Plumeria flowers are asexual plants, which means that each flower contains both male and female parts. After the flower blooms fall off, insects, moths and hummingbirds pollinate the stems by shaking the pollen down into the lower stem portion where it fertilizes the plant. If you don't have many natural insect pollinators, or if the flower is in a greenhouse, you can pollinate the plumeria by hand by transferring the pollen.
Things You'll Need
Hand pruners or knife
Grasp one of the flowers and examine the stalk directly beneath it. You will see a raised collar approximately 1 inch below the bloom, which is where the male part of the flower, called the anthers, resides. Cut the stem off just above this collar with hand pruners or a sharp knife. Wait one to three days before proceeding with the pollination process.
Rub the bristles of a new artist's brush over your fingers to separate them slightly. Insert the bristles into the cut stem so that they extend down into the center hole.
Move the brush bristles around gently for five to 10 seconds to knock the pollen off the anthers and into the bottom of the stem, where the ovary is located. Watch the stem closely during the next week until you see a reddish seed pod develop that looks similar to a bean pod.
Place a small piece of clear tape over the end of the stem to cover the hole and prevent additional pollination from other plants. Keep the pod at temperatures above 45 degrees Fahrenheit until the pods dry and fall off, which occurs in the fall. Collect the internal seeds and save them for replanting.
Wait until the plumeria plant develops flower blooms, which indicates the flower is ready for pollination. The best time to pollinate plumeria is in the early spring after the first blooms appear.
Always use new brushes when pollinating plumeria so you don't cross-contaminate species. If old brushes are used, boil them in water for five minutes to destroy existing pollen.