Spring warmth gave no clear change in bloom separation between two cloned honeysuckles in four US samples in 1968-1991

We tested whether March-April warmth was linked to the absolute first-bloom date separation of two cloned honeysuckle species at the same US site. We used 1,833 paired plant-years in eastern and western regions during 1968-1979 and 1980-1991. Separate models held plant-pair and year effects fixed. Slopes ranged from -0.415 to +0.167 days per C. All four uncertainty intervals included zero after adjustment for four tests. The intervals ranged in total from -1.139 to +0.871 days per C. The data did not establish a repeated change in relative onset timing. Both species had earlier-date associations in three samples under separate outcome corrections. Two exploratory sensitivity intervals excluded zero, but neither pattern repeated across all samples. Shared visits, unknown observation intervals, selected plants, sparse eastern records, few uncertainty clusters, seasonal exposure overlap, and coarse temperature cells limit inference. These records do not establish a zero response or a causal climate effect. They do not measure flowering overlap, pollinator mismatch, biodiversity loss, or pollution. The package gives the matched panel, exact source hashes, plan, all 48 fits, figures, code, and reproduction instructions. Independent sparse and dense numerical checks passed. A full raw-data repeat reproduced the panel and all model tables exactly.

phenology · honeysuckle · paired species · first bloom · spring temperature · observation bias · regional tests · null result · cloned plants