Getting through the first summer, an example
Jane McGary (Wed, 03 Mar 2004 13:02:12 PST)

Jim McKenney asked,

I have a general observation to make with regard to summer dormancy in
summer humid areas. I have attempted to bring some summer dormant iris
(oncos and onco hybrids) through our humid, hot summers by digging them and
storing the dormant rhizomes under cover but otherwise in the open air in a
shaded place. Something very unexpected happens: these plants, which endure
severe drought in nature, shrivel up and dry out. Some frits seem to show
the same response here, others don't.

With the iris, bringing them into the air conditioned house seems to work
better; the rhizomes remain hard and ironically don't dry out.

This makes me wonder if the humidity isn't inducing the plants to open
their stomata and lose water - water which is not replaced by a dormant or
non existent root system.

It is often observed that many plants from alpine and arid habitats do not
flourish in parts of eastern North America where summers are hot and humid.
The converse is also true: plants from that region do not flourish, for the
most part, in the gardens of the western third of the continent. One theory
attempting to explain this is that the atmospheric humidity in the East
prevents night cooling, even though the daytime temperatures on both coasts
may be the same. The high night temperatures are theorized to be
deleterious to plants that have evolved to "shut down" metabolically after
dark, whereas those that have evolved with high humidity and high night
temperatures are said to suffer from the extreme daily fluctuation
experienced in summer-dry climates. This may relate to Jim's experience
with air-conditioning his iris rhizomes.

Regarding the fritillaria bulbs, they should never remain out of the ground
for very long. They do not have tunics and desiccate rapidly. When I lift
them and keep them out for 3 or 4 weeks for my summer sale, I put them in
plastic bags, not quite closed, with a handful of vermiculite. I cover the
trays because exposure to light causes them to change color -- probably not
too harmful. The past couple of years I've set up my bulbs in my dining
room, which is cool and dimly lit. This means no formal dinner parties in
August, but I can't get people way out here that often anyway!

Jane McGary
Northwestern Oregon, USA