Plumeria are a true semi-tropical flowering tree. Since Plumeria have a natural dormant period, this can correspond very conveniently to an indoor storage period during the winter months. Plumeria can be grown in containers, in the ground, or in containers sunk in the ground. During the months of active growth, ample sun, food and water are essential. Healthy Plumeria will bloom regularly when they receive at least 6 hours of full sun per day. Plumeria are heavy feeders and will bloom and grow with the proper amount of fertilizer. Plumeria like water, but cannot tolerate wet feet, so they must be planted in fast draining soil or in beds with adequate drainage.
In the Spring
When the night time temperatures begin to remain above 50F, Plumeria can be brought out of winter storage and "encouraged" out of dormancy.
Repotting and root pruning are optional and are performed as with any other container grown plant. Plumeria like warm and sunny locations. Some people like to sink the container in the ground. This promotes more vigorous growth, provides support, and prevents it from blowing over.
In the Summer
Summer has arrived once a lush growth of leaves have developed. Many will bloom before developing leaves and others will not. Once the leaf growth has developed, the summer regimen of care can be followed. However, in order to discourage excessive stem elongation and to promote flowering, fertilizers low in nitrogen and semi-high in phosphorous are recommended. Once again, 16-16-16, 15-30-15, 4-26-26, and 6-30-30 are excellent choices. Keep a Plumeria healthy by feeding once a month and by watering as necessary.
During exceptionally hot periods, plants in above ground containers may need thorough watering as often as twice a week. Drooping leaves can indicate a thirsty plant. As with all plants, check the soil before watering. If it's dry for the first couple of inches, water it thoroughly. As the days begin to grow shorter during September and October, some lower leaf yellowing and leaf drop is normal. If the weather cooperates in the Fall some varieties will attempt a Fall bloom cycle. Some Plumeria can still bloom into November and December! However, an early extended frost- period can damage or kill the plant.
In the Fall
Fall begins in October and feeding and reducing water will encourage the plant to go into its natural dormant period. However, it is difficult to predict the weather. Therefore, a date by which your Plumeria should be safely stored for the winter is up to your micro-climate area. By all means, if temperatures are expected to fall into the 30's the plant should be protected. Many varieties can be damaged or killed by temperatures in the low 30's or upper 20's, even for a few hours.
In the Winter
During the winter, Plumeria require very little care. In fact, "Winter care" could be considered "Winter storage". Before storage, the Plumeria can be defoliated. To date, the best technique for this is to cut each and every leaf off the plant at a point about one inch out from the branch. This will provide a good environment to combat pests and fungus. Store the Plumeria in a cool, dry and ventilated area such as a garage or shed. Temperatures should not be allowed to fall below freezing in any outdoor storage area. During exceptionally cold periods (i.e., below 30F outside), a small supplemental heater may be required. A cold greenhouse is not recommended for Plumeria storage. Some people suggest not watering them at all for the entire winter. However a small monthly spray/ mist does more good than harm. Since a defoliated Plumeria takes up considerably less space than one in full leaf, they can frequently be stacked two and three high in the storage area.