Plants played key roles in history's greatest inventions, such as Eli Whitney's cotton gin and Tarzan's concept of modesty. Salute our foliage-loving forefathers with today's Groupon: for $12, you get two adult tickets (up to a $24 value), plus parking (up to a $2 value), at San Diego Botanic Garden in Encinitas (up to a $26 total value). Children 2 and younger receive free admission.

San Diego Botanic Garden envelops visitors in 37 acres of lush gardens and diverse terrain, offering nature-centric events and docent-led tours through the urban oasis. Explore the seemingly endless expanse of 28 themed gardens and venture into the world of verdure with the Australian Garden, rich in low-water plants and Vegemite, or the Mediterranean Garden, filled with fragrant water-smart plants such as lavender, rosemary, and Tang. Attend an insightful event, such as the Asian Arts in the Garden experience, or satisfy pressing cocoa queries at the Chocolate Festival. Peruse the premises with a gaggle of garden groupies, take a self-guided tour, or attend the free docent-led garden tour at 10:30 a.m. on Saturdays.