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Coleus comosus
Caution🐾Verpiss-dich-Pflanze · (Plectranthus caninus)
Mint family (Lamiaceae)
Description
This ornamental relative of the coleus genus (Lamiaceae) became known in 2001 under the brand name 'Piss-off plant', introduced by a nurseryman in southern Germany with the promise that its scent, released on touch, would stop cats and dogs from marking the garden. That repellent claim is insufficiently supported scientifically — no controlled studies exist, and German consumer-protection bodies have repeatedly called the marketing misleading. Botanically, the plant is considered a horticultural hybrid of uncertain parentage originating in southern and eastern Africa. Its glandular-hairy leaves release an intense, camphor-and-mint-like scent when crushed, which many people find unpleasant. Unlike related species such as the forskolin-yielding coleus, Plectranthus caninus has no documented medicinal use and should be regarded purely as an ornamental. It is not frost-hardy, and in sensitive skin or with a known mint-family allergy the crushed sap may cause irritation.
External use only!
This plant must NOT be taken internally. Use only as compress, salve, or bath.
Plectranthus caninus is grown as a low, spreading ground cover and bedding plant in part shade or sun. The succulent-like, slightly hairy leaves and compact habit suit rock gardens, containers and seasonal stepping-stone plantings in Mediterranean borders. The inconspicuous blue-violet labiate flowers appear in late summer and attract pollinators. As a hybrid of disputed genealogy, the plant is grown in central Europe only as an annual or container subject — it is not frost-hardy.
Marketing myth and commercial history: the plant was introduced in 2001 by the Swabian nurseryman Dieter Stegmeier (Essingen) under the brand name 'Verpiss-dich-Pflanze' (literally 'Piss-off plant'), claiming that its scent — released when touched — deters cats and dogs from marking in the garden. The claimed repellent effect on pets is INSUFFICIENTLY supported scientifically: no controlled studies with randomised animal samples exist, only anecdotal reports with mixed outcomes — some animals react, many ignore the plant. German consumer protection bodies (Stiftung Warentest, Verbraucherzentralen) and horticultural press have repeatedly classified the advertising claims as misleading or inadequately substantiated. The plant therefore remains a historically interesting ethnobotanical example of commercial folklore, not an evidence-based animal-repellent measure.
When touched or crushed, the glandular-hairy leaves release a strongly musky-mentholic scent reminiscent of camphor and mint — typical of essential-oil-bearing Lamiaceae. Many people find the smell unpleasant to acrid. As an aromatic plant it can be placed along paths or near seating as a 'touch-fragrance' plant, but its intense scent makes it less suitable directly at dining or seating areas.
Taxonomic placement and origin: Plectranthus caninus is presumed to be a horticultural hybrid whose exact parent species are disputed. The literature repeatedly equates it with Plectranthus ornatus (= Coleus comosus) or treats it as a selection thereof. The underlying wild species originate in southern and eastern Africa (Coleus complex). Within the genus Plectranthus, the 'Piss-off plant' is therefore an ornamental without documented traditional medicinal use — a clear contrast to related species such as Plectranthus barbatus (a source of forskolin) or Plectranthus amboinicus (a culinary herb).
Caution note (not a therapeutic indication): in sensitive individuals, prolonged direct skin contact with crushed plant sap may cause transient irritation, redness or mild burning. True contact dermatitis from Lamiaceae is rare but possible with known mint-family allergy (rosemary, sage, mint). Garden gloves are recommended when cutting back or repotting larger stands — this is an ethnobotanical caution, not a medicinal use.
⚠ External use only
Plectranthus caninus is commercially marketed as the 'Piss-off plant' against marking by cats and dogs — this repellent claim is INSUFFICIENTLY supported scientifically and should not be relied upon as a reliable animal-deterrent measure. On touch it releases a strong, musky-mentholic scent that can be unpleasant for people with a sensitive nose. Sensitive skin types may rarely experience irritation from plant sap (Lamiaceae allergy). The plant is NOT edible and has NO documented traditional or clinical medicinal use — it is purely ornamental. ASPCA classification (accessed 2026-08-10): toxic to dogs, cats and horses.
No data on internal use during pregnancy — Plectranthus caninus is not a medicinal or culinary plant. Wear gloves when handling larger stands; no specific precaution otherwise.
No data — no medicinal use. Mere presence near the plant is not a concern.
Small children should not put leaves in the mouth — the intense aromatic flavour and possible gastric irritation from essential oil argue against oral ingestion. No serious poisonings are documented, but the plant is not intended for consumption. After accidental ingestion, provide plenty of water and observe; contact a poison control centre if symptoms persist.
Contraindications
- Known hypersensitivity to mint-family plants (Lamiaceae) such as rosemary, sage, mint or lavender — cross-reactions possible.
- Any internal use — Plectranthus caninus is not a medicinal plant; no documented traditional use, no pharmacological data.
- Reliance on the advertised repellent effect against cats or dogs in sensitive plantings — efficacy is insufficiently substantiated; complementary measures (fences, granular repellents) are advisable.
- Outdoor planting before the last spring frosts — the plant is not frost-hardy and loses leaves even with light night frosts.
- Direct skin application of crushed sap on inflamed or open skin — no efficacy data, possible irritation.
