.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes flower heads. Leaves curl, yellow, and die. Reduces plant vigor.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it. Our monsoon season, with its humidity spikes, can create favorable conditions.
• 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. Plant resistant varieties.

Japanese Beetles

• What it looks like: Metallic green beetles that skeletonize leaves, leaving a lacy appearance.
• What causes it: These beetles are attracted to various plants, including Echinacea. They can be particularly problematic during the warmer months.
• How to fix/prevent it: Handpick beetles and drop them into soapy water. Use row covers to protect plants. Neem oil can also deter them.

Desert Southwest Specific Challenges: Our extreme heat can stress Echinacea, making it more susceptible to pests and diseases. The arid humidity can sometimes reduce the risk of fungal issues, but the monsoon rainfall can create spikes in humidity that favor powdery mildew. Alkaline soil may also affect growth, so amend with compost to improve drainage and nutrient availability.

Echinacea benefits from companion planting in the Desert Southwest. Tomatoes and peppers make good neighbors because they enjoy similar sun and watering conditions. Plus, the taller tomato plants can provide some afternoon shade to protect the Echinacea from sunscald during our hottest months.

Herbs like rosemary and lavender are also excellent companions. They attract beneficial insects that help control pests and don't compete for water. Avoid planting Echinacea near anything that requires consistently moist soil, as it prefers drier conditions.