Hostas are among the most popular shade-loving perennials, celebrated for their lush foliage that transforms dark garden spaces. The diversity within the genus Hosta is vast, continually expanding through hybridizing efforts. Understanding the sheer volume of varieties requires exploring the systematic ways these plants are classified. This article details the primary categories used to organize their range of sizes, colors, and textures, explaining the difference between wild species and cultivated varieties.
The Difference Between Species and Cultivars
The genus Hosta contains a small number of recognized botanical species, which are the original, naturally occurring forms found primarily in Asia. These species, such as Hosta sieboldiana or Hosta montana, represent the foundational genetic stock for modern varieties.
The true explosion in variety comes from the term “cultivar,” a portmanteau for “cultivated variety.” Cultivars are plants bred or selected by humans for specific traits, which are then maintained through vegetative propagation like division or tissue culture.
The American Hosta Society tracks the official count as the International Cultivar Registration Authority. The number of registered cultivars has surpassed 10,000 and is constantly increasing. Registration ensures a unique name and description are permanently recorded, which helps limit confusion among the thousands of available varieties.
Categorizing Hostas by Size
Size is one of the most practical ways hostas are classified, directly impacting their placement in the garden landscape. The American Hosta Society recognizes five primary size categories based on the mature height of the plant clump. Size classification is also refined by measuring the leaf surface area, offering a more specific metric than height alone.
- Miniature: Typically less than six inches tall, with a leaf area under six square inches.
- Small: Mature between seven and ten inches tall, often used for edging or containers.
- Medium: The most numerous category, growing between 11 and 18 inches in height, fitting well into mixed perennial borders.
- Large: Substantial plants reaching 19 to 28 inches tall, frequently serving as specimen plants. They often have a leaf surface area between 81 and 144 square inches.
- Giant: Mature at heights exceeding 28 inches, sometimes reaching over three feet tall and six feet wide. Giant varieties often have leaves exceeding 120 square inches.
Categorizing Hostas by Color and Variegation
Color and variegation provide the primary visual distinctions among hosta varieties. The base colors fall into four main categories: Green, Blue, Gold (or Yellow), and White.
Base Colors
Blue hostas achieve their color from a crystalline, powdery wax coating, known as glaucous bloom, over a green leaf. This waxy layer can be rubbed off and tends to melt away in high heat or direct sun, causing blue hostas to turn greener as the summer progresses. Gold and yellow hostas brighten dark corners. Some varieties are lutescent, meaning they emerge darker in the spring and progressively lighten to a brighter yellow or gold as the season advances.
Variegation Patterns
Variegated varieties exhibit multiple colors on a single leaf. Variegation occurs when leaf tissue lacks normal chlorophyll, revealing underlying yellow carotene or the absence of pigment (white). The two main patterns are marginal and medial. Marginal variegation displays color along the outer edge of the leaf, typically with a darker center. Medial variegation features the secondary color in the middle of the leaf, surrounded by a different color on the margin. Streaked or splashed variegation is another distinct pattern where colors appear randomly mixed across the leaf blade.
Categorizing Hostas by Leaf Texture and Form
Classification also focuses on the physical attributes of the leaf blade, adding tactile and structural diversity. “Substance” refers to the thickness and durability of the leaf tissue. Hostas with high substance, often characterized by a thick, waxy surface, are more resistant to damage from slugs and snails.
Leaf surfaces can be described as “corrugated” or “seersuckered,” referring to wrinkles or ribbing extending from the veins. This heavily textured, puckered effect, known as rugosity, is a desired trait that becomes more pronounced as the plant matures. Other forms include leaves that are “cupped,” where the edges fold inward to create a concave shape, or “wavy,” which describes an undulating margin.