Harvested part: leaves (scent)
- Time of day:
- For maximum scent release on touch (if fresh leaves are wanted for repellent trials), harvest in late morning during dry, sunny weather — essential-oil content in the glandular hairs peaks then. For cuttings for propagation, cut in the morning or late afternoon to minimise wilting stress.
- Drying:
- Plectranthus caninus is NOT dried in practice — it is not a 'drug plant'. Dried leaves rapidly lose their characteristic scent and have no documented use. Fresh leaves can at most be lightly shade-dried for short scent samples or plant identification.
- Storage:
- 1 months — Keep fresh leaves or cuttings at room temperature in a glass of water for at most a few days. Longer storage is not meaningful — the plant is used alive, not dried.
- Time of day:
- Propagation by cuttings (main method): in late spring or early autumn, after the last spring frosts or before the first autumn frosts. Cut 8-10 cm shoot tips during the day in mild weather, remove lower leaves and place in moist seed compost or a glass of water. Roots form within 2-3 weeks.
- Drying:
- Not applicable — propagation material is used live and immediately potted up or planted out.
- Ätherisches Öl (alpha-Pinen, beta-Pinen, Sabinen, Limonen, Carvon)Essential oilContent: 0.1-0.5 %Leaf
Complex monoterpene mixture in the glandular trichomes of the leaf surface. Composition varies considerably by chemotype and growing conditions; pinenes, sabinene and carvone are typical odour-defining components for the genus Plectranthus. Released on touch — main cause of the characteristic musky-mentholic scent.
- Diterpene (Coleon-Typ Abietane)OtherLeaf
Abietane diterpenes have been described in many Plectranthus and Coleus species (coleon family). They are inadequately characterised in P. caninus itself but are typical of the genus. Unlike P. barbatus, where forskolin (a labdane diterpene) is the dominant pharmacological principle, P. caninus has NO confirmed pharmacologically active diterpene markers.
- RosmarinsäurePhenolic acidContent: 0.2-1 %Leaf
The leading phenolic acid of virtually all Lamiaceae; present in moderate amounts in Plectranthus leaves. Water-soluble, mildly antioxidant and anti-inflammatory. Contributes to the antimicrobial baseline of the leaves but has no specifically documented therapeutic role in P. caninus.
- Flavonoide (Apigenin- und Luteolin-Glykoside)FlavonoidLeaf
Flavones and flavone glycosides as typical Lamiaceae secondary metabolites. Present in trace to moderate amounts in Plectranthus species; contribute to baseline antioxidant capacity. Not quantified in P. caninus and without documented pharmacological relevance.
- Phenolsäuren (Kaffeesäure, Chlorogensäure)Phenolic acidLeaf
Companion phenolic acids alongside rosmarinic acid; widely distributed in Lamiaceae. They are part of the plant's pathogen defence and contribute to taste and aroma. No specific application in P. caninus.
- Gerbstoffe (Lamiaceen-Tannine)TanninLeaf
Astringent tannins in small amounts, typical of Lamiaceae leaves. They contribute to the slightly puckering note of the leaf taste. No therapeutic use documented in P. caninus.
- Triterpensäuren (Ursolsäure, Oleanolsäure)OtherLeaf
Pentacyclic triterpenes as Lamiaceae companion substances in the leaf surface wax. They contribute to leaf hydrophobicity and pathogen resistance. Not specifically quantified in P. caninus; no documented therapeutic effect.
- [3]MonographColeus caninus Roth — Plants of the World Online (Royal Botanic Gardens Kew)(accessed: 2026-05-27)
- [5]MonographVerbraucherzentrale / Stiftung Warentest — Bewertung kommerzieller Katzen- und Hundeabwehrmittel inklusive 'Verpiss-dich-Pflanze'(accessed: 2026-05-27)
- [6]MonographNDR Markt / Mein schöner Garten — Verpiss-dich-Pflanze: Wirkung umstritten(accessed: 2026-05-27)
- [7]MonographBaumschule Horstmann — Plectranthus caninus 'Verpiss-dich-Pflanze' Pflanz- und Pflegeanleitung(accessed: 2026-05-27)
- [8]MonographASPCA Animal Poison Control — Coleus (Coleus ampoinicus): Toxic to Dogs, Toxic to Cats, Toxic to Horses(accessed: 2026-08-10)
- [1]WikipediaVerpiss-dich-Pflanze (Wikipedia DE)(accessed: 2026-05-27)
- [2]WikipediaColeus caninus (Wikipedia EN)(accessed: 2026-05-27)
- [4]WikidataPlectranthus caninus / Coleus caninus (Wikidata)(accessed: 2026-05-27)
Distribution in Europe
🪴 Grow at home
- ☀ Light
- full sun
- 💧 Water
- every few days
- 🌱 Soil
- Standard compost with drainage
- 🪴 Pot
- 20 cm
- ⭐ Difficulty
- ★☆☆ beginner
- 🐾 Pets
- toxic to pets
Tips:
- Smell only triggers on contact — place where cats walk past.
- Not frost-hardy — bring inside or treat as annual.
- Repellent effect on cats/dogs scientifically debated.
Care tips are general indoor-gardening recommendations, not scientific sources.