Dutch irises are brilliant flowers for October. It’s our peak month for spring-flowering shrubs in NSW and easy, hardy Dutch irises, flowering in a range of colours, complement them perfectly.
Even if to date your iris life has been limited to tall beardeds that flower with your early roses and pale mauve Algerian iris (I. unguicularis) for winter scent, you might still be familiar with Dutch iris hybrids from the cut flower aisle in the supermarket, as they are popular and long lasting cut flowers.
Dutch irises flower at knee height or a little above. Blooms are shallower and broader (around 75 millimetres) than their bearded cousins and have a gorgeous velvety texture. Colours include white, blue, purple, yellow and ever-alluring bronze.
Narrow, arching leaves are ‘channelled’, rolled inwards like a tube, when they first emerge, before flattening out and displaying their silvery, satiny lining. Plants need full sun; if grown in shade the foliage remains tightly rolled and you’ll be lucky to get flowers.
They are happiest on the cool tablelands, though, they will tolerate coastal humidity at least as far north as Sydney.
Bulbs also need good drainage, they hate being waterlogged. They prefer slightly alkaline soil and a dose of blood and bone (if you remember, but no stress if you don’t) as the leaves die down.
You can leave a clump undisturbed for several years, though, you might like to divide and replant when it becomes crowded and produces fewer flowers. Bury bulbs from late summer to autumn, pointy end up, at a depth of three times their height or 75mm-100mm, and cover with a blanket of mulch in frosty districts.
They are happiest on the cool tablelands, though, they will tolerate coastal humidity at least as far north as Sydney. They like cold winters and hot, dry summers, so New England gardeners might prefer to lift and store your bulbs over summer, taking care to keep them bone dry.
Dutch irises (Iris x hollandica) aren’t really Dutch at all, though, the glamorous hybrids available to us lucky gardeners were produced by Dutch growers, those sovereigns of the flowering bulb market. Their parentage includes several species, mostly from the western Mediterranean, hence their preference for dry summers.
For many years I have grown celestial white Casablanca, ultramarine Professor Blaauw and silvery blue and soft yellow Apollo, very vigorous.
I’ve had less luck with bronze flowers. Aptly named Autumn Princess flowered once, grudgingly, before taking off, princess-like, for iris heaven, grrr...so next year I’ll try darker bronze Lion King.
No gardener is ever satisfied, naturally, so with your Dutch irises safely established you might like to gild the lily with some ground covering Ajuga reptans, blue flowers, purple or white Honesty (Lunaria), or dwarf Comfrey, pink and white.
Heads Up: Wellington Open Gardens (www.visitwellington.com.au) October 22, 9.30am-5pm. Six gardens around historical homes commemorate the 200th Anniversary of the discovery of Wellington Valley. Admission $20 or $5 per garden. Details Jennifer Wykes, phone 0417 427 839.
Last chance: remove spent Euphorbia myrsinites flowers before their seeds take over.
