Hoya Carnosa vs. Kerrii vs. Pubicalyx: A Field Guide to the Most Common Hoyas

The 5-second visual test

Look at the leaf shape and the overall growth habit.

• 1Single thick heart-shaped leaf in a small pot, no vine? → Hoya kerrii leaf cutting.
• 2Vine with paired heart-shaped leaves, leaves 5–10 cm wide? → Hoya kerrii (mature vining plant).
• 3Vine with paired oval to elliptical leaves, glossy waxy texture, sometimes variegated cream-and-green or with pink edges? → Hoya carnosa.
• 4Vine with paired narrow lance-shaped leaves, dark green often with silver-grey splash markings? → Hoya pubicalyx.

What all hoyas have in common: epiphytic vines with wax flowers

Hoyas are tropical epiphytic vines — in the wild they grow up tree trunks or hang from branches, with roots taking moisture from the bark and air rather than soil. Indoors they trail or climb depending on whether you give them support. The leaves are thick, waxy, and water-storing, which makes the entire genus drought-tolerant — most hoyas are easier to underwater than overwater.

Every hoya produces the same characteristic flower structure: a spherical or hemispherical cluster (umbel) of 10–40 small star-shaped waxy florets, usually scented (sometimes overwhelmingly so at night). Flower colour varies wildly between species — pink, white, burgundy, yellow, near-black — but the structure is unmistakable. Most hoyas don't flower until they're 2–4 years old and slightly root-bound. The flowers emerge from short woody stems called peduncles or "spurs" that should never be cut off — they bloom repeatedly from the same spur for years.

Hoya carnosa — the wax plant

Hoya carnosa is the original wax plant — the species your grandmother probably had on a windowsill. Native to East Asia and Australia, it produces long trailing or climbing vines (1–3 m indoors) with paired oval to elliptical leaves about 5–8 cm long. The leaves are thick, glossy, and waxy, with a slight curve. Flower clusters are pink to white star-shaped umbels with a darker pink centre, strongly fragrant especially in the evening.

Multiple variegated cultivars exist: 'Krimson Queen' (cream and white margins with pink new growth), 'Krimson Princess' (cream centres with green margins — opposite of Queen), 'Tricolor' (similar to Princess), 'Compacta' / 'Hindu Rope' (curled twisted leaves on a tightly compact vine — looks completely different from standard but is the same species), and 'Variegata' (irregular cream variegation). All share the same paired oval leaf base shape.

• ·Leaf: paired oval to elliptical, glossy waxy, 5–8 cm long.
• ·Vine: long trailing or climbing, 1–3 m indoors.
• ·Flower: pink/white star clusters with darker centres, fragrant.
• ·Cultivars: 'Krimson Queen' (margin variegation), 'Krimson Princess' (centre variegation), 'Compacta'/'Hindu Rope' (curly twisted leaves), 'Tricolor', 'Variegata'.
• ·Most widely available hoya species; the entry hoya for most collectors.

Hoya kerrii — the sweetheart hoya

Hoya kerrii went viral when shops started selling single heart-shaped leaves potted up in tiny pots as Valentine's Day gifts. The single-leaf cutting is exactly that — a single leaf rooted from the parent plant — and it almost never grows into a full vine. Why: the leaf was cut without a node (the point on the stem where new growth emerges), and without a node there's no meristem tissue to produce a new vine. The leaf survives indefinitely on its own, but it stays a single leaf forever.

A mature vining Hoya kerrii is a different beast: long climbing vines with paired thick heart-shaped leaves 5–10 cm across, looking like rows of green hearts climbing a trellis. Flowers are creamy white star clusters with reddish-purple centres, less common indoors than carnosa flowers. The variegated cultivar 'Variegata' has cream margins on the heart-shaped leaves and grows even more slowly than the standard.

• ·Leaf: thick heart-shaped, 5–10 cm across, paired on a vine when mature.
• ·Vine: slow-growing climbing or trailing, can reach 2 m+ over years.
• ·Single-leaf cuttings: alive but won't grow without a node — buy a vining plant if you want growth.
• ·Flower: creamy white star clusters with red-purple centres.
• ·Cultivars: 'Variegata' (cream margins), 'Splash' (silvery speckles).
• ·Common name: sweetheart hoya, Valentine's hoya, lucky-heart vine.

Hoya pubicalyx — the speckled dark hoya

Hoya pubicalyx has a very different look from the other two: paired narrow lance-shaped leaves 8–15 cm long, dark green, often with irregular silver-grey or white "splash" markings on the upper surface. The vine is moderately fast-growing for a hoya — 60–100 cm per year in good conditions — and tolerates lower light better than carnosa or kerrii. Flowers are unusual and dramatic: dark burgundy to nearly black star clusters with red centres, strongly scented at night.

Several cultivars are widely sold based on flower colour and leaf splash pattern: 'Royal Hawaiian Purple' (deep burgundy flowers), 'Red Buttons' (small bright red flowers), 'Pink Silver' (pink flowers with heavily speckled leaves), 'Bright One' (heavy silver leaf speckling). All share the narrow dark lance-leaf shape that identifies pubicalyx.

• ·Leaf: paired narrow lance-shaped, 8–15 cm, dark green.
• ·Markings: irregular silver-grey or white splash on upper leaf surface.
• ·Vine: moderately fast-growing for a hoya, 60–100 cm/year.
• ·Flower: dark burgundy to near-black star clusters, fragrant at night.
• ·Cultivars: 'Royal Hawaiian Purple', 'Red Buttons', 'Pink Silver', 'Bright One'.
• ·Most tolerant of low light among the three.

