What’s the problem – is it rust?
My 10-year-old dragon tree has been happily growing in a bright attic room, but recently the leaves have developed brown splotches.
Diagnosis
It’s unlikely to be rust (a fungal infection). Dragon trees (Dracaena marginata) are not particularly prone to rust infections – the splotches are more likely caused by under-watering, tap water or dry air from being too close to a heat source. Dracaenas are very sensitive to salts, minerals, and chemicals, such as fluoride and chloride, which can lead to leaf discoloration.
Prescription
Start by checking your watering routine. Let the top 5-8cm of soil dry out before watering, and ensure the pot has adequate drainage to avoid waterlogging. If you’re using tap water, switch to filtered water or leave tap water to sit overnight, to allow chemicals to dissipate. Increase humidity around the plant by misting it occasionally, using a pebble tray, or placing a humidifier nearby. And move away from radiators or heaters. Prune off any severely affected leaves to redirect energy to healthy growth.
Prevention
Keep the plant in a bright, indirect light position and water weekly with filtered water. Feed it with a diluted houseplant fertiliser during spring and summer.
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