East Ventura County gets hot in the summer, but if you’re lucky enough to live near Conejo Valley Botanic Garden in Thousand Oaks, you’ve got a cool, shady — and free! — place to visit every day, filled with ever-changing flowers, shrubs and trees to keep the walk interesting. The garden is on a hill, so the paths are like wide, gentle switchbacks with lovely views at the top. There are some modestly steep climbs in places. Be sure to wear sturdy walking shoes and bring your own water. There are restrooms in the parking area, next to the adjacent Conejo Community Park. This is a good place to bring children, with a stream running through, bridges here and there, and plenty of plant diversity, from a rare-fruit orchard and oak grove to gardens dedicated to butterflies, a bird habitat, desert cactuses and succulents, herbs, Australian plants, colorful native salvia and a “Trail of Trees” (more than 50 varieties of trees planted in 2005 to restore a slope covered with invasive mustard weed). The Rare …