Flower of Geranium Plant - Geraniaceae Pelargonium.

What You Need to Know About the Geranium Plant – Geraniaceae Pelargonium

Better known as geraniums, the pelargoniums tend to be the varieties of the family grown for indoors. Being closely related to their outdoor counterparts, they bear a strong resemblance, but have pointed rather than rounded leaf lobes. Pelargonium is a large group, covering plants grown for their bright flowers and others for their scented foliage. They are bushy subshrubs with rounded or divided leaves and a long flowering season.

Most originate from South Africa, with a few from tropical Africa, Australia, and the Middle East. P. crispum, also called lemon geranium, is a scented-leaf pelargo­nium, grown for its aromatic foliage rather than its small pink flowers. The stems are stiffly upright, but reg­ular pinching can be used to control the shape of the plant.

Its rough-tex­tured leaves are Vo in. (1.5 cm) across, rounded, and strongly lemon scented. Varieties include: P.c. ‘Major’ which has larger leaves; P.c. ‘Minor’ with small, crisped leaves, and P.c. ‘Peach Cream’ with pink flowers and smelling of peaches. Height up to 2 ft. (60 cm) if left unchecked.

Regal geraniums (P. x domesticum hybrids) are a large group of hybrids of complicated origins. All have thick, branching stems and hairy, toothed leaves up to 4 in. (10 cm) across. The flowers are large and showy, and are borne in upright clusters, in single or combined shades of white, pink, salmon, orange, red, or purple; the upper petals are often blotched with a darker color. They are usually single. P. ‘Carisbrooke’ has large, pink flow­ers. marked wine-red.

P.’Pompeii’ is a compact plant bearing flowers with nearly black petals and narrow pink- white edges. Height 18 in. (45 cm). Ivy-leafed geraniums (P. peltatum) are a trailing or climbing variety of evergreen pelargonium with fleshy, bright green leaves with a darker cen­tral zone. The flowers are single to double, with colors including white, pink, red, mauve, and purple, often with darker veins.

They are excellent plants for hanging baskets. Zonal geraniums (P. x hortorum.) are hybrids with smooth, succulent stems and large, rounded leaves, up to 4 in. (10 cm) in diameter, sometimes variegated or marked with a darker horse- shoe-shaped zone. The flowers may be single, semi double, or double, in shades of white, orange, pink, red, purple, and occasionally yellow. Height 2 ft. (60 cm). The group can be divided into various new and traditional categories:

Cactus-flowered: single or double flowers with narrow, twisted petals. Single-flowered: flowers with five petals or less.

Double- and semi double-flowered: flowers with six or more open petals. Stellar: small plants with irregularly star-shaped flowers, and often zoned leaves.

Rosebuds: flowers with many small petals packed tightly in the center. Fancy-leaved: grown for foliage which may be gold, silver, green, white, black, or bronze in combination.

Irenes: fast-growing, free-flowering, with large flower heads.

Miniatures and dwarfs: compact and free-flowering; miniatures reach 5 in. (15 cm) and dwarfs up to 8 in. (20 cm) in height.

Many zonal geraniums will not breed true from seed and must be propagated by taking cuttings; usually these are the more showy varieties, ideal for the house or conservatory.

Size: See individual groups or species.

Light: Direct or indirect sunlight.

Temperature: Normal room.

Moisture: Keep moist from spring to­ fall. In winter, apply enough water to prevent sod drying out.

Feeding: Give half-strength liquid fertilizer once a month in spring and summer

Propagation: Take tip or stem cut­tings in spring or summer; remove small stipules and leaves from the nodes on the lower third of the stem. Allow cuttings to wilt for 30 minutes before inserting into soil mix or water for rooting.

Special needs: Do not use rooting hormone when taking cuttings of any pelargonium, as they naturally contain high levels of hormone, so adding extra will make the stem rot.