MSU Extension:
After last year’s (2012) drought and very warm temperatures, Michigan State University Extension expected to see more pollen cone production in conifers. This is a major concern for Christmas tree growers. However, we are also seeing heavy pollen cone production in conifers in the landscape this spring. The problem has been most acute in spruces, especially Norway and Colorado blue spruce, but we are also finding it in Douglas fir, several true fir species and pine.
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