Dutch iris requirements
Diane Whitehead (Thu, 11 Sep 2003 12:13:22 PDT)

I thought maybe it was something simple I wasn't doing, but since no
one else is wildly successful with them (except the Dutch) I have
been driven to old books.

The British Iris Society manual suggests leaving them in the ground
and fertilizing them.

The author of Iris in the Little Garden (publ 1927), Ella Porter
McKinney, who lived in New Jersey, U.S.A., couldn't grow them.

N. Lesley Cave, who wrote The Iris in mcml, and lived in England,
wrote this: It has been said that no one garden will grow both Dutch
and English irises, and while this is an exaggeration, there is a lot
of truth in it. Dutch (and Spanish) irises require a light, warm
soil, the English, on the other hand, demand cool, moist conditions.
......... (The Dutch and Spanish) send up their leaves in autumn, and
to prevent damage to the foliage and consequent weakening of the
bulbs, they should not be planted until October. This will delay the
growth of the leaves. They should be lifted annually as soon as the
foliage has withered.

Sunset Western Garden Book (for the west coast of North America) says
this: Plant in sun 4 in. deep, 3-4 in. apart in October-November.
Bulbs hardy, but in coldest climates, mulch in winter. Ample water
during growth; after bloom let foliage ripen before digging, store
bulbs in a cool, dry place; do not let bulbs stay out of the ground
more than 2 months.

--
Diane Whitehead Victoria, British Columbia, Canada
maritime zone 8
cool mediterranean climate (dry summer, rainy winter - 68 cm annually)
sandy soil