Moonflower's lush heart-shaped leaves and climbing ways add vertical interest to borders by gracefully twining up trellises and arbors. Northern gardeners in short-season areas should start moonflower seeds indoors, enabling them to gain a head start on the growing season. Once the nights become warm, transplant them into containers. Soil and water on the lean side and constricting root run in containers will promote flowering, as will an application of flower fertilizer in mid and late summer. Avoid nitrogen fertilizers that promote leaf growth over flowering. The blooming period for moonflowers typically begins in late summer and extends into early fall, lasting until the arrival of frost. The tightly furled buds of moonflowers unfurl rapidly, revealing their full beauty and sending forth a potent fragrance that diminishes as they become pollinