Question: My pot-grown Jacobean lilies have never flowered in the seven years that I’ve had them. Please enlighten me as to their proper culture.
Answer: The Jacobean lily (Sprekelia formosissima) belongs to the amaryllis farmily (Amaryllidaceae), and when grown indoors requires the same care as the amaryllis (Hippeastrum species). Those that fail to flower most likely are not receiving enough water during active growth or are not being kept cool enough during winter dormancy.
While it’s true that a pot-bound bulb is more likely to bloom, the Jacobean lily ought to be repotted at least every three to four years. January is a good time. Use one four-inch pot per bulb, or combine three bulbs in a six-inch container. Fill it with a standard potting mix lightened with a little sand or perlite, making sure the upper third of each bulb is showing above the soil. Water lightly until new growth appears. When it does, keep the medium moist and apply a liquid houseplant fertilizer (5-10-10 or 5-10-5) once a month. In September, begin withholding water and fertilizer. Once the leaves have died down, let the soil dry out completely before storing the pots in a cool place (45 to 50 degrees Fahrenheit) for the rest of the year. Next January, when signs of new growth begin to appear, move the plants to a windowsill or greenhouse and resume watering. You should be enjoying the Jacobean lily’s spectacular crimson blooms later that spring.