Developers are having trouble finding retailers to fill shopping centers in South Florida as businesses close and chains curb expansion plans. Three large projects in Broward County have yet to announce anchor tenants. Shopping centers are also being built in Palm Beach County, as developers report that leasing is as difficult now as it has been in years. Landlords may have to provide more incentives to tenants for the next 18 to 36 months. Jonathan Kingsley, managing director for Grubb & Ellis Co. in Boca Raton and Miami, says recovery will take some time.