My lantanas need help! I have three lantana plants in my front yard, one is yellow, one is purple and the other is multicolor. They are on the south side of the house so they have no shade throughout the day. They were doing really well but recently the flowers all started wilting. All the other lantana plants I see around town look great! So why are mine wilting? How long and how often should I be watering them? Do I need to fertilize them?