Identity & taxonomy
- Scientific name
- Hoya kerrii Craib
- Family
- Apocynaceae
- Genus
- Hoya
- Order
- Gentianales
- IUCN status
- Least Concern (LC)
- Wikidata
- Q1633527
- Sweetheart hoyaen
- Valentine hoyaen
- Heart leaf hoyaen
- Lucky-heart planten
- Hoya kerriien
- Hjärtblad-Hoyasv
- Hjertebladno
- Hjertehoyada
- Sydänkasvifi
- Herzblatt-Hoyade
Southeast Asia — Thailand, Cambodia, Laos, southern China (Yunnan), Vietnam, and Java
How to identify it
Growth habit. Slow-growing succulent vine. In the wild, climbs trees in tropical lowland and montane forest via slender trailing stems that produce occasional adventitious roots. Indoors typically grown trailing from a hanging pot OR climbing a small trellis. Each leaf emerges in pairs from a node along the wiry stem; mature stems are pencil-thick and slightly woody. Growth is genuinely slow — typically 1–3 new leaves per growing season under good conditions, occasionally accelerating to 6–10 leaves with very bright light. The species rewards patience: a 5-year-old well-grown Hoya kerrii is about as full as a 1-year-old pothos.
Leaves. Thick succulent heart-shaped (cordate) leaves 5–8 cm long and 5–7 cm wide on short petioles 1–2 cm long. The blade is fleshy, slightly waxy, and stores water — leaves are 3–5 mm thick. The 'heart' apex points away from the stem, with the deep notch where the petiole attaches. Colour is mid-green; variegated cultivars have cream-yellow margins or centres. Underside is paler matte green. Leaves are arranged in opposite pairs along the stem (a key feature distinguishing Hoya from the alternate-leaved aroids).
Flowers. Mature plants produce dramatic spherical clusters (umbels) of 15–25 small star-shaped flowers, each ~1 cm across. Flowers are creamy white with a bright pink-red waxy central crown. Strongly fragrant — a sweet vanilla-and-cocoa scent, especially in evening. Flowering occurs on specialised bumpy stems called 'peduncles' that re-bloom annually for years; never cut these off. Indoor flowering is uncommon and requires a mature plant (5+ years), bright direct light, slight pot-bound stress, and consistent watering through summer.
- Thick succulent (3–5 mm) heart-shaped leaves arranged in opposite pairs.
- Slow-growing wiry vining stem.
- Dramatic fragrant umbel flowers on mature plants (rare indoors).
- Persistent flower peduncles that rebloom annually — never prune off.
- Pet-safe: ASPCA confirms Hoya non-toxic to cats and dogs.
Commonly confused with
Wax plant / Porcelain flower
Closely related, same genus. Differences: carnosa has elliptic-to-oval leaves (NOT heart-shaped), faster growth, and produces flowers more readily indoors. The most common Hoya in Nordic trade. If your 'sweetheart hoya' has elongated rather than heart-shaped leaves on the older growth, it's actually carnosa.
Velvet anthurium
Heart-shaped leaves but completely different texture (matte velvet, not succulent), thinner blades, and self-heading rosette habit (does not vine). Different family entirely (Araceae). Crucially, Anthurium is TOXIC; Hoya kerrii is pet-safe.
Heart-leaf philodendron
Heart-shaped leaves but thin and papery rather than succulent; faster vining growth; aerial roots from each node. Different family (Araceae). Toxic to cats and dogs.
String of hearts
Same family (Apocynaceae) and similar 'string' growth habit but with much smaller heart-shaped leaves (1–2 cm) on long thin trailing stems. Silver-green variegation with purple undersides. Closer in growth pattern to a string-of-pearls than to Hoya kerrii.
Care
Light
Bright indirect to some direct sun — more light = more chance of bloom.
