Bearded Iris

The bearded iris is a beautiful flowering perennial that blooms in gardens in spring to early summer. Some repeat flower in autumn (known as remontant). In warm climates iris may begin flowering in late winter.

While individual flowers only last a day or two, each stem produces multiple flowers and each clump can have several stems extending the flower show over many weeks.

Commonly grown irises have dark purple, yellow or white flowers but there are many colours and colour combinations including pink, orange, brown and blue. Petals may also be frilled or double adding to their appeal.

The iris flower is made up of three upright petals (known as standards) and three hanging petals (known as falls). The falls have a raised ‘fuzzy’ section, which give these flowers the common name of ‘bearded’.

Bearded irises grow from rhizomes, which are positioned close to the soil surface so they are slightly exposed to the sunshine. Rhizomes produce fans of tall rigid light green leaves. Clumps increase as the rhizome grows and can be lifted and divided every three years to propagate more plants and to avoid overcrowding.

Bearded iris plants combine in a planting with other perennials, bulbs including liliums, and with shrub roses.

Growing conditions

Aspect Choose a full sun position with protection from strong winds. Some tall varieties may need to have their flowering stem staked to avoid wind damage.

Soil Irises need very well-drained soil. Avoid heavy mulching around the rhizome and keep plants free of weeds. While irises are tolerant of a wide range of soil they grow best with a neutral pH (6-7).

Climate Iris thrives in temperate climates but tolerate summer heat so do well in inland and also coastal gardens. They are generally frost tolerant.

General care

Watering Adequate and regular water is important especially in spring and summer but do not over water. Too much water (for example prolonged heavy rain) or poorly drained soil can cause the rhizome to rot. In poorly drained soil, grow iris in raised beds.

Feeding and mulching Feed irises growth with a liquid fertilizer such as PowerFeed PRO SERIES for Roses & Flowers or PowerFeed All Purpose including Natives every two weeks until the flowers have finished. Feed irises as flowering ends and until foliage dies back with a granular fertilise such as Seasol plus Nutrients for Roses & Flowers.

Spread mulch such as lucerne, sugar cane or straw around bulbs to deter weed competition. Add well-rotted manure and Seasol Plant + Soil Booster to the mulch for extra nourishment and to improve the soil. Avoid a buildup of organic mulch around the rhizome.

Pruning and dividing Remove spent flowers as they finish then cut off spent flower stems once all the buds have opened. Cut stems at the base of the clump.

Remove yellowing or spotted leaves when noticed, pulling them off gently and cleanly from the rhizome. Iris foliage can be cut back in late summer or autumn to tidy the plant or if they are being lifted to be divided or transplanted.

To divide iris, lift the rhizome, cut back the leaves to form a short fan and cut out any old or damaged portions of the rhizome. Divide the rhizome so each piece has at least one or two growth points. Replant into rejuvenated soil (for example dig in compost) covering the roots but exposing the top of the rhizome to the air.

Watch for Discoloured or spotted foliage may indicate fungal disease. Apply Seasol to help improve plant health and remove competing plants and weeds that may be overcrowding the plant and shading the rhizome. Gently pull off disease-affected leaves or cut back the entire plant.

Snails and slugs may attack the flowers so keep an eye on new shoots and emerging flower stems.