Plants for green roofs with soil depth of 50mm

Plants in this family have their flower parts in multiples of three: three sepals, three true petals and three stamens. Each capsule-like seedpod contains three chambers. Most members of Iridaceae have underground root structures such as bulbs, corms or rhizomes. Pollinated by insects, many have highly ornamental blooms and, as such, are commonly grown as garden plants and cut flowers.

Plants in this family have their flower parts in multiples of three: with three sepals, three true petals and three stamens. Each capsule-like seedpod has three chambers.

Browse our list of plants in the Iris family, below.

Crocus

There are around 90 species in the Crocus genus, of which the most commonly known to gardeners is spring-flowering Crocus tommasinianus (pictured), which is typically grown for an early splash of colour, and is popular with bees. All species in this genus are perennial and grow from corms, and flower in spring, autumn or winter. One of the most notable of the genus is Crocus sativus, which bears the long stigmas from which the spice saffron is obtained.

Sisyrinchium

Sisyrinchium is a large genus of low-growing annuals and rhizomatous perennials with grass-like leaves. They’re often called blue-eyed grasses but, despite some species superficially looking like grasses and even growing on grassland, they’re not true grasses.

The species we gardeners are most familiar with is Sisyrinchium striatum (pictured). This clump-forming perennial has grey-green, iris-like leaves from which tall, upright stems bear clusters of pale yellow star-shaped flowers. Its flowers are perfect for cutting and it's drought-tolerant, making it a fantastic garden plant.

Freesia

Freesia is a genus native to South Africa. Growing from corms, plants have extremely fragrant, usually funnel-shaped flowers. There are many cultivars bred for garden and cut-flower use. Freesia laxa (pictured) has sword-shaped leaves, from which tall stems bear racemes of open, trumpet-shaped blooms in summer.

Bearded iris

There are some 300 species in the Iris genus. One of the most popular garden varieties is the bearded iris, Iris germanica (pictured), of which there are many cultivars. They bear clusters of large, extravagant flowers from late spring to early summer. In common with the rest of the genus, bearded iris flowers consist of three upright ‘standards’ (true petals) and three ‘falls’ (sepals that look like petals). Bearded iris grow from a rhizome that sits just above the soil’s surface. Most varieties have a sweet, spicy fragrance.

Gladiolus

Gladiolus is a genus of perennials with sword-like foliage, growing from corms. They bear spikes of highly ornamental flowers. Commonly grown in the garden and cuttings patch, there are many cultivars to choose from. Gladiolus nanus (pictured) is an easy species to grow, having tall, slender stems and a graceful habit. Grow in well-drained soil in full sun.

Yellow-flag iris

Yellow-flag iris, Iris pseudacorus, is one of the few plants in the Iris genus that prefer damp conditions. It bears sulphur yellow flowers with brown markings in summer. It thrives in moist to damp soil and is perfect for growing in bog gardens or in the margins of large ponds.