Place directly in front of an east window for gentle morning sun, or 0.5–1.5 m back from a south or west window. Hoya kerrii tolerates more direct light than most houseplants (the thick succulent leaves prevent dehydration), and bright light is the single biggest factor in encouraging flowering. Direct midday summer sun is too much — provide a sheer curtain. In Nordic winters most apartments are too dim for active growth; the plant essentially sleeps from October through February. A grow light at 12 hours/day is helpful but not essential — slow winter-rest is normal for the species.
Seasonal: Move closer to windows in winter; pull back from direct summer sun.
Water
When the soil is fully dry — every 10–21 days.
Water thoroughly until water runs from the drainage holes, then empty the saucer. Allow the soil to dry fully between waterings — Hoya kerrii is succulent and stores water in its thick leaves; overwatering is the most common cause of failure. The leaves go slightly soft and lose their gloss when the plant is genuinely thirsty (this happens slowly — over weeks, not days). Use room-temperature filtered water or rainwater.
Seasonal: Reduce frequency to every 21–35 days in winter; the plant essentially sleeps and uses very little water.
Soil
Free-draining mix — cactus/succulent mix or aroid mix with extra perlite.
Use a free-draining mix: 50 % cactus/succulent soil + 25 % perlite + 25 % orchid bark, OR a standard aroid mix with an extra 25 % perlite added. The mix should drain freely within seconds; soggy soil rots the roots quickly. Some growers grow Hoya kerrii entirely in LECA (semi-hydroponics) — the species adapts well.
Humidity
40–60 % preferred — tolerates 30 % comfortably.
Among the most humidity-tolerant tropical houseplants. Ordinary apartment humidity is fine; no humidifier required. Higher humidity gives slightly faster growth and more reliable flowering, but is not necessary for survival or general health.
Temperature
16–28 °C; damage below 10 °C.
Tropical lowland species; tolerates a slightly cooler night dip than most aroids (down to 12 °C briefly) but prolonged temperatures below 10 °C cause leaf drop and stem damage. Slightly warmer summer temperatures (24–28 °C) encourage growth and flowering.
Fertilizer
Half-strength balanced or bloom-formula liquid feed every 4–6 weeks in growing season.
A balanced liquid fertiliser (NPK 10-10-10 or 20-20-20) at half label rate, every 4–6 weeks from April through September. To encourage flowering, switch to a higher-phosphorus 'bloom' formula (NPK 5-10-10 or similar) in late spring through summer. Do not feed dormant winter plants.
Seasonal: No feeding from October through March.
Pruning
Minimal — but NEVER cut off the spent flower peduncles.
The single most important pruning rule: when flowers fade, the bumpy stem they grew from (the 'peduncle' or 'spur') stays on the plant and produces new umbels of flowers in subsequent years. New growers often mistake spent peduncles for dead stems and cut them off, ending the plant's flowering career for years. Otherwise pruning is minimal — pinch back leggy stems to encourage branching, but Hoya kerrii grows so slowly that aggressive pruning is rarely needed.
Repotting
Every 3–4 years in spring; thrives slightly pot-bound.
Hoya kerrii actively prefers a snug pot — over-potting slows growth further and reduces the chance of flowering. Move up by a single pot size only when roots have completely filled the current pot. Spring is best, before the main growth flush.
Stem cuttings — node cuttings (must include a node)
easy~Roots in 4–10 weeksTake a stem cutting with at least one node and ideally two leaves. CRITICAL: a single leaf with no stem will NOT grow into a plant — it has no growth point. Place the cutting in water, sphagnum moss, or a free-draining mix at 22–25 °C with bright indirect light. Roots emerge in 4–10 weeks. Pot up once roots are 3–5 cm long. Be patient — Hoya kerrii is slow at every stage.
Layering
easy~Roots in 6–12 weeksPin a length of trailing stem against a tray of damp aroid mix or sphagnum moss with a small wire hoop, leaving the leaves above the substrate. Roots form at the buried nodes within 6–12 weeks. Once rooted, cut the new plant free from the parent.
