Iris pumila 'Volts'

Iris pumila, commonly known as the Dwarf Bearded Iris, is one of the true originals of the iris world. Unlike the Dutch irises which are bulbous, Iris pumila is a rhizomatous perennial — meaning it spreads via a thick, fleshy underground stem called a rhizome rather than a bulb.

Iris pumila is also one of the parents of the SDB group (Standard Dwarf Bearded), a horticultural category that groups hybrids between the true dwarf pumila and the taller garden irises. Its wild origins on rocky, sun-baked hillsides give it exceptional tolerance of drought and poor soils — making it perfectly at home in a rock garden or on a dry sunny bank.

Floral Morphology
Each flower is composed of six tepals arranged in two whorls. For those wondering what tepals are: on most plants we see colourful petals sheltered within a green bud of tougher outer sepals, which protect the more fragile inner petals. However on some plants — irises included — the sepals and petals are indistinguishable from one another, and these are jointly called tepals.

The three outer tepals, known as falls, are broader and spatulate, while the three inner tepals, known as standards, are narrower and held upright. In the 'Volts' cultivar these are a soft pastel pink — an unusual and highly sought-after colour in dwarf bearded irises. Each flower measures approximately 5 to 8 cm in diameter and bears three petaloid style branches arching over the stamens, a defining characteristic of the iris genus.

Reproductive Biology
Iris pumila spreads vegetatively via its rhizome, which slowly extends outward to form wider clumps over time. This makes it easy to propagate by simple division after flowering. Sexual reproduction occurs when pollinators — principally bees — transfer pollen between flowers, potentially leading to seed capsule formation, though seed production can be irregular in cooler climates.

This combination of vegetative and sexual reproduction ensures the long-term persistence of the plant even in challenging, dry environments, and makes it a rewarding and low-maintenance perennial for the garden.