Identity & taxonomy
- Scientific name
- Mimosa pudica L.
- Family
- Fabaceae
- Genus
- Mimosa
- Order
- Fabales
- IUCN status
- Least Concern (LC)
- Wikidata
- Q148532
- Mimosa pudica var. unijuga (Duchass. & Walp.) Griseb.
- Sensitive planten
- Touch-me-noten
- Shame planten
- Humble planten
- Sleepy planten
- Mimosaen
- Sinnesört / Mimosasv
- Mimose / Sjenert mimoseno
- Mimose / Sippeda
- Tuntoaralia / Mimoosafi
- Mimose / Schamhafte Sinnpflanzede
Tropical South America (Brazil, Bolivia, Paraguay) — now pantropical, naturalised across the tropics worldwide
How to identify it
Growth habit. Low-growing herbaceous sub-shrub with thin wiry stems that sprawl horizontally as the plant ages. Stems are sparsely covered in fine prickles — handle the base with care. Indoors the plant grows fast for one season then becomes leggy and woody; outdoors in tropical climates it forms a low groundcover and is treated as an invasive weed.
Leaves. Bipinnate (twice-compound) leaves 4–10 cm long, each made up of 2–4 main divisions ('pinnae') bearing 12–25 pairs of small oblong leaflets each. The whole leaf collapses dramatically when touched: leaflets fold up in pairs along the central vein within 1–2 seconds, then the entire pinna and leaf petiole droop downward toward the stem. Full recovery (re-opening) takes 5–30 minutes.
Flowers. Spherical pink to lavender 'puffball' inflorescences 10–15 mm across on slender stalks emerging from leaf axils — like tiny powder puffs. Each puffball is composed of 50+ small flowers crowded together, each with long pink stamens that give the puffball its fluffy appearance. Flowering is continuous in summer in good light.
Fruit. Small flat segmented seed pods 1–2 cm long, in clusters of 2–8, that break apart at the joints when ripe. Each pod contains 2–4 hard brown seeds that remain viable for years and germinate readily from a hot-water pre-soak.
- Leaflets fold up in pairs within 1–2 seconds of being touched — the 'sensitive' behaviour is diagnostic.
- Bipinnate fern-like leaves with 12–25 pairs of small leaflets per pinna.
- Pink spherical puffball flowers 10–15 mm across — like tiny powder puffs.
- Wiry sprawling stems with fine prickles along the surface.
- Leaves also fold automatically at sunset (nyctinasty) and reopen at sunrise.
Commonly confused with
Silk tree / 'Mimosa tree'
A large deciduous tree with similar bipinnate fern-like leaves and pink puffball flowers — frequently confused with M. pudica because of the shared common name 'mimosa'. The tree does NOT have touch-sensitive leaves and grows to 10+ m. M. pudica is a small herbaceous plant.
Little tree plant / Life plant
Another touch-sensitive plant in family Oxalidaceae, with a single rosette of pinnate leaves on a slender stem (like a tiny palm). Shares the touch response but is a completely different plant family.
Powder puff tree
A tropical shrub with similar large pink puffball flowers but much bigger (5–7 cm across) and woody simple-pinnate leaves. No touch sensitivity.
Care
Light
Bright direct sun preferred — 4+ hours daily.
Mimosa pudica needs the brightest spot in the home. A south or west window with several hours of direct sun is ideal. In dim conditions the plant becomes spindly, the leaflets become slow to react to touch, and flowering stops. The touch response itself is energy-intensive; plants in low light visibly weaken.
Seasonal: Nordic apartments above ~55°N: supplemental grow lights are usually needed from October through March to keep the plant growing actively. Without them, plants typically die out by midwinter.
Water
Keep evenly moist; never let the soil dry out completely.
Water as soon as the top of the mix feels just dry — typically every 3–5 days in active growth. Mimosa pudica is more drought-sensitive than most houseplants. A single bone-dry spell can kill the plant outright. The soil should be moist but not waterlogged.
Seasonal: Reduce frequency in winter to match the slower growth rate, but never let the soil dry completely.
