What can you enjoy in your winter greenhouse that requires little care the rest of the year? In a recent conversation with Scott Canning, Director of Horticulture at Wave Hill– the public garden in Riverdale, New York– I learned about some South African winter-blooming bulbs growing in Wave Hill’s conservatory this winter. Since South African winters are bright and cool, just not nearly as cold as ours, these bulbs don’t need actual “forcing.” An approximation of their natural growing habitat– easily provided in this hemisphere by the winter greenhouse—is all they require to be coaxed into bloom.
With a preference for night temperatures around 50°F and daytime highs of 65°, they make perfect container subjects, thriving in the same conditions as Cineraria and Cyclamen. Lachenalia hybrids, including L. ‘Rupert’ and L. ‘Romaud,’ are available from Brent and Becky’s Bulbs and bloom for more than six weeks. Moreas are in the iris family, and have flowers and leaves reminiscent of them. The flowers of M. aristata have white petals with dramatic blue patches on them. Mr. Canning finds Moreas particularly rewarding and says they’re not difficult to grow. The blossoms of Scilla peruviana form striking spheres composed of numerous deep violet flowers. He points out that despite their name, these are not from Peru, and finds them remarkably shade-tolerant.
The bulbs are stored in pots beneath the greenhouse benches at Wave Hill the rest of the year; Mr. Canning suggests a basement would work well too. When nighttime temperatures begin to drop around October 1st, the pots are moved into the light, kept around 50° and watered. Cooler temps, especially at night, are fine, but higher ones can be problematic, particularly when above 70°.
Many South African bulbs can also be started from seed. The process isn’t difficult, but does require patience–most take at least three years to reach blooming size. The first year they send up grassy leaves, and in the second season they produce tiny bulbs.
Mr. Canning recommends planting in standard terracotta pots, which provide better drainage than bulb pans. The Wave Hill soil mix is a 50/50 mix of builder’s sand and sifted compost. Bone meal can be added for nutrients, with an additional dose of diluted fertilizer when buds are setting.
Their bloom will peak in Wave Hill’s conservatory between January and March–if you’re in the neighborhood, you should definitely stop by for a visit.