Soil -- Deppea likes moist soil that is high in organic matter, but that also drains well. A good mix would be 2 parts quality potting soil to 1 part perlite or coarse horticultural sand. An alternate mix is equal parts coir fiber and perlite, with some slow-release fertilizer mixed in.
Pot size -- Start your plant in a 1 gallon (4 liter) pot or thereabouts. After a few months, repot to a larger container, like a 3-5 gallon pot (20 liter), or into the ground if you're in a frost-free area. The final pot size is 5 to 20 gallons (20-75 liter), depending on how large you let it grow.
Transplant gently, being careful not to let the soil ball break apart, which can damage the roots. Watering the soil before repotting helps keep the soil together. After transplanting, don't compress the soil down - simply water it. For the first week after transplanting, shade from sun and give no fertilizer.
Climate -- Deppea prefers filtered sunlight. Morning sun + afternoon shade is fine, as well as tree-filtered sunlight all day. It prefers moderate temperatures. The ideal temperatures are between 55 and 85° F (12-29°C) during the day, and 45 to 65° F (7-18°C) at night. In warmer areas, give the plant afternoon shade, and keep the pot shaded to avoid overheating the roots.
You may plant it in the ground in mild-winter areas, such as along the Pacific coast. Protect the plant from all frost. As far as humidity, over about 40% is best.
Watering - Deppea likes evenly moist soil, but it shouldn't be perpetually soggy either. Water whenever the soil is about halfway dry down where the roots are. "Soft" water is preferred, so if your tap water is "hard" (high in minerals), i recommend using bottled water or rainwater, at least until your plant is established.
Feeding - Deppea has average fertilizing needs. Feed about every 2 months with a general-purpose fertilizer that contains micronutrients.
If some of the older leaves turn yellow and drop, this could be a sign that the soil is too dry down in the root zone. If you're certain the roots are moist, it may need more fertilizer (nitrogen).
Deppea can occasionally drop some green, healthy-looking leaves for no apparent reason. This is usually due to a change of some sort - temperature, soil moisture, lighting, repotting, humidity, insects, etc. Once conditions stabilize, the plant will soon sprout new growth.
Pests to watch for - mealybugs, whitefly, aphids, scale, thrips, and spider mites.
If you have any questions, feel free to email me.
Have fun growing it!
Strange Wonderful Things