Soil
Free-draining loamy mix.
Standard peat-free potting soil with extra perlite (3:1) is ideal. As a legume, M. pudica forms nitrogen-fixing root nodules — it does not need rich high-nitrogen mix.
Humidity
50 %+ ideal; tolerates ordinary indoor air.
Mimosa pudica tolerates ordinary indoor humidity (40–60 %) without complaint. It performs better at 50 %+ but does not need humidifier-grade conditions. Misting is unnecessary.
Temperature
18–27 °C; below 15 °C ends the season.
Warm tropical conditions only. Below 15 °C the plant slows dramatically; below 10 °C it usually dies. Keep away from cold draughts and cold windowsills in winter.
Fertilizer
Half-strength balanced feed every 4 weeks during growth.
Feed at half strength every 4 weeks from spring through autumn. The plant is a nitrogen-fixer so heavy nitrogen feeds are unnecessary; a balanced or low-nitrogen feed gives the best flowering.
Pruning
Pinch back stems to encourage bushiness; treat as an annual most years.
Pinch the tips of new stems regularly to promote branching and prevent legginess. Even with good care, indoor plants typically decline after 12–18 months and are easier to restart from seed than to nurse through a second year.
Repotting
Once a year if kept; usually replaced from seed annually.
If the plant survives into its second season, repot once a year in spring into a slightly larger pot with fresh mix. Most growers find it easier to collect seed and start over each spring — seedlings grow fast and bloom within 3–4 months.
Seed (the standard method)
easy~Germination in 7–14 days; flowering in 12–16 weeksThe standard and most reliable method. Soak seeds in hot (not boiling) water for 24 hours before sowing — the seed coat is hard and germination is unreliable without scarification. Sow on damp seed mix, cover with 5 mm of mix, and keep at 22–27 °C. Seedlings emerge in 7–14 days; first leaves show the touch response within 4–6 weeks. The plant flowers in 12–16 weeks from sowing.
Cuttings
moderate~3–5 weeksPossible but unreliable. Take 5–10 cm tip cuttings, dip in rooting hormone, and pot up in damp seed mix under a humidity dome. Many cuttings fail; seed is faster and more reliable.
Common problems
Leaves don't reopen after closing
Symptom
Leaves fold shut and stay folded for hours or overnight; some never reopen.
Cause
Either temporary stress (touch response, sunset closure — both normal) or permanent stress (severe underwatering, cold, root damage).
Fix
If the plant has been touched recently, wait 30 minutes — leaves should reopen. If not reopening by midday, check soil moisture and temperature. Cold-stressed or rootbound plants react slowly.
Plant becomes leggy and woody after a few months
Symptom
Stems elongate, lower leaves drop, plant looks scraggly and over-the-hill.
Cause
Natural decline — Mimosa pudica is short-lived indoors.
Fix
Pinch back regularly to encourage branching, but accept that indoor plants typically last only 12–18 months. Collect seed pods before the plant dies and start fresh in spring — seed-grown plants are the standard approach to keeping this species year-round.
Touch response weakens or disappears
Symptom
New leaves close slowly or not at all when touched.
Cause
Insufficient light or dehydration — the touch response is energy-intensive.
Fix
Move to a brighter spot (full direct sun for several hours daily) and ensure the soil never dries out. Touch response typically strengthens within 1–2 weeks of better light.
Whole plant collapses overnight
Symptom
Healthy-looking plant goes limp suddenly, often in winter.
Cause
Cold stress (below 10 °C) or root rot from soggy soil.
Fix
Check temperature first; move away from cold windows. If the soil is sodden, lift the plant and check roots — a soft root ball means rot, and the plant is unlikely to recover. Restart from seed in spring.
- Spider mites in dry conditions
- Whitefly on flowers
- Aphids on new growth
- Damping-off in seedlings if overwatered
- Powdery mildew in still air
- Root rot in soggy mix
Toxicity & safety
Mimosine — a non-protein amino acid — is present in seeds and leaves and causes hair loss and growth depression in livestock that graze on the plant in quantity. Human ingestion of the small amounts present in a houseplant is unlikely to cause harm but is best avoided. The fine stem prickles can cause skin scratches.
