Orchids are unlike many other kinds of plants because they do not require soil in order to grow and form their blossoms. In areas where the winters rarely have freezing temperatures, you can grow many types of orchids on trees. If you live in a subtropical or tropical climate, you can experiment with growing orchids on trees, where they will offer an unexpected flush of color when they bloom. If your winters are colder, you can hang orchids from trees in hanging baskets during the warmer months and then move them indoors in fall. Hanging an Orchid On a Tree Step 1 Choose a tree with sufficient foliage to give your orchid filtered sunlight during all seasons of the year. The East Everglades Orchid Society in Florida recommends oak trees for Cattleya species and some Brassicas. Other orchids, such as those in the Schomburgika genus, can tolerate more sun and do well when you mount them on palms and other trees that have an open canopy. Mango trees and avocados are also well-suited for growing certain types of orchids, such as flat-leaf Oncidiums, Phalaenopsis and Cattleya. Step 2 Mount your orchid on a part of the tree that is open and has good air circulation. Spring is the best time of year to mount orchids to trees. If you need to protect your orchid from cold northerly wind, mount it on a branch or part of the trunk that faces south. Tie your orchid to either a vertical or horizontal branch with nylon string or green nursery tape. Step 3 Remove the tape or string about …