2076 WWW.CROPS.ORG CROP SCIENCE, VOL. 50, SEPTEMBER– OCTOBER 2010 RESEARCH P eriods of prolonged drought and water shortages through- out the United States have resulted in an uncertain future concerning water resource availability. Water use for the mainte- nance of urban plant vegetation may result in a threefold increase in domestic water use during the summer months (Kjelgren et al., 2000). In arid regions of the United States, 40 to 45% of residential water use is applied to the irrigation of urban landscapes (Devitt and Morris, 2010). To improve water conservation, municipalities have explored ideas to help allocate and conserve water supplies. Strategies focused on residential lawn irrigation and adherence to recommended drought tolerant plant lists have been encour- aged. Water restrictions focusing on amenity turfgrass systems have become a critical component of many state and local water contingency plans. Due to home consumers’ heavy reliance on the presence of green tissue to determine plant health, irrigation is frequently initi- ated at the frst sign of leaf wilt. The inability to distinguish between drought stress and plant survivability can lead to the misuse of water resources. The inability to maintain green ground cover during droughty periods has caused municipalities and water districts to reconsider turfgrass species and cultivar selections available for home Drought Response and Recovery Characteristics of St. Augustinegrass Cultivars K. Steinke,* D. Chalmers, J. Thomas, R. White, and G. Fipps ABSTRACT As water resources become restricted for use on amenity turfgrass systems, the inability for consumers to delineate incremental drought stress relating to plant health can result in the misuse of water resources during drought con- ditions. Seven cultivars of St. Augustinegrass (SA) [Stenotaphrum secundatum (Walt.) Kuntze] and two root zone depths were evaluated for drought response and recovery during consec- utive 60-d drought and 60-d recovery periods over 2 yr. Using digital image analysis, drought response and recovery were quantifed as the number of days to decrease or increase to 50% green ground cover, respectively. Both study years provided unique conditions for investi- gating drought response as the mean time to reach 50% green ground cover differed by 24 d between the 2 yr of study. Some SA cultivars lost 50% green ground cover in 23 d while other cultivars lasted the entire 60 d drought period without losing 50% green ground cover. Flo- ratam provided the most consistent drought response and recovery compared to other SA cultivars. Once water was no longer limited, cul- tivars demonstrated up to a 52 d difference in attaining 50% green ground cover. Results could signifcantly impact home consumer irrigation behaviors and infuence consumer expectations of turfgrass following drought conditions. K. Steinke, Dep. of Crop and Soil Sciences, Michigan State Univ., East Lansing, MI 48824. D. Chalmers, J. Thomas, and R. White, Dep. of Soil and Crop Sciences, Texas A&M Univ., College Station, TX 77843. G. Fipps, Dep. of Biological and Agricultural Engineering, Texas A&M Univ., College Station, TX 77843. Received 28 Oct. 2009. *Corre- sponding author (ksteinke@msu.edu). Abbreviations: PET, Potential evapotranspiration; SA, St. Augustinegrass; SAWS, San Antonio Water System. Published in Crop Sci. 50:2076–2083 (2010). doi: 10.2135/cropsci2009.10.0635 Published online 16 June 2010. © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.