Dietes grandiflora (Large Wild Iris)
Plant image

Dietes grandiflora is a tough, frost-hardy, drought tolerant plant that forms a large dense clumps up to 1½ metres tall and looks stunning in flower. This well known indigenous large wild iris is commonly grown in gardens and used in large landscapes throughout the country.

Name & classification

Botanical name:
Dietes grandiflora

Common names:
Large Wild Iris, Fairy Iris (E)
Groot Wilde-Iris (A)
Isiqungasehlati (Z)

Plant family:
Iridaceae
-

Plant categories:
Non-herbaceous Perennials; Bulbs, Corms, Rhizomes or Tubers


Name derivation & history:
The name Dietes means "having two relatives" and refers to the relationship between this genus Moraea and Iris (Dietes were once called Moraea - a closely related group - but were separated because Dietes have a rhizome, whereas Moraea have a true corm).

Grandiflora means 'large flower'.

Pictures

Features

Leaf habit:
Evergreen

Height:
1 metre

Width:
1½ metres

Plant shape:
Dietes grandiflora plants grow in dense clumps of tall tall, tapering leaves from underground rhizomes.

Leaf description:
Long, rigid, sword-shaped leaves are held in a fan shape. The leaves are dark green and may reach up to 1m long and 15-20mm wide.

Spine or thorn description:

Flower description:
The flowers are large (about 10cm across) and white with yellow nectar guides and outer tepals, and violet central segments. The flowers are held on erect, slender stems which are about 1 metre in length.

Masses of flowers appear at certain periods - often after rain in summer. The individual flowers do not last more than a couple of days, however, the plant bears so many flowers during the peak period that the plant looks most striking.

The flowers attract lots of bees and other pollinators.

This plant is occasionally called the "Fairy Iris" because the fragile white petals not only look like fairy wings, but also have a tendency to disappear mysteriously overnight!

Flower colour:
White with yellow nectar guides and outer tepals; violet central segments

Flowering months:
Sporadically all year; masses at certain times in summer (often after rain)

Fruit description:
The large wild iris fruit is a large capsule up to 45mm which is held erect and splits open to release shiny, dark brown seeds.

Seed description:
Shiny, dark brown seeds

Other distinctive features:
The plant spreads by means of its modified stems (rhizomes), which are located below the soil surface.

Habitat

Natural distribution:
It grows naturally along the eastern coastal areas of the southern Cape, Eastern Cape and southern Kwazulu-Natal.

Habitat:
It may be found in full sun or partial shade at forest margins, or in the shelter of taller shrubs on exposed slopes facing the sea.

Water requirements:
Little water required, but does best with plenty of summer water

Frost tolerance:
Hardy

Light conditions:
Sun; semi-shade; shade

Other Characteristics

Drought resistant
Wind resistant

Edibility & Toxicity

We have no confirmation that any part of this plant is edible
We have no confirmation that any part of this plant is toxic, however we urge caution as this information may be incorrect.

Ecology

Attracts insects

Other information

Uses & Cultural aspects:
It has become a popular landscaping plant due to its reliability and hardiness and is often found in parking areas at shopping centres, schools etc. It can be effectively used in mass plantings, but is also effective in mixed plantings or used as an accent plant alongside a pond or some steps.

Cultivation:
This is a popular, easy-to-grow garden plant which will grow under most conditions. The plants are both frost and drought hardy and will grow in either sun or shade. However, for best results and most flowers, plant Dietes grandiflora in full sun or light shade in well composted, well drained soil and water well in summer.

The large wild iris is easy to propagate from seed sown in spring or by dividing large clumps which spread by means of rhizomes. They multiply rapidly and are soon ready to be split again.

Similar species:
Dietes bicolor is less fan-shaped and more upright. Flowers are smaller with light yellow petals and no violet in the centre.

Notes:
There are six species of Dietes - five of which occur in South Africa - and one on an island in the Tasman Sea (between New Zealand and Australia).

Dietes bicolor belongs to the family Iridaceae (iris family). These plants are perennial herbs in the form of either rhizomes or corms. There are about 82 genera and 1700 species belonging to Iridaceae. Over half of the species of Iridaceae occur in South Africa, in 38 genera. Plants in the family Iridaceae have sword-shaped leaves which are arranged in 2 ranks (a row, especially a vertical row). The flowers are regular or irregular with 3 stamens and an inferior ovary.

References:
South African National Biodiversity Institute, South Africa.

Your notes & lists

You need to be a registered user in order to create plant lists and notes. If you have already registered, then please log in now, otherwise, register here. It will only take a moment and we won't pass your information on to anyone else.

You can then use this section to create lists of your own plants in your garden, or a list of favourite plants or simply a wish list