General Observations and Characteristics of Plumeria Cultivars
This document details the general observations and characteristics of various cultivars within the genus Plumeria. The genus includes five or more species, but most cultivars belong to P. rubra or P. obtusa. We focus on the flower, the leaf, and the overall plant. Specific traits are considered when classifying a species or recognizing a variety. These characteristics are documented for each variety in the section on Cultivars and Varieties.
Growth Habit
Plumeria typically exhibits a well-defined growth habit but can sometimes display unusual behaviors. Similar to cats, Plumeria often defies expectations and accepted rules. For instance, while it’s generally believed that Plumeria need full sun to bloom, there are instances where they bloom in low-light conditions, like in a garage during winter. Additionally, while Plumeria are thought to need blooming to branch, there are cases where plants have numerous tips without frequent blooming.
Propagation of Plumeria can be done using cuttings, as outlined in the guide “How to Grow Plumeria from a Cutting.” Although other propagation methods exist, the plants described here usually start from cuttings.
New growth, including leaves and flowers, occurs at the branch tip. The tip’s diameter is typically the same as the rest of the branch. The young branch and its tip resemble a broomstick more than a tree branch, being soft, brittle, and full of white milky latex sap. As new leaves grow, the branch extends by adding tissue to the tip. When an inflorescence (flower bud or stalk) forms, the tip divides into one or more new tips, continuing to thrive. This process allows the Plumeria to branch. Usually, two or three new tips form, but this can vary. The length of annual tip growth depends on factors like variety, growing conditions, and nutrition.
Plumeria has evolved an annual growth cycle with a dormant period to survive droughts in its native arid tropical regions of Mexico, Central America, and the Caribbean. This dormant period aligns with the Northern Hemisphere’s winter, allowing the plant to be stored indoors during cold weather. While dormant, Plumeria requires minimal care and usually loses all its leaves.
In spring, as sunlight and temperatures increase, plumeria break dormancy by producing leaves and inflorescences on many tips. Many plumerias bloom before growing leaves. Active growth occurs after spring rains, provided temperature and sunlight needs are met. This period sees the most vegetative growth, including root regeneration, new leaves, and branch elongation. Blooming and inflorescence formation often continue during this time, and seed pods may also develop.
Drought, reduced sunlight, and cooler temperatures induce dormancy as fall approaches. Leaves yellow and drop, flowering decreases or stops, and overall growth slows or halts. Depending on environmental factors, dormant Plumeria requires temperatures above freezing and dry conditions, with dormancy lasting one to five months.
Characteristics Overview
Flowers
Plumeria flowers typically have five petals, though four, six, seven, or more petals are not uncommon. Some flowers do not fully open and are referred to as shell, semi-shell, or tulip-like. Most flowers emit a strong, pleasant fragrance, most intense in the early part of the day. Fragrance descriptions are subjective and vary with environmental and nutritional factors. Color descriptions are more precise, with primary plumeria colors including white with a yellow center, yellow, multicolor, pink, and red. Reds are often more accurately described as red-purple.
Leaves
Plumeria leaves are generally green but exhibit remarkable variation depending on species and variety. Leaf descriptions focus on shape, color, size, and texture.
Plants
Plumeria is best classified as a tree and can grow over thirty feet tall in tropical climates. Mature plumerias have strong hardwood and can support a person’s weight if branches are at least three inches in diameter. We consider the general growth habit of a variety, its branching tendencies, seed-bearing potential, and suitability as a container, ornamental, or landscape plant.
Characteristics in Detail
Flowers
Flower measurements compare varieties against each other. When applicable, universal standards like rulers or color charts are used; otherwise, comparisons are among peers.
Petal Colors: We aim for accurate colors using advanced digital imaging. Temperature affects red and red-purple pigmentation intensity, with warmer climates intensifying these colors.
Size: Flower size is determined by measuring the distance between the most distant petal tips. This average can vary significantly due to plant maturity, environment, and flowering cycle stage.
Petal Texture: Subjectively measured on a zero to three scale, with zero being fragile, one delicate, two strong, and three rigid. Flowers with thick petals are generally longer-lasting and better for leis.
Fragrance: Subjectively measured, typically described as “plumeria” or “floral sweet.” When possible, other descriptive terms are used.
Intensity of Fragrance: Rated on a zero to three scale, with zero for no fragrance, one for light, two for moderate, and three for heavy fragrance.
Tendency to Fade: Fading, usually due to UV rays, is rated as none, slight, moderate, or dramatic.
Petal Type: Described by shape, tip, and unique characteristics, including elliptical, obovate, and rarely spatulate, further classified as wide or narrow. Other factors include reflexed or twisted petals and round or pointed tips.
Flower Type: Some blossoms do not open entirely and are classified as shells or semi-shells.
