- Graduate student Carol Petricevic has created a common garden at HPEC as part of her research into the roles of local adaptation and phenotypic plasticity in spread of the exotic invasive plant, garlic mustard. Garlic mustard is spreading southward and into the local area. Plants are being grown from seeds taken from populations from New York south to Georgia. Carol hopes to determine if the populations differ in their response to temperature and growing season length. Differences suggest local adaptation, while similar responses among populations suggest phenotypic plasticity contributes to the spread of garlic mustard.