Observations of flowering phenology in Concord, Massachusetts, USA, 1963-1993

Phenology plays a vital role in understanding the impacts of climate
change on plants. Observing and recording the dates that plants are in
flower, over periods of years and decades, can elucidate patterns in how
plants respond to warming temperatures, shifting precipitation regimes,
and other effects of a changing climate. Long-term records of plant
phenology are difficult to find. It is often the case that these records
do not originate from scientific research studies but instead are the
product of an individual’s interest in observing natural phases in their
local environment. Pennie Logemann (1918-2011) was a resident of Concord,
Massachusetts, United States and a landscape designer. From 1963-1993 she
recorded the flowering times of plants in her woodland garden, resulting
in an invaluable dataset of wildflower and shrub phenology. These plants
were primarily local native plants, but included some non-native species
as well.  Most likely her garden contained a mixture of species
occurring naturally on her property and species planted deliberately.
Logemann’s records have been analyzed in compilation with observations
made by Henry David Thoreau and contemporary researchers in a study of
recent climate change in Concord. The dataset provided here includes
flowering phenology records for 71 species over 30 years (discontinuous
for most species) at a single location. We encourage the use of these data
in further studies of plant phenology and hope they may provide
encouragement for others to record and share their phenology data.