Leaves
Leaf characteristics aid in variety identification, focusing on color, texture, border color, petiole color, shape, length, width, and striation.
Color: Typically green, with variations including purplish or blackened tints.
Texture: Describes rigidity, with leaves classified as flexible or rigid.
Leaf Border Color: The edge may show colors like red, indicating a variety of heritage.
Petiole Color: Usually green or with a reddish tint.
Leaf Shape: Described as elliptic, oblanceolate, or lanceolate, with tips classified as acuminate, acute, or obtuse.
Leaf Length and Width: Measured for a typical mature leaf, not including the petiole.
Variegation: Some varieties show variation, as mentioned when observed.
Plants
Overall, plant characteristics relate to suitability as ornamental, container-grown, or landscape plants and provide genetic information for hybridization.
Pollen Parent: The male parent, if known.
Seed Parent: The female parent, if known.
Deciduous or Evergreen: Deciduous plumeria drop most of their leaves during dormancy, while so-called evergreen varieties grown in tropical regions retain leaves and minimize the dormancy phase.
Seed Production: Rated as none, rare, seldom, average, or profuse.
Branching: Based on the number of new tips after an inflorescence, rated from one to five.
Growth Habit: Described subjectively as dwarf, compact, medium, tall, upright, rangy, lanky, or dense.
Trunk Circumference: Measured 300 cm from the ground to indicate specimen maturity.
The Standard Reference
The standard reference is the Royal Horticultural Society Colour Chart, recognized worldwide.
Using the Standard Reference
Use the color chart in daylight, not direct sunlight, but in a bright, shady spot. Most plumeria reds are found in Fan 2 of the Red-Purple Group. Select a fully opened blossom, avoiding significant fading. Tear a petal, draw its outline on paper, and mark color areas. Cut the petal into pieces of uniform color and match them to the color chart. Annotate the drawing with color codes and describe the petal incorporating these codes. This technique is used for color descriptions in Cultivars and Varieties.
Detailed Characteristics
Flowers
Petal Colors: Using advanced digital imaging, we strive to represent colors accurately. Temperature significantly influences the intensity of red and red-purple pigments, with warmer climates enhancing these colors.
Size: Flower size is measured by stretching an average floret to its maximum width and recording the distance between the furthest petal tips. This average can vary significantly due to factors like plant maturity, environment, and flowering cycle stage.
Petal Texture: This is subjectively measured on a scale from zero to three, where zero indicates fragility, one delicacy, two strength, and three rigidity. Generally, thicker and more rigid flowers are longer-lasting and better suited for leis.
Fragrance: The fragrance of plumeria flowers is another subjective measure. While many plumeria enthusiasts describe the scent as simply “plumeria,” we use terms like “floral sweet” or other descriptive terms when appropriate.
Intensity of Fragrance: This is rated on a scale from zero to three, with zero indicating no detectable fragrance, one for light to mild fragrance, two for moderate to strong fragrance, and three for heavy fragrance.
Tendency to Fade: Fading, often caused by UV rays, is most apparent in red-purple pigments but can also affect pinks and yellows. This tendency is rated as none, slight, moderate, or dramatic.
The intensity of Flower Color: UV rays and heat can often enhance the colors and details of plumeria petal colors.
Petal Type: Petals are categorized by their shape, tip, and unique characteristics. Categories include elliptical, obovate, and rarely spatulate, with further classifications as wide or narrow. Additional characteristics include reflexed or twisted petals and round or pointed tips.
Flower Type: Some plumeria blossoms do not fully open and are classified as shells or semi-shells.
Leaves
Color: While most plumeria leaves are green, variations can include purplish tints or blackening. Descriptions typically include light green, green, or other noteworthy aspects.
Texture: This describes the rigidity of the leaf, with classifications as flexible or rigid based on how easily the leaf bends. A leaf held by its petiole (stem) and waved slowly back and forth is classified as flexible if it shows significant distortion from its plane due to air resistance and rigid if it retains its shape. Nearly all plumeria leaves are glabrous (smooth and not hairy), although some rare exceptions exist. The bottom surfaces of most plumeria leaves are also considered glabrous, even though they may be bumpy with exaggerated veins.
Leaf Border Color: The extreme edge of the plumeria leaf may exhibit colors other than green, frequently red, which can indicate the variety’s heritage.
Petiole Color: The petiole, or leaf stem, is usually green or green with a reddish tint, which may also indicate the variety’s heritage.
Leaf Shape: The shape, size, and type of tip of the plumeria leaf are essential for identifying varieties and understanding their heritage. Leaves are described as elliptic, oblanceolate, or rarely lanceolate. These descriptions can be refined as wide or narrow as necessary. The leaf tip is described as acuminate, acute, or obtuse.
- Elliptic: The widest part of the leaf is near its center.
