Upcountry, the coolest place to visit may be the Wrigley Memorial and Botanical Garden (Avalon Canyon Rd., 1.5 miles west of town, 310/510-2595, daily 8 a.m.–5 p.m., adults $5, children free). Stroll through serene gardens planted with flowers, trees, and shrubs that are native to the California or even to Catalina  specifically.
You’ll see a number of endangered species among the unique plants that grow nowhere else in the world. The temperate climate on Catalina lends itself to hardy, drought-tolerant species that still manage to produce beautiful colors and fragrances. Just don’t eat (or let your kids eat) the wild tomatoes—they’re incredibly poisonous! Also don’t bother with the Catalina cherries. They’re not deadly, but they don’t taste too good.
At the center of the garden you can’t miss the Wrigley Memorial, an edifice dedicated to the memory of chewing-gum magnate William Wrigley, Jr. Wrigley adored Santa Catalina Island , and used his sticky fortune to make many improvements to it; most notably, he funded the building of the Avalon Casino .
The monument is made and decorated with mostly local materials; the crushed stone on the facade comes from the island, as do the blue flagstones, the red roof tiles, and the brightly colored decorative ceramic tiles. All the local-centric construction makes a perfect centerpiece to the gardens.
For a more thorough look at the history, culture, and diverse natural abundance of Catalina, visit the Interpretive Center (Avalon Canyon Rd.) just down the road from the botanical garden. Here you can learn more about the native plants, indigenous people, and the ocean channel and its islands (of which Catalina is the most visited).