[Trillium-l] Microhabitats

Miles, Dan miles.d at lynchburg.edu
Sat Jan 17 14:28:22 CET 2015

To follow the discussion on adaptability of eastern & western American trilliums on opposite sides of the continent (or the globe):  it would be interesting to know in what microhabitats they are being cultivated where they fail or succeed. 

In the wild, trilliums do not survive a few feet outside the places where they thrive, due to subtle but critical variations in growing conditions. Surely the same applies to a significant extent even under careful attention in gardens. I agree that night temperature may be critical, if not the primary limiting factor in succeeding with the more fussy species. 

Some Trillium species and other woodland plants are found only in riparian zones and are often limited to cool, perpetually moist, north-facing slopes, even at high elevations. Even in the Smokies, you do not find Trillium vaseyi, for example, growing on uplands, no matter how rich, even in a high-rainfall zone. 

Cool air settles in low areas. On a summer evening, when I walk out of my hollow and up to my yard on the ridge less than a hundred feet higher, I notice a dramatic rise in temperature. It can be 20 degrees F cooler at night along the streams. 

T. Vaseyi thrives here at 700 ft. Above sea level on cool streambanks, but I would not expect it to do as well on the north side of my house, no matter how much attention I may give it there. I would say the same of kurabayashii. I anxiously await the emergence of this species following  planting some young plants last spring in a cool streamside position. 

All the failures I hear about western species in the East...have they been sited in the kind of cool, moist riparian habitats in which they are found in the wild?  Are they failing simply because of too-high night temperatures?  I realize that not many gardeners are blessed to have a streamside position available. I'll keep you all posted. And thank you, Russ!

Dan Miles, Virginia Piedmont, zone 7a

Sent from my iPhone

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