- Oblanceolate: The widest part of the leaf is nearer its tip than its center.
- Lanceolate: The widest part of the leaf is nearer its petiole than its center.
- Acuminate: The leaf edge curve abruptly changes as it narrows near the tip.
- Acute: The leaf edge curve does not significantly change as it narrows near the tip.
- Obtuse: The leaf has a very blunt tip that does not usually come to a point.
Leaf Length and Width: A typical mature leaf is measured for length and width, excluding the petiole. The width is measured at its widest point. The ratio of length to width may be more significant than the absolute measurements.
Variegation: Some plumeria varieties exhibit light to moderate random changes in leaf coloration, referred to as variegation. This characteristic is noted when observed due to its rarity.
Plants
Pollen Parent: The name of the male parent, if known.
Seed Parent: The name of the female parent, if known.
Deciduous or Evergreen: Deciduous Plumeria usually drop most, if not all, of their leaves during a dormant period. Evergreen Plumeria either retain most of their leaves while dormant or do not experience an annual dormant period. In subtropical climates where evergreen Plumeria are stored indoors for winter, most varieties go dormant and drop their leaves.
Seed Production: Based on experience, observation, and advice from others, seed production is rated as none observed (not known to have ever set seeds), rare (once), seldom (unusual but occasional), average (at least once a year), or profuse (much more than average). This rating relates to how many seed pods a mature specimen produces under ideal conditions.
Branching: This characteristic is based on observing how many new tips grow after an inflorescence is produced. We examine a specimen of the given variety and note the usual number of new tips. This typically ranges from one to five, and we apply our opinion of the variety’s branching habit:
- Poor: Few new tips.
- Fair: A moderate number of new tips.
- Good: A significant number of new tips.
- Excellent: A high number of new tips.
Growth Habit: A subjective description of the plant’s stance, which environmental and nutritional factors can influence. Growth habits are described as:
- Dwarf: The shortest and most compact growing Plumeria with small leaves and usually small flowers.
- Compact: A smaller plant with a better branching habit and minimal stem elongation before blooming and branching again.
- Upright: Describes the plant’s attitude, specifically the angle at which new tips emerge from an old tip after blooming. A wider angle results in a more upright appearance.
- Rangy: Describes the plant’s attitude with narrow angles of new tips emerging from old tips, sometimes curving before blooming and branching again. Rangy plants often have significant stem elongation before blooming and branching again.
- Lanky: Typically larger plants with more stem elongation before blooming and branching again, usually applied to upright plants rather than rangy ones.
- Dense: Refers to the relative closeness of branches to each other. This is a subjective opinion rather than a measurement and can be used with other growth habits in seemingly contradictory ways, such as rangy and dense.
Trunk Circumference: Measured approximately 300 cm from the ground to indicate the relative maturity of the specimen examined.
The Standard Reference
The standard reference used is the Royal Horticultural Society Colour Chart. This society is recognized worldwide and makes its color chart available worldwide.
Using the Standard Reference
The color chart should be used in daylight, not in direct sunlight, but in a bright, shady spot. Most plumeria reds are found in Fan 2 of the Red-Purple Group.
- Select the Blossom: Choose a fully opened blossom that has not significantly faded. This is typically one or two days after it begins to open. Some varieties may have already begun to fade, which cannot be helped.
- Outline the Petal: Tear a single petal from the blossom. Lay it on a clean sheet of paper with the top side up and the petal tip pointing upward. Draw its outline with a pen or pencil. Flip the petal over and repeat this process elsewhere on the same sheet.
- Analyze Color Bands: Examine the petal closely and determine its significant areas of banding, striping, and differing colors. Draw these areas within the petal outlines on the sheet.
- Cut and Match Colors: Cut the petal into pieces containing only one significant color using scissors. Match each piece to the color chart by narrowing down the options and selecting the best match. An exact match is rare; hue is more important than intensity. Annotate the drawing with the color chart code for each area.
- Describe the Petal: After marking all areas, describe the petal in narrative form, incorporating the appropriate color codes. This technique is used for color descriptions in Cultivars and Varieties.
Summary
Understanding the detailed characteristics of plumeria cultivars, including their flowers, leaves, and overall plant structure, is essential for accurate identification and classification. The Royal Horticultural Society Colour Chart provides a standard reference for color descriptions, ensuring consistency and accuracy in documenting the beautiful diversity of plumeria varieties.
Obtaining the Standard Reference
The Plumeria Place has no affiliation with the Royal Horticultural Society. This information is believed to be correct but can not be guaranteed. Given the aforementioned, the color chart can be obtained by snail mail. The cost is about $35.00 US and it is believed Visa and Master Card are accepted. Send request and credit card information to:
RHS Enterprises
Wisley, Woking,
Surrey. GU23 6QB
England
