Understanding the appearance of a geranium involves two distinct groups of plants within the Geraniaceae family. The common name “geranium” is applied broadly to species across multiple genera, leading to diversity in form and color. These plants offer a wide range of visual characteristics, from foliage texture to the arrangement of their colorful blooms. Most recognizable features include deeply lobed leaves and flowers in shades of pink, red, purple, or white.
Understanding the Two Plant Groups
The common name “geranium” is most often used for two different genera: the true geraniums (Geranium) and the popular bedding plants (Pelargonium). This distinction is key to understanding their visual differences.
Geranium species are typically herbaceous perennials, often called “cranesbills” or “hardy geraniums.” They tolerate cold temperatures, have soft stems, and are generally lower-growing, often used as groundcover or border plants in temperate regions. Pelargonium species are generally tender perennials or subshrubs. They are grown as annuals in most climates, requiring winter protection. These plants, sometimes called “zonal geraniums” or “scented geraniums,” typically have a more bushy or upright growth habit. Geraniums are native to the Northern Hemisphere, while Pelargonium species largely originate from South Africa.
Distinctive Features of the Leaves and Stems
The foliage provides clear visual cues distinguishing the two groups. True Geranium leaves are generally broadly circular and palmately cleft, meaning lobes radiate from a central point, often with deep divisions. Leaf texture ranges from smooth to slightly hairy. Some varieties display attractive seasonal coloring, turning bronze or red in the fall.
The most common Pelargonium varieties, known as zonal geraniums, frequently exhibit a striking, horseshoe-shaped band of color on their leaves. This “zonal” marking is often a darker maroon or bronzy-green, contrasting with the rest of the leaf blade. Pelargonium stems are often sturdier and can become woody with age in larger, upright varieties. Many Pelargonium species, known as scented geraniums, are prized for the strong fragrances released when their leaves are crushed, mimicking scents like lemon, mint, or rose.
The Structure and Presentation of Geranium Flowers
The flowers offer the most reliable botanical difference between the two genera, centering on symmetry. True Geranium flowers possess radial symmetry, meaning they are star-shaped and can be divided into identical halves along multiple planes. These flowers typically have five petals of equal size and shape, often featuring delicate veining. They are borne singly or in loose clusters on thin, wiry stems, appearing in colors such as blue, pink, purple, or white.
Pelargonium flowers typically display irregular, or bilateral, symmetry. This often results in the five petals being differentiated, with the two upper petals appearing distinct from the three lower petals. Pelargonium flowers are generally grouped tightly together in dense, umbrella-like clusters called umbels. Their color palette is notably brighter, frequently including vibrant reds, oranges, and intense pinks, which are less common in true geraniums. After flowering, the true geranium develops a distinctive, elongated seed pod that looks like a bird’s beak, which is the source of the common name “cranesbill.” This structure springs open when ripe, catapulting its seeds away.