Plant care guide
Snake Plant Brown Spots: Fungal Leaf Spot or Something Else?
Updated
Why does my Snake plant have brown spots?
Brown spots on a snake plant are more often sun scorch, cold damage or rot from wet mix than a fungus. True fungal leaf spot does occur: Fusarium leaf spot starts as tiny water-soaked dots on young leaves kept wet, and anthracnose makes spreading water-soaked patches that later show black dots in rings.
What to do first
Press the spotted leaf and check the mix. Soft, wet tissue near the base points to rot, so check the roots. Dry, papery patches on the window side point to sun or cold. If spots start water-soaked and keep spreading, cut off affected leaves with clean tools and keep the leaves and the centre of the plant dry.
Brown spots stand out on a snake plant because its leaves normally stay clean for years. The RHS sansevieria growing guide describes these plants as generally disease-resistant. So a spot is worth reading carefully before you reach for a fungicide.
Most brown spots on indoor snake plants come from sun, cold or wet roots. Fungal leaf spot is real, but it needs wet leaves to get going.
Read the spot
| What you see | Likely cause |
|---|---|
| Dry, pale or papery patch on the side facing the window | Sun scorch |
| Collapsed or dark patches after a cold window, draught or journey | Cold injury |
| Soft, brown or translucent tissue near the soil, mix wet | Rot from overwatering |
| Tiny water-soaked dots on young leaves that enlarge and turn reddish | Fusarium leaf spot |
| Water-soaked patches that spread across the leaf, then black dots in rings | Anthracnose |
| Corky, raised bumps on the leaf surface | Edema |
| Fine pale speckling with dark specks, or brown bumps that scrape off | Thrips or scale insects |
Sun scorch. The RHS advises keeping snake plants out of midday summer sun, which can scorch the leaves. Penn State Extension’s snake plant article also warns direct sun can burn it.
Cold. The RHS gives 15–24 °C (60–75 °F) as the ideal range and says to keep plants out of cold draughts. NC State Extension’s snake plant profile says it tolerates cool temperatures around 10 °C (50 °F), not cold glass in winter.
Rot. NC State warns that overwatered roots rot. Penn State calls root rot a common affliction of snake plants. Browning that starts at a soft leaf base is a root-zone problem, not a leaf spot.
Fusarium leaf spot. A Connecticut extension horticulturist’s paper on foliage plant diseases, hosted by NC State, lists Sansevieria as a host. Spots begin as pinpoint, water-soaked dots that enlarge and take on a reddish colour. Infection starts in the young growing point, helped by water that collects there.
Anthracnose. University of Florida IFAS researchers described anthracnose on snake plant cultivars ‘Laurentii’ and ‘Moonshine’. Small water-soaked lesions expand across the width of the leaf. Black fungal structures then form in concentric rings.
Edema. University of Maryland Extension’s edema page names snake plant among susceptible plants. It happens when roots take up more water than the leaves lose. The bumps can turn brown and look like disease.
Pests. NC State lists banded greenhouse thrips, fern scale and mealybugs on snake plant. Brown bumps that flake off under a fingernail are insects, not spots.
What to do
- Press the spotted leaf and check the mix. If the base is soft or the mix is wet, stop watering and follow our snake plant root rot guide.
- Move a scorched or chilled plant. Pull it back from midday sun or away from cold glass and draughts.
- For water-soaked, spreading spots, remove the leaf. The UF researchers recommend removing and discarding diseased leaves, pruning only when the plant is dry, and disinfecting tools. Cut at soil level, as Penn State suggests, and wear gloves: the RHS says the sap irritates skin.
- Keep the leaves dry. Water the mix, not the rosette, so water does not sit in the growing point. Penn State Extension’s Ficus disease guide makes the general point: indoor air is too dry for leaf diseases to spread unless watering wets the leaves.
- Consider a fungicide only if new spots keep appearing. Clemson Extension’s disorders factsheet describes fungal leaf spots as small brown spots with yellowish margins. It advises removing infected material first and lists copper soap and chlorothalonil among the options. Follow the product label.
Judge it by new leaves
A brown spot will not turn green again. Recovery means no new spots on fresh leaves. If spots keep spreading after the leaves are kept dry, a local extension plant diagnostic lab can confirm the cause.
Spots only at the tips are covered in our snake plant brown tips guide. Yellowing leaves have their own checks in our yellow leaves guide. For fungal versus bacterial spots on other plants, see leaf spot diseases on houseplants.
References
- NC State Extension Gardener Plant Toolbox: Dracaena trifasciata
- RHS: How to grow sansevierias
- Campoverde and Palmateer, University of Florida IFAS: Colletotrichum sansevieriae Causing Anthracnose of Sansevieria trifasciata (Proc. Fla. State Hort. Soc. 2012)
- Judd, R. W.: Diseases of Foliage Plants (NC State Extension HortScans)
- Clemson Cooperative Extension, HGIC 2251: Houseplant Diseases & Disorders
- Penn State Extension: Snake Plant, A Forgiving, Low-maintenance Houseplant
- Penn State Extension: Ficus Diseases
- University of Maryland Extension: Edema of Indoor Plants
How this guide was put together: NC State Extension, RHS, University of Florida IFAS, Clemson Extension, Penn State Extension and University of Maryland Extension guidance.