Cultivars
'Variegata' / 'Albomarginata'
Heart-shaped leaves with cream-yellow margins around a green centre. The most common variegated form in Nordic trade.
'Reverse Variegata'
Inverse pattern — cream-yellow centres with green margins. Rarer and pricier than the standard variegated form.
'Splash'
Plain green leaves with fine silver speckling, similar to the silver patterning seen in Hoya carnosa 'Splash'. Less commonly available.
'Spotted Leaves'
Older cultivar with random cream/yellow blotches. Sometimes confused with 'Variegata' but the variegation is irregular rather than marginal.
Common problems
Single 'Valentine leaf' never grows
Symptom
A potted single heart-shaped leaf (sold as a 'Valentine cutting') stays alive for months or years but never produces a stem, new leaves, or any growth at all.
Cause
The leaf has no stem node and therefore no growth point ('axillary bud'). Hoya kerrii leaves can root and survive indefinitely on their own stored water, but cannot grow into a vine without a stem section. This is the single most-common houseplant scam — single-leaf cuttings are sold as 'sweetheart hoyas' to consumers who expect them to develop into full plants.
Fix
Nothing will make a no-node leaf grow. The leaf will live for years and is genuinely a charming object, but it is not a developing plant. To get a real Hoya kerrii vine, buy a cutting or plant that includes at least one stem node visible above the soil. Sellers should disclose the difference; reputable garden centres now label single-leaf pots clearly.
Plant never flowers
Symptom
Mature 5+ year-old plant has never produced umbels of flowers.
Cause
Insufficient light is the most common reason. Hoya kerrii needs bright light approaching some direct sun to flower reliably. Other contributors: too much fertiliser nitrogen (push leaf growth at the expense of flowers), over-potting (root system never feels secure), and absence of summer warmth.
Fix
Move to the brightest available spot — east window with morning direct sun, or directly beside a south window with a sheer curtain. Switch to a bloom-formula fertiliser (high-phosphorus, low-nitrogen) from late spring through summer. Allow the plant to be slightly root-bound. Keep summer temperatures consistently warm (22–28 °C). Most Hoya kerrii in average Nordic apartments will not flower without these adjustments.
Sticky drops or black sooty patches on leaves
Symptom
Sticky honeydew drops on leaves; sometimes black sooty patches develop where the honeydew lands.
Cause
If the plant is in flower or post-flower: the dew is plant-produced nectar from spent umbels, which is normal and harmless (just wipe down). If no flowers and the dew is sticky: scale insects or mealybugs producing honeydew. Sooty mould is a secondary infection on the sugary residue.
Fix
Inspect leaf undersides and stem nodes carefully — mealybugs hide as cottony white tufts in node crevices, scale as small brown discs on stems. Treat infestations with rubbing alcohol on a cotton swab (mealybugs) or insecticidal soap (scale). Wipe sooty mould off with a damp cloth. If the dew is from flowers, simply wipe it off — it is just sugar and resolves on its own.
Full guide: Mealybugs on Houseplants: Identification and TreatmentLeaves wrinkling and going soft
Symptom
Thick succulent leaves develop wrinkles or look slightly deflated; petioles become limp.
Cause
Either prolonged underwatering OR root rot from prolonged overwatering — both cause the plant to lose access to water.
Fix
Check the soil and the roots. Dry crumbly soil = underwatered; soak in tepid water for 30 minutes, then resume normal watering schedule. Soggy soil with dark mushy roots = overwatered with rot; unpot, cut away rotted roots, repot in fresh free-draining mix and water sparingly. Wrinkled leaves recover within 1–2 weeks once the underlying water issue is fixed.
Yellow leaves dropping
Symptom
Lower leaves yellow uniformly and drop; occasionally multiple leaves at once.
Cause
Most often overwatering. Some leaf turnover is normal in a mature plant.
Fix
Reduce watering frequency. Allow soil to dry completely between waterings. Inspect roots if symptoms persist. Hoya kerrii is succulent and rotting roots is one of the few ways to kill it.
