Zonal Geranium: A Gardener’s Guide

Zonal geraniums belong to the Pelargonium genus, distinct from true geraniums. Native to South Africa, they thrive in warm climates. Their name, zonal, comes from the noticeable dark band on their leaves.

Characteristics

Zonal geraniums are popular for their vibrant flowers and ease of care. They exhibit scalloped, heart-shaped leaves with marked zones, often darker in the center. Flowers bloom in clusters, showcasing hues of red, pink, white, salmon, and bi-colors. Sensible gardeners appreciate their striking blooms and prolonged flowering periods.

Planting Zonal Geraniums

Successful planting begins with choosing healthy plants. Select those with vigorous growth and no yellow leaves. The soil should be well-draining, preferably a mix of potting soil and perlite. Ideal pH levels range from 6.0 to 6.5.

• Location: Position in full sun for optimal flowering. A minimum of six hours of sunlight is essential.
• Watering: Water when the top inch of soil feels dry. Ensure no waterlogging to prevent root rot.
• Temperature: Maintain temperature between 18°C to 24°C (65°F to 75°F).

Propagation

Propagation of zonal geraniums can be accomplished via seeds or cuttings. Cuttings are typically more straightforward and faster.

From Seeds

• Sow seeds indoors 10-12 weeks before the last frost date.
• Use seed-starting mix, covering seeds lightly.
• Maintain consistent moisture and a temperature of 21°C (70°F).
• Transplant seedlings outdoors after the danger of frost has passed.

From Cuttings

• Select a healthy stem, 4-6 inches long, cutting just below a node.
• Remove the lower leaves and any flowers or buds.
• Dip the cut end in rooting hormone.
• Plant in a moist, sterile potting mix and place in bright, indirect light.

Care and Maintenance

Zonal geraniums demand regular deadheading to promote continuous blooming. This involves removing spent flowers and damaged leaves. Regular fertilization enhances growth and flowering.

• Fertilization: Use a balanced, water-soluble fertilizer every 3-4 weeks during the growing season.
• Pruning: Prune leggy growth in early spring to encourage bushier plants.

Common Pests and Problems

Zonal geraniums can encounter issues like pests and diseases. Common pests include aphids, spider mites, and whiteflies.

• Aphids: Small, green insects gathering on new growth. Use insecticidal soap or neem oil.
• Spider Mites: Tiny red or brown spiders causing webbing. Increase humidity and use insecticidal soap.
• Whiteflies: Small white insects flying when disturbed. Use yellow sticky traps to manage infestations.

Common disease issues include bacterial blight and powdery mildew.

• Bacterial Blight: Yellowed leaves with black spots. Remove infected parts and improve air circulation.
• Powdery Mildew: White, powdery coating on leaves. Treat with fungicide and ensure good air flow.

Benefits of Growing Zonal Geraniums

These plants are not only beautiful but beneficial. They act as natural insect repellents, deterring mosquitoes and other bugs. Their essential oils have potential therapeutic uses, alleviating stress and inflammation.

Overwintering

Zonal geraniums are tender perennials. In colder climates, they must be brought indoors before the first frost. Potted plants can be moved indoors, while garden plants can be uprooted, trimmed, and stored in a cool, dark place.

• Method 1: Bring pots indoors to a sunny spot. Reduce watering and stop fertilizing.
• Method 2: Dig up garden plants, shake off soil, and hang them upside-down in a cool, dark place. Replant in spring.