Possible Clues:

• Prickly types caught first part of play
• Prickly pear and saguaro, for two
• Exemplars of water conservation
• Southwestern flora
• Desert growths
• They grow in the desert
• Saguaro National Park flora
• Section of a botanical garden
• You might be stuck with these when traveling in the Southwest
• Plants needing minimal cold protected by man on island