- Mealybugs (the dominant pest, especially in leaf nodes)
- Spider mites (dry rooms)
- Scale insects
- Aphids (on flower buds)
- Root rot (overwatering)
- Sooty mould on flower nectar
Toxicity & safety
No reported toxicity. The white milky sap can cause mild skin irritation in sensitive individuals — wash hands after pruning.
Hoya kerrii — Plants For A FutureASPCA lists Hoya as non-toxic to cats. No expected oral or systemic effects from chewing.
Wax Plant (Hoya) — ASPCA Toxic and Non-Toxic PlantsASPCA lists Hoya as non-toxic to dogs. No expected oral or systemic effects from chewing.
Wax Plant (Hoya) — ASPCA Toxic and Non-Toxic PlantsThe single-leaf 'Valentine cutting' is one of horticulture's quietest scams. A Hoya kerrii leaf rooted alone (with no stem section above it) will stay alive for years on its own stored water, looking exactly like a healthy plant — but it has no growth point. There is no axillary bud anywhere in a leaf, only in stem nodes. Without a node above the leaf, the plant cannot produce new shoots, ever. Sellers know this and continue to market the single leaves as 'gift plants' for Valentine's Day. The leaves themselves are charming and last for years; they are simply not the start of a growing plant. To grow a real Hoya kerrii vine, the cutting must include at least one stem node.
Frequently asked · 5
Will my single-leaf Hoya kerrii grow into a full plant?+
No, almost certainly not. A Hoya kerrii leaf rooted alone (with no stem section above it) has no growth point — there are no axillary buds in a leaf, only in stem nodes. The leaf will stay alive for years, looking healthy on its own stored water, but cannot produce new shoots. This is the most common Valentine's Day plant scam. To grow a real vine, you need a cutting that includes at least one stem node above the leaf. Single leaves are still charming long-lived objects, just not the start of a growing plant.
Is Hoya kerrii safe for cats and dogs?+
Yes — ASPCA confirms Hoya as non-toxic to cats and dogs. This is one of the few mainstream pet-safe houseplants with a vining habit. Mild stomach upset is possible if a pet eats large quantities of any plant, and the white milky sap can cause minor skin irritation in sensitive individuals — but Hoya kerrii is considered safe for households with chewing cats or dogs.
How often should I water Hoya kerrii?+
When the soil is fully dry — typically every 10–21 days in summer and every 21–35 days in winter. Hoya kerrii is succulent and stores water in its thick leaves; overwatering is the most common cause of death. Water thoroughly until water runs from the drainage holes, then empty the saucer. The leaves go slightly soft and lose their gloss when the plant is genuinely thirsty (a slow gradual change over weeks). Use room-temperature filtered water or rainwater.
Why doesn't my Hoya kerrii flower?+
Three main reasons. (1) The plant is too young — Hoya kerrii typically needs 5+ years before flowering. (2) Insufficient light — flowers require bright light, ideally with some direct sun. (3) Wrong fertiliser — high-nitrogen formulations push leaf growth at the expense of flowers. Move to the brightest spot available, switch to a bloom formula (high-P) in late spring through summer, allow the plant to be slightly pot-bound, and maintain warm summer temperatures (22–28 °C). And critically: NEVER cut off spent flower peduncles — those bumpy stalks left after flowers fade re-bloom annually for years. Cutting them off resets the flowering clock.
How do I propagate Hoya kerrii?+
Stem cuttings that include at least one node. Take a stem section with at least one node and ideally two leaves — a single leaf alone will root but never grow into a plant. Place the cutting in water, sphagnum moss, or a free-draining mix at 22–25 °C with bright indirect light. Roots emerge in 4–10 weeks. Pot up once roots are 3–5 cm long. Layering also works — pin a length of trailing stem against a tray of damp moss with a wire hoop and let nodes root in place. Either method is reliable; both are slow.