Whereas most botanical gardens expend time and money on pest control, Powell Gardens openly invites entomological abnormalities, such as 25-foot ants and 200-pound grasshoppers. Like the mutant inhabitants of a petrified forest, these wooden sculptures dominate the serene landscape throughout the summer. For two weekends in August, real exotic insects join their carved counterparts. The Butterfly Festival, which recently finished its eighth year, allows visitors to walk through a colorful cloud of converted caterpillars in a glass-domed conservatory.