212 | wileyonlinelibrary.com/journal/wre Weed Research. 2020;60:212–220. © 2020 European Weed Research Society 1 | INTRODUCTION Efforts to manage invasive weeds are often hampered by insufficient knowledge of the weed's biology in the exotic range (Jäger et al., 2009; Bennett et al., 2011). Foliar development and leaf lifespan are important elements of growth models for individual plants (e.g. Kikuzawa, 1991). Longer leaf longevity should increase primary pro- ductivity per tree by increasing the number of mature leaves per tree that have reached their full photosynthetic capacity (Kikuzawa and Lechowicz, 2011). Although the capacity to produce large canopies of actively photosynthesising leaves is typical of successful inva- sive plants (Rejmanek, 1996), little is known about leaf phenology of many non-indigenous plant species (Geiger et al., 2011), including the invasive Schinus terebinthifolia Raddi (Brazilian peppertree). In this study, we examined leaf phenology of S. terebinthifolia as part of an effort to develop a biological control programme for this weed in Florida. Schinus terebinthifolia is a dioecious tree native to Brazil, Argentina, Uruguay and Paraguay (Ewel, 1986). It was intro- duced to Florida in the 1840s and successfully colonised 35 Florida counties after escaping cultivation. It is also invasive in southern California, southern Arizona, Texas and Hawaii and has naturalised in over 20 countries (Ewel, 1986; Wunderlin et al., 2016). The Florida Exotic Pest Plant Council lists S. terebinthifolia as a noxious weed that poses a threat to native plant species throughout its invaded Received: 9 July 2019 | Accepted: 14 February 2020 DOI: 10.1111/wre.12414 ORIGINAL ARTICLE Foliar lifespan, phenology and seasonal dynamics of the invasive shrub Schinus terebinthifolia Brian N. Hogg 1 | Keith Stokes 1,2 | Min B. Rayamajhi 3 | John Geiger 4 | Paul D. Pratt 1 1 Invasive Species and Pollinator Health Research Unit, USDA-ARS, Albany, CA, USA 2 Cooperative Research, Extension, and Education Services, Northern Marianas College, Saipan, Commonwealth of the Northern Mariana Islands, USA 3 Invasive Plant Research Laboratory, USDA- ARS, Fort Lauderdale, FL, USA 4 Department of Biological Sciences, Florida International University, Miami, FL, USA Correspondence Brian N. Hogg, USDA-ARS, 800 Buchanan Street, Albany, CA 94710, USA. Email: brian.hogg@ars.usda.gov Funding information South Florida Water Management District Subject Editor: Brian Schutte, New Mexico State University, Las Cruces, USA Abstract Schinus terebinthifolia is a dioecious tree native to South America that has become an invasive weed in Florida, southern California, southern Arizona, Texas and Hawaii and has been naturalised in over 20 countries. Biological control is considered a viable long-term control option for S. terebinthifolia because release from natural enemies appears to be at least partly responsible for its success in Florida. We examined leaf phenology of S. terebinthifolia over a period of 15 months at five sites in central and southern Florida to provide information that may help in predicting the impacts of potential biocontrol agents for this weed. We documented leaf lifespan, the season- ality of leaf development and abscission and the survivorship of leaves that emerged during either spring, summer or autumn. Average leaf lifespan was >4.5 months at all sites, and leaf phenology followed the seasons closely. Although S. terebinthifo- lia possesses leaves throughout the year, leaf production was greatest from April to September, and most leaves were abscised in February and March. Spring- and summer-emerging leaves were also longer-lived than leaves produced during autumn. These results suggest that leaves of S. terebinthifolia would be most vulnerable to herbivory during the spring and summer months when newly growing leaf tissue is most plentiful. Biocontrol agents capable of damaging these tissues during spring/ summer might be an effective means of controlling this invasive weed. KEYWORDS Anacardiaceae, leaf phenology, leaf emergence, seasonality, leaf lifespan