Petunias: How to Plant, Grow, and Care for Popular Annuals

Petunias are among the most popular flowers, often grown as annuals. They're tender perennials in Zones 9–11.

Two main groups:

1. Grandiflora petunias — very large flowers, best in containers/hanging baskets (more susceptible to rain damage).
2. Multiflora petunias — smaller but more abundant flowers, ideal for summer bedding/mixed borders (more tolerant of wet weather).

Planting Petunias

• Grow from seeds (start indoors 10–12 weeks before setting out) or easier: buy transplants. Seeds are tiny and need lots of light to germinate. Keep moist. Transplant when plants have three leaves.
• Best: buy transplants, plant in light, well-drained soil in full sun after last spring frost. Partial shade reduces flowers. Shelter from wind helps.
• Space ~1 foot apart.
• For containers, use soil-less mix.

Care

• Heat-tolerant—thorough weekly watering suffices (unless prolonged drought). Spreading types and containers need more frequent water.
• Fertilize monthly for good growth. Double-flowered cultivars like biweekly feeding.
• Deadhead faded flowers to prolong blooming.

Pests and Diseases

• Aphids
• Caterpillars
• Leaf miners
• Gray mold
• Bacterial soft rot
• Leaf spots
• Viruses

Recommended Varieties

• Carpet Series — ideal ground cover, wide color range.
• Sugar Daddy (Petunia Daddy Series) — purple flowers with dark veins.
• Rose Star (Petunia Ultra Series) — striped appearance from rose-pink flowers with white centers.