Diagnosis and care: brown spots on Mother-in-law's Tongue (Dracaena hyacinthoides)

Identification and symptom

The plant matches Mother-in-law's Tongue (Dracaena hyacinthoides). The main symptom is dark brown spots and discolored areas on lower leaves, while young leaves remain green and healthy. No visible pests are observed. These signs point to localized stress, with a possible onset of rot from moisture at the base or watering damage.

Most likely causes

• Irregular watering or excess moisture at the base that promotes rot in lower leaves.
• Prolonged contact of water on the leaves or watering with very cold water causing tissue damage and spots.
• Potting mix with poor drainage that keeps roots or crown wet and encourages fungal development.
• Physical damage or natural aging of lower leaves, which tend to necrose over time.

What to do now: immediate steps

1. Visual assessment

• Check the pot for signs of bad odor (rot smell) and feel the substrate: if it smells bad or is waterlogged, there is excess moisture.
• Palpate the base of the plant and the roots (if possible): soft or black roots indicate rot.

2. Adjust watering

• Let the top layer of the substrate dry (2–3 cm) before watering again.
• Water with room-temperature water, avoiding very cold water.
• Make sure not to flood the base; moderate, spaced waterings are better than frequent, light ones.

3. Improve drainage and substrate

• Ensure the pot has drainage holes; if it does not, repot into a pot with drainage.
• If the substrate is compacted, loosen the surface or refresh the mix with a loose, well-draining medium (peat-free mix, plus perlite or coarse sand in small proportion).
• Avoid aggressive repotting unless you detect soft roots or bad odor.

4. Prune damaged leaves

• Using clean, disinfected scissors, cut off the very damaged or soft lower leaves.
• Cut as close to the stem as possible without damaging healthy tissue to avoid entry points for pathogens.

5. Environmental conditions

• Place the plant in bright indirect light (the species tolerates medium-high light) avoiding intense direct sun that could scorch the leaves.
• Improve ventilation around the plant to reduce stagnant humidity at the base and on the leaves.
• Avoid wetting the leaves when watering.

Follow-up: observation in 7–14 days

Monitor these points over the next 1–2 weeks:

• The surface of the substrate dries 2–3 cm before the next watering.
• No new spots appear on young leaves.
• No bad odor is coming from the pot.
• New leaves emerge green and firm.

If it worsens

• If more spots appear, roots become soft, or a rot smell develops, consider a deeper repot with fresh substrate and prune affected roots. Use clean tools and reduce watering until the plant recovers.
• If secondary pests are detected (mealybugs, mites), treat according to the pest with potassium soap or a specific insecticide.

Long-term prevention

• Maintain regular but moderate watering, allowing the surface layer to dry between waterings.
• Use a well-draining mix and a pot with good drainage.
• Avoid cold drafts and very cold watering; use room-temperature water.
• Periodically remove very old leaves to reduce moisture accumulation and potential rot sites.

With these care steps, the Mother-in-law's Tongue should stabilize and produce healthy new leaves. Observe the plant and adjust watering and substrate according to its response.