Calendula in Zone 7B — Southeast

Calendula is a fantastic addition to any Zone 7B garden here in the Southeast. The bright, cheerful flowers are beautiful, the petals are edible, and they attract pollinators. Plus, they're ridiculously easy to grow, providing a long season of color and even some medicinal benefits.

We know the Southeast can be tough on plants with our hot, humid summers and clay soil. But Calendula thrives with the right timing. Our long 235-day growing season gives you plenty of opportunity to enjoy these beauties.

Starting Calendula indoors isn't essential here in the Southeast, but it can give you a jump start on the season, especially if you want those first blooms as early as possible. If you're going this route, sow your seeds indoors from mid January through early February, about six weeks before you plan to transplant.

Use seed trays or small pots filled with a good seed-starting mix. Keep them warm and provide plenty of light, either from a sunny window or a grow light. Bottom watering is a great way to keep the soil consistently moist without overwatering, which can be a problem with our moderate spring humidity.

Transplant your Calendula seedlings outdoors from early March through mid April, once the danger of a hard frost has passed. Before planting them in the ground, harden them off by gradually exposing them to outdoor conditions for about a week.

Choose a spot with full sun to partial shade, and space the plants 8-12 inches apart. Even though it's spring, be mindful of late cold snaps that sometimes sweep through the Southeast. A frost blanket can be your best friend.

Direct sowing Calendula is the easiest way to grow it, and honestly, it works great here in the Southeast. You can direct sow from early March through mid September, giving you a long window of opportunity.

Simply prepare your soil by loosening it and removing any weeds, then sow the seeds directly into the ground, spacing them 8-12 inches apart. Keep the soil consistently moist until the seeds germinate. Direct sowing is great, but you will need to keep a close eye on the seedlings to protect them from pests.

Calendula prefers moderate watering, which can be a bit of a balancing act in our humid Southeast climate. While somewhat drought-tolerant, they'll perform best with consistent moisture, especially during the cooler parts of the growing season. But overwatering can lead to fungal issues.

During the spring and fall, when temperatures are milder, aim to water about 1 inch per week if rainfall is lacking. Use the finger test – if the top 2 inches of soil feel dry, it's time to water. During the heat of the summer, Calendula might go dormant, so reduce watering slightly. Try to water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid environment.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. A good layer of mulch, like pine straw or shredded hardwood, helps retain moisture and suppress weeds.

Deadheading is key to keeping your Calendula plants blooming throughout the season in the Southeast. Regularly remove spent flowers to encourage the plant to produce more blooms.

Simply snip off the flower heads just below the bloom, leaving the healthy foliage intact. You can deadhead throughout the growing season, from spring through fall. If you leave some flowers to mature, the plant will self-seed, giving you even more Calendula next year. As the first frost approaches around early November, stop deadheading to allow the plant to set seed if you want to collect them or let them self-sow.

You can expect your first Calendula harvest about 45 days after planting, so from mid April through mid November here in the Southeast. Harvest the flowers when they are fully open, ideally in the morning after the dew has dried.

Gently snip the flower heads from the plant, being careful not to damage the surrounding foliage. Regular harvesting encourages continued production, so don't be shy about picking those blooms! As the first frost approaches in early November, harvest all remaining open flowers. You can dry them for later use or enjoy them fresh.

Here are a few common problems you might encounter with Calendula in the Southeast:

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems. Leaves may curl, yellow, and die.
• What causes it: Fungi that thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it. Our Southeast humidity is often a factor.
• How to fix/prevent it: Improve air circulation through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays can help. Milk spray (1 part milk to 9 parts water) is surprisingly effective.

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: Strong water spray knocks them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap for heavy infestations. Neem oil works systemically.

Whiteflies

• What it looks like: Tiny white, moth-like insects that fly up when disturbed. Yellowing or stippled leaves. Sticky honeydew.
• What causes it: Sap-sucking insects that thrive in warm, humid conditions. Our long, hot summers in the Southeast provide ideal conditions for them.
• How to fix/prevent it: Yellow sticky traps can capture adults. Strong water spray dislodges them. Insecticidal soap or neem oil. Reflective mulch can deter them.

Southeast Specific Challenges: The hot, humid summers and wet-summer rainfall of the Southeast create a perfect environment for fungal diseases like powdery mildew. Good air circulation is crucial. Also, be vigilant about pests like aphids and whiteflies, as their populations can explode quickly in our warm climate.

Calendula makes a great companion plant for many vegetables in the Southeast garden. Plant them near tomatoes and peppers to attract pollinators, which will improve fruit set. They also help deter certain pests that bother these crops.

Green beans also benefit from Calendula as a companion. The Calendula attracts beneficial insects that prey on bean pests. Avoid planting Calendula near cabbage family plants, as they can attract cabbage white butterflies, whose larvae will happily munch on your brassicas.