Leaf shape — the single fastest ID

If you remember nothing else, remember the three leaf silhouettes.

• ·Heart-shaped leaf → Hoya kerrii.
• ·Oval to elliptical leaf, glossy waxy → Hoya carnosa.
• ·Narrow lance-shaped leaf with silver speckles → Hoya pubicalyx.
• ·Curled twisted leaf clusters on a compact vine → Hoya carnosa 'Compacta' (Hindu Rope) — same species as standard carnosa.

Side-by-side care differences

All hoyas share the same broad needs — bright indirect light, drying between waterings, well-draining mix, never repot when flowering — but the three species differ in tolerance.

• ·Hoya carnosa: bright indirect light, dry between waterings (top 3–5 cm). Tolerates more direct sun than the others. Easiest to flower indoors.
• ·Hoya kerrii: bright indirect light, very dry between waterings — most drought-tolerant of the three. Slow-growing; takes 3–5 years to reach a flowering size. Single-leaf cuttings need almost no water.
• ·Hoya pubicalyx: bright indirect light, tolerates the lowest light of the three. Faster-growing, often flowering within 2–3 years. Slightly more moisture-tolerant than the other two.
• ·All three: never cut off the bare flower stems (peduncles) after blooms drop — they bloom repeatedly from the same spur.
• ·All three: hoyas like to be slightly root-bound to flower; don't repot a hoya that's blooming or about to bloom.

Why your single-leaf Hoya kerrii isn't growing

A single Hoya kerrii leaf in a pot is almost certainly a leaf cutting — a leaf cut from the mother plant with a short stub of petiole, planted upright in soil, and rooted as a single leaf. The leaf stays alive indefinitely (decades, in some cases) but it almost never grows into a vine because it was cut without a node — the meristematic tissue that produces new stems and leaves.

If you want a Kerrii that actually vines, buy a plant that already has multiple paired leaves on a stem — that's a true vining specimen with active meristem. Single-leaf gift cuttings are essentially decorative succulents: keep them alive, enjoy the heart shape, but don't expect growth. To check: trace the petiole down to where it meets the soil. If there's no stem segment with a small bump (node) below the leaf, there's nothing to grow from.

How to actually get hoyas to flower indoors

Hoyas need maturity, light, and slight stress to bloom. Most won't flower for the first 2–4 years after rooting. The conditions that trigger blooms: very bright indirect light (the brighter the better, short of direct sun); a slightly root-bound pot (don't size up unless absolutely necessary); a brief winter dry period followed by resumed watering in spring; and patience — once a peduncle (flower spur) forms on a vine, it can bloom repeatedly from the same spot for years.

The cardinal sin: cutting off the bare flower spurs after blooms drop. Many beginners mistake the bare brown peduncle for a dead twig and snip it off — but that single spur would have flowered again the next season and every season after. Always leave peduncles in place, even when they look unimpressive between blooms.

All three are pet-safe

Hoya carnosa, Hoya kerrii, and Hoya pubicalyx are all listed as non-toxic to cats and dogs by the ASPCA. The genus as a whole is considered pet-safe. Hoya leaves are thick, waxy, and uninteresting to most pets, so chewing is uncommon even when accessible.

If you're building a pet-safe collection, hoyas are a good option for the trailing or climbing slot — most non-toxic alternatives are upright or rosette plants (Calathea, Peperomia, parlor palm), so a hoya adds vine variety without compromising pet safety. See our pet-safe houseplant guide for more options.

Common nursery mislabels

Hoyas are often labelled vaguely as just "Hoya" or "wax plant" with no species or cultivar name, especially at general garden centres. The three species in this guide are easy to tell apart by leaf shape, but the cultivars within each species cause more confusion.

• ·Hoya carnosa 'Compacta' (Hindu Rope) is sometimes sold as a separate species — it's the same species with a tightly curled leaf mutation.
• ·Hoya pubicalyx cultivars (Royal Hawaiian, Red Buttons, etc.) are often unlabelled — they're indistinguishable until they flower.
• ·A single-leaf Hoya kerrii in a pot is a leaf cutting; the label may not mention this. Don't expect growth without a node.
• ·Hoya carnosa 'Krimson Queen' (margin variegation) and 'Krimson Princess' (centre variegation) are often confused — Queen has cream/white edges with green centres; Princess has the inverse.
• ·Other species sold under "hoya" labels: Hoya bella (small clusters of paired leaves on hanging stems), Hoya obovata (large round leaves, similar to kerrii but more rounded), Hoya curtisii (small spotted lance leaves on creeping vines). When in doubt, run a photo through a plant ID app.

Choosing the right hoya for your home

If you want the easiest hoya and the best chance of flowers, pick Hoya carnosa — wide availability, robust growth, reliable bloomer with good light. The variegated cultivars ('Krimson Queen', 'Tricolor') add visual interest at slightly slower growth. If you want something striking that flowers fast, Hoya pubicalyx delivers dark dramatic blooms within 2–3 years and tolerates lower light than the other two.

Hoya kerrii is for patience. The heart-leaf shape is unique among houseplants and a mature vining Kerrii is gorgeous, but it grows slowly and takes years to flower. Single-leaf cuttings are decorative novelties — beautiful but static. Buy a plant with multiple paired leaves on a vine if you want one that will actually grow.