Mediterranean climate (was Fritillaria raddeana)

Jane McGary
Sat, 15 Sep 2012 13:52:29 PDT
One factor that isn't being added to the discussion of water 
availability for plants is snowmelt. Plenty of bulbous plants grow in 
the foothills of high mountains, where they are lavishly watered 
during the snowmelt period (late spring to early summer) even though 
there may be no precipitation at that time. For plants in 
winter-rainfall regions, this extends the growing period 
significantly. There are also high-elevation bulbs (though not so 
many) that are dormant in winter and grow following snowmelt in 
spring, then either experience a very dry summer or summer 
thunderstorms and/or monsoon rainfall.

The best survey of this topic in connection with bulbs is "Growing 
Bulbs" by Martyn Rix (Timber Press/Croom Helm, 1983). Its chapter 4, 
"Bulb-growing areas of the world," is 50 pages long and should be 
read by every PBS member. Although out of print, the book is widely 
available second hand. I once picked up three or four copies at 
Powell's Books and shared them with friends. In fact, I wonder if I 
could obtain permission to reproduce that chapter on the PBS website? 
If enough people express an interest, I'll investigate. Could it be 
scanned and posted as a pdf?

The Pacific Northwest west of the higher mountain ranges (the 
Cascades, mostly) is often called a Mediterranean climate, but I'd 
modify that to "cool, wet Mediterranean." Brian Mathew once told me 
that the part of the world he knew that is most like the PNW is the 
Black Sea coast of Turkey, where one also finds a lot of 
early-summer-flowering bulbs such as Lilium. The Lilium species in 
the PNW are summer-flowering as well, especially L. washingtonianum, 
which grows mostly above the winter snow line.

The Portland, Oregon area, where I live, had no measurable rainfall 
this past August, and only 0.04 inch so far in September. This is 
drier than usual, however.

Despite the lack of moisture, some fall bulbs are in flower here 
today, such as Sternbergia (which can flower without any "triggering" 
moisture in nature), a number of Colchicum species and hybrids, Acis 
autumnalis and A. valentina, and three species of Prospero (formerly 
Scilla). The first flowers on Cyclamen graecum appeared today in 
their new special bed, a raised feature built of limestone tufa. 
Cyclamen mirabile is there, too.

I haven't given the bulb house its first soaking yet because 
temperatures are still in the 80s Fahrenheit most days and I don't 
think winter-growing bulbs should ever be hot and wet at the same 
time. I did clean up the dead foliage and added more gravel mulch in 
the past few weeks. Next summer I'll probably have to lift certain 
things that have increased well. One for sure is Colchicum 
'Disraeli'; I had kept it in a pot for years because it's expensive 
and hard to obtain, but once turned loose it bulked up tremendously 
and must have three dozen flowers open today. It is in the side of 
the bulb house that gets a little summer water. Most hybrid 
colchicums are fine with the kind of irrigation given to border 
plantings, but the smaller ones do fine if left dry all summer here.

Jane McGary
Portland, Oregon, USA

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