Washington State, along the Columbia River, climate just slightly cooler and wetter than the Willamette Valley in Oregon. I cannot get a mimosa to grow in my yard, and have noticed that established trees have died in the past five years in my area. Also, seeds dropped from existing older trees almost never take root here, unlike Philadelphia where I grew up which had them growing as weeds in yards. (I brought seedlings with me twice from visits, and they died immediately.)
What's going on here?
