Greetings, Gardener. We are Polianthes tuberosa, a species known for our intoxicating fragrance and elegant white blossoms. To thrive in your American garden, we require specific conditions that mimic our native warm habitats. Here is what we need from you.
We are tender perennials, originating from warm regions. We thrive in USDA Hardiness Zones 7 through 10. In these zones, you can plant our tuberous rhizomes (often called bulbs) directly in the ground after the last spring frost, when the soil has warmed significantly. In cooler zones (6 and below), you must treat us as annuals or lift us for winter storage, as we cannot survive freezing temperatures. We demand a location that receives full, glorious sun for at least 6 to 8 hours daily. Without it, our stems will become weak and our flowering will be poor.
Our roots despise waterlogged conditions. Therefore, the soil you provide must be very well-draining. A sandy loam amended with organic compost is ideal. This provides both drainage and the nutrients we crave. The soil pH should be slightly acidic to neutral (6.0 to 7.0). Before planting, work a balanced, slow-release fertilizer into the soil. Plant our rhizomes about 2 to 3 inches deep and 6 to 8 inches apart, with the growing tip (often looks like a small spike) pointing upward.
Water us deeply immediately after planting to settle the soil around our roots. As we begin to grow, maintain consistent moisture, but never allow the soil to become soggy. A good rule is to water when the top inch of soil feels dry. Once our flower spikes emerge and throughout our blooming period, our water needs increase. After flowering, you can gradually reduce watering. For nutrition, a monthly application of a balanced liquid fertilizer or a fertilizer higher in phosphorus (the middle number) will encourage our spectacular blooms.
We are late bloomers, typically flowering from mid-summer into fall. Our fragrant flower spikes can reach 2 to 3 feet tall. After we have finished blooming, allow our foliage to remain. This is crucial. We need to photosynthesize and gather energy to store in our rhizomes for next season's growth. Once the leaves yellow and die back naturally, you can cut the foliage to the ground.
In zones 7 and warmer, a thick layer of mulch may be sufficient to protect our rhizomes over winter. In colder zones, you must dig us up before the first hard frost. Gently brush off the soil, let our rhizomes dry in a warm, airy place for a week, and then store us in a box filled with peat moss or dry sand. Keep us in a cool (50-60°F), dark, and dry place until it is time to replant us in the spring.
