The Plumeria, widely known as Frangipani, is a tropical genus of flowering trees and shrubs cherished for its intensely fragrant blooms. Often associated with Hawaiian leis, these plants introduce a strong tropical aesthetic to any landscape. Their ultimate size is highly variable, depending heavily on whether they are grown in the ground or in a container, along with environmental and genetic factors.
Typical Mature Dimensions
When Plumeria grows freely in the ground under ideal, frost-free conditions, it develops into a substantial small tree. Mature specimens typically reach 15 to 25 feet in height, though some varieties can exceed 30 feet over many years. The lateral spread often mirrors the height, creating a wide, rounded canopy that requires significant space.
The size difference is apparent when the plant is grown in a pot, common in non-tropical climates. Container-grown Plumeria remains smaller, usually limited to 6 to 10 feet in height. The restricted root system severely limits the overall size of the above-ground growth. Gardeners in cooler regions cultivate them this way so they can be moved indoors for winter protection.
Key Factors Influencing Size
The broad range of Plumeria sizes is primarily determined by species, age, and growing environment. A consistently warm climate is the most important factor enabling the plant to reach its full potential. Plumeria thrives in USDA Hardiness Zones 10 through 12, where temperatures rarely dip below 40°F (4°C) and never experience a hard frost. Outside this range, in-ground plants often need severe cutting back after cold damage or must be kept small for containerization.
Genetic variation between species plays a significant role in determining final height. Plumeria rubra, the most common species, is typically the largest grower, capable of reaching 25 to 30 feet. In contrast, Plumeria obtusa, or Singapore Plumeria, is a slower-growing species that tends to top out at 10 to 15 feet. Specialized dwarf cultivars remain compact, often maturing at heights of only 3 to 6 feet.
Plumeria is a slow to moderate grower, which means it requires a significant amount of time to reach its mature size. Under optimal conditions, a young Plumeria may add between 12 and 24 inches of height per year. This relatively slow growth rate means that a specimen may take 10 to 20 years to fully develop into a large landscape tree.
Managing Height Through Pruning
Gardeners can actively intervene to control or limit the height of their Plumeria, especially if constrained by space or climate. Pruning is done primarily to maintain a desired shape and size, which is useful for container plants. The ideal time for major structural pruning is during the plant’s dormant period, typically in late winter or early spring before new growth begins.
The primary technique for height control involves heading back the branches to a desired length. Plumeria only develops new branches after the terminal tip is removed, either by flowering or pruning. Cutting a single branch tip encourages the development of two or three new branches just below the cut. This results in a bushier, more compact crown and a reduction in overall height. Excessive or drastic pruning, however, may delay flowering, as the blooms form on the tips of mature branches.
For Plumeria grown permanently in containers, height management also includes occasional root maintenance. While the plant may be repotted into a larger container every few years, root pruning is an alternative method. This involves removing a portion of the root ball and replacing the old soil with fresh potting mix. This allows the plant to remain healthy while staying in the same size pot, keeping the overall size small and manageable for display.