Iris xiphium - Dutch Iris - Professor Blauw

Family: Iridaceae

Common Name(s): Spanish Iris

Native to: Spain

Flowering: Late Spring

Watering: Water well at planting time and during the growing season if dry conditions prevail; but allow the soil to dry out once the leaves die down

Planting Aspect: Full Sun, Part Shade

Preferred Climate:

 

Temperate, Subtropical, Tropical, Grassland

Description

Dutch Iris is easy to grow, multiply quite freely and bloom year after year in cool, temperate and warmer climates. Flower colour varies from white and yellows through to many shades of blue and purple in either single colour standards and falls through to a combination of both. They are very frost hardy and prefer a sunny position with ample moisture during growth, but none during their dormancy in summer. They can be grown in pots and terrace planters and are ideal as cut flowers for vases and arrangements. Dutch Iris grow to a height of 40 to 50cm.

Cultivation

Choose a sunny position in rich, well draining soil. Prepare the growing site by digging over the soil and adding a good handful of blood and bone, rich compost or well decayed animal manure prior to planting out. Plant the bulbs about 7cm deep and 10cm apart. If grown in pots and other containers, they should be planted slightly deeper and closer together for greater moisture retention and flowering effect and then place them in a brightly lit area to prevent them from getting floppy. Shortly after the foliage emerges through the soil, spread a small amount of general fertilizer with an NPK ratio of 10-10-10 over the growing area and water in.

During the growing period, Iris needs to be kept free of aphids, as they are the carriers of virus infection which will cause leaf streak and reduced flowering. Water well during the growing season if dry conditions prevail, but allow the soil to dry out once the leaves die down. After the bulbs have flowered, resist the urge to remove the untidy green foliage but allow it to die down naturally. Bulb clumps will multiply freely and can be left undisturbed for many years. Only lift and divide them in spring/summer if they appear to become crowded.