Mechanism: Mimosine (a non-protein amino acid).
Mimosa pudica — North Carolina State Extension Toxic PlantsNot separately listed by ASPCA, but mimosine is known to cause hair loss and GI signs in mammals that consume the plant in quantity. Keep out of reach. Contact a veterinarian if a cat eats more than a leaf or two.
Mechanism: Mimosine.
Mimosa pudica — North Carolina State Extension Toxic PlantsNot separately listed by ASPCA, but mimosine causes GI signs and possible hair loss with sustained ingestion in livestock. Keep out of reach. Contact a veterinarian if a dog ingests more than a leaf or two.
Mechanism: Mimosine.
Mimosa pudica — North Carolina State Extension Toxic PlantsWhy the leaves fold when you touch them — the science of thigmonasty
The touch response of Mimosa pudica is one of the fastest movements in the plant kingdom. When a leaflet is touched, electrical signals propagate from the touched cell along the leaf at roughly 2–3 cm per second. The signals reach specialised motor cells (pulvini) at the base of each leaflet pair and trigger a sudden loss of turgor pressure on one side of the pulvinus. Water moves rapidly out of those cells; the pulvinus collapses; and the leaflet folds shut. The whole sequence takes 1–2 seconds.
Recovery is slow. Water has to be pumped back into the pulvinar cells against an osmotic gradient — a metabolically expensive process. Re-opening takes 5–30 minutes depending on light, temperature, and how vigorously the plant was disturbed. The leaves also fold automatically at sunset (nyctinasty) and reopen at sunrise; the same cellular machinery handles both responses.
The function of thigmonasty is uncertain. The leading hypothesis is anti-herbivory — the sudden collapse startles small insect grazers and exposes the prickly underlying stems. Recent work suggests it may also reduce wind damage and water loss in heavy rain. Either way, it makes the plant the world's most reliable demonstration that plants are far from passive.
Mimosa pudica was the subject of one of the earliest published experiments demonstrating plant 'memory': in 2014, biologist Monica Gagliano showed that plants repeatedly dropped onto a soft surface eventually stopped folding their leaves in response — a habituation that persisted for at least 4 weeks. The result is contested but remains the most-cited modern paper on plant cognition. Whether the plant 'remembers' or simply runs down a metabolic budget is still debated.
Frequently asked · 5
Is the sensitive plant safe for cats and dogs?+
Mimosa pudica is mildly toxic — its seeds and leaves contain mimosine, a non-protein amino acid that causes GI upset and possible hair loss in mammals consuming the plant in quantity. Keep out of reach of pets and small children. Contact a veterinarian if a pet eats more than a leaf or two.
Why don't my sensitive plant's leaves close anymore?+
Either insufficient light or dehydration. The touch response is energy-intensive — plants in dim rooms or with dry soil stop reacting. Move to a bright direct-sun window and water more consistently; the response usually returns within 1–2 weeks.
How long does a sensitive plant live indoors?+
Typically 12–18 months. Mimosa pudica is short-lived as a houseplant — even with good care, plants become leggy and decline after one season. The standard approach is to collect seed pods before the plant dies and restart from seed each spring; seedlings flower within 12–16 weeks.
How do I grow a sensitive plant from seed?+
Soak seeds in hot (not boiling) water for 24 hours to soften the hard seed coat — germination is unreliable without this step. Sow on damp seed mix, cover with 5 mm of mix, and keep at 22–27 °C. Seedlings emerge in 7–14 days; first touch responses develop in 4–6 weeks; flowering at 12–16 weeks.
Can I keep a sensitive plant outside?+
In tropical climates, no — the species is a serious agricultural weed, and bringing a houseplant outside risks contributing to its naturalisation. In cool temperate climates (the UK, Scandinavia, most of Europe) it cannot survive winter outdoors, so brief summer holidays on a balcony are fine and harmless. Bring it back inside before nights drop below 15 °C.
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