Pelargonium x hybridum

Zonal pelargonium is a low-maintenance, tender perennial grown as an annual or a houseplant. It is in the geranium family (Geraniaceae). It is a hybrid cross between Pelargonium zonale and Pelargonium inquinans, both of which are native to the Cape region of South Africa.

Zonal pelargonium requires full sun and soils that are well-drained. Once established, plants are drought-tolerant, but they grow and flower more luxuriantly with moderate moisture. Plants in containers may be allowed to dry out between waterings. In insufficient light, plants become leggy and bloom poorly. Seeds should be started indoors in January or February on top of a heat mat set to 70 to 75 degrees. Plant outside after the last frost. Stem cuttings may be taken from July to August and grown under glass or in a sunny window until the danger of frost has passed. Plants can be overwintered indoors or in a cool greenhouse. Indoors, if they have adequate light, the plants can be kept growing with regular watering. Otherwise, they should be kept very dry and allowed to go dormant. Water the plants sparingly, only when the plants show signs of wilting. After the danger of frost has passed, the plants can be brought out of dormancy and watered normally. Give excellent ventilation to prevent foliar diseases.

The humble zonal pelargonium is a marvel of modern breeding. The hybrid was first made in the late 18th century, but modern hybrids are uniform, floriferous and disease-resistant. The plant forms a rounded mound 1 to 3 feet tall. Flowers of pelargonium may be single, semi-double or double and are most commonly red, pink or white. The plant blooms throughout the warm months until frost. Horticulturists recognize several groups of zonal pelargoniums, including:

• Stellar cultivars, which have leaves with pointed lobes, include ‘Stellar Arctic Star’ and ‘Stellar Snowflake’.
• Cactus- or Poinsettia-flowered, which have twisted or quilled petals, including ‘Tangerine’, ‘Spitfire’ and ‘Coronia’.
• Rosebud cultivars, which have such tight clusters of flowers that the flowers never completely open, including ‘Appleblossom Rosebud’, ‘Wedding Royale’, and ‘Rosebud Supreme’.
• Miniatures, which are no more than 8 inches tall, include ‘Anna’, ‘Delta’ and  ‘Jane Eyre’.

Pelargonium is a popular plant for hanging baskets, containers and garden beds. It can be overwintered indoors as a houseplant in a bright location.

Quick ID Hints:

• Flowers in umbel-like clusters on an elongated peduncle
• Leaves reniform to orbicular, often with a dark band within the margin (the “zone” of zonal pelargoniums)

Insects, Diseases, and Other Plant Problems: Susceptible to caterpillars, spider mites, mealybugs, fungal diseases and bacterial diseases. 

VIDEO Created by Elisabeth Meyer for "Annuals, Perennials, Vines, and Groundcovers," a plant identification course developed in partnership with Longwood Gardens. Note: Throughout the video, the presenter refers to the plant as Pelargonium x hortorum. This name is now a synonym of P. x hybridum. Also, the presenter calls the inflorescence an umbel. While the inflorescence is umbel-like, it is not a true umbel. 

More information on Pelargonium.