Coleus is a stunning ornamental plant cherished globally for its vibrant, highly patterned foliage, offering a spectrum of colors that rival any flower. A precise count of varieties is impossible due to the continuous development of new hybrids and complex shifts in its botanical classification. The vast majority of the “varieties” available to gardeners are not naturally occurring species but are the result of intense human cultivation and breeding efforts.
The Scientific Naming Challenge
The confusion surrounding the number of Coleus varieties begins with its formal scientific name, which has been in constant flux for decades. Historically, the plant was known as Coleus blumei and later Coleus scutellarioides. Taxonomists eventually merged the genus Coleus into Plectranthus based on morphological characters, such as the structure of the flower’s stamens.
Recent phylogenetic analysis, which uses DNA sequencing to map evolutionary relationships, found that the genus Plectranthus was not a single, distinct group (paraphyletic). This research led to a significant re-evaluation and the formal resurrection of the genus Coleus in 2019. The number of recognized true species within the re-established Coleus genus is now around 300, including species transferred from Plectranthus and other related genera.
The distinction between a true species and a cultivated variety is fundamental to the count. A species is a naturally occurring population that can reproduce freely, while a “variety” in the horticultural sense refers to a cultivar. This ongoing taxonomic debate illustrates that the scientific understanding of the plant is still evolving. The vast array of plants available to consumers are domesticated selections created by breeders, not wild species.
The Explosion of Cultivars and Hybrids
The seemingly endless number of Coleus types is due to intentional breeding and hybridization, resulting in thousands of cultivated varieties, or cultivars. A cultivar is a plant selected and propagated by humans for desirable traits. Coleus hybrids were first introduced in England around 1862, quickly becoming popular and sparking a breeding race to develop new colors and forms.
Modern breeding programs continue to generate tens of thousands of seedlings annually to find the next unique cultivar. For example, a single program might grow 50,000 to 70,000 seedlings in a season, with only a tiny fraction selected for further evaluation. The goal of these programs is to create new plants with improved vigor, better branching, and vibrant, non-fading colors that perform well in diverse environments.
Once a unique plant is selected, it is propagated vegetatively (from cuttings) to ensure every new plant is genetically identical to the parent. These distinct, named plants are registered and released to the market, often designated by single quotation marks, such as ‘Black Dragon’ or ‘Wasabi’. With well over a thousand named cultivars currently in circulation, the actual number of distinct, named varieties is far more than the number of species.
Grouping Varieties by Physical Characteristics
Since an exact total number of varieties is unattainable, growers and gardeners categorize the extensive diversity of Coleus based on distinct physical characteristics, known as the plant’s phenotype. One primary grouping is by the plant’s growth habit, which determines how it is best used in a landscape. Cultivars are broadly divided into upright or bushy types, and trailing types, which are ideal for hanging baskets and window boxes.
Leaf characteristics provide a second major point of classification, encompassing size and shape. Some varieties, like the ‘Kong’ series, feature extra-large leaves, while others are miniature. Shapes can be highly varied, including the classic ovate or lanceolate, as well as specialized forms like the deeply lobed or cut-leaf types, sometimes called “duckfoot” or “fringed”. The texture can also range from smooth to highly ruffled or jagged.
The most celebrated characteristic is the color pattern, which is how most varieties are marketed. Colors can range from nearly black and deep burgundy to bright chartreuse, yellow, pink, and red, often appearing in complex combinations. These patterns include solid colors, intricate mosaics of several shades, and precise veining. Light exposure often influences the intensity and depth of these colors, with sun-tolerant varieties displaying more dramatic pigmentation.