Dracaena are commonly grown houseplants. They require warm semitropical conditions that are usually only found indoors or in a green house. Dracaena marginata is also known as Madagascar dragon tree or red dragon tree and is suitable for outdoor growing in U.S. Department of Agriculture hardiness zones 10 to 12. The plant may get up to 20 feet in its native region, but as a houseplant it will get only about 6 feet tall. As with all houseplants, some pest and cultural problems may exist.
Chlorosis is a symptom of yellow bands on the leaves or even necrotic spots. It may be caused by periods of excess chilling such as when the plant is shipped or a potted plant is not moved indoors when temperatures drop. It is also a symptom of a deficiency, often iron, or of a toxicity. The toxicity is from excess salts or minerals building up in the soil. Usually this occurs in a potted plant that has been overly fertilised. Salts, boron and fluoride are common toxicities. They can be cleared by flooding soils and avoiding the use of tap water.
Dracaena marginata is native to a region where there are torrential rainy seasons and periods of drought. It can withstand long periods without water but excess water can cause root rot, yellowing leaves and foliar problems. The best growing medium is peat and bark, which provides superior drainage. Complete irrigation followed by complete drying out is the best watering plan for the plant. Dracaena marginata should be grown in full to partial sun. Low light locations will severely affect the vigour of the plant and cause the leaves to lose chlorophyll and bleach out.
The tree is not prone to many pests but two of the most common, mealybugs and scale, are often found on the plant. Mealybugs and scale are called sucking insects because they suck the sap from plants. They may be found on the leaves, stems or trunk of the dracaena. Scale are soft or hard armoured tiny insects. They typically just look like a bump on the flesh of the plant and can be scraped off with a fingernail. Mealybugs are white, fuzzy insects that are very difficult to get rid of. Both insects produce honeydew which may cause sooty mould, a black fungal disease, on the leaves. Use hard sprays of water or an insecticidal soap to combat the pests.
Dracaena marginata may be plagued by cosmetic issues such as flecking of the foliage. The plant may get yellow to white spots on the leaves. This is a response from the stoma to environmental pollution or toxins and low light conditions. The dracaena may also weep, which is called guttation. The weeping comes from special cells that produce excess moisture mixed with salts and sugars. It collects on the tips of the leaves and can make them turn brown.