Petunia Petunia x hybrida

Garden petunia is a tender perennial in the nightshade family (Solanaceae). Its hardiness zones range from 10a to 11b, which results in it being an annual in North Carolina gardens. Petunia’s genus name is derived from the Brazilian name for tobacco.   

Seeds can be sown in January to March under glass as they require a germination temperature of 72 to 75 degrees F, but many people purchase plants or plugs from local nurseries. Pinching purchased plants back before transplanting them will help them maintain a bushy habit. Plant in full sun to partial shade and in light and well-drained soils. While it can survive in heavy shade, the blooms will suffer. Deadheading provides optimal performance and increased flower bud production. Leggy plants should be pinched back. Plants may be overwintered indoors in a bright location away from heated air. This plant has moderate drought tolerance. It can tolerate poor soils as long as they have good drainage. Depending on the hybrid, petunias require 1 to 3 feet of space in the garden.

This low to medium maintenance plant comes with a wide range of flower colors including variegated. Petunias bloom continuously throughout the summer until frost and is one of the most popular bedding plants. Hundreds of cultivars have been developed. The major groupings of hybrid petunias are:

• Cascading hybrids: Cascading stems best for hanging baskets or ground covers.

• Grandiflora hybrids: Large showy flowers up to 4 inches wide.

• Multiflora hybrids: Smaller flowers 2 inches wide but more abundant than Grandiflora.

• Milliflora hybrids: The newest group are miniature plants with small but abundant blooms. 

Plant in mass in beds and border fronts; along the edges of patios and hardscapes; in containers, hanging baskets or window boxes; or in interior sunrooms in the winter, depending on the hybrid. Include them also in butterfly and pollinator gardens as the flowers attract butterflies, hummingbirds and other pollinators. This plant is seldom damaged by deer. 

Quick ID Hints:

• Funnelform flowers.

• Anthers yellow.

• Decumbent herb with sticky pubescence.

Insects, Diseases and Other Plant Problems:  Aphids, flea beetles, slugs and snails are insect problems. Root rot, gray mold and tobacco mosaic virus are disease problems. Some cultivars have shown poor resistance to phytophthora root rot or stem rot. See Phytophthora Root and Crown Rot in the Landscape.

VIDEO Created by Elisabeth Meyer for "Annuals, Perennials, Vines, and Groundcovers" a plant identification course offered in partnership with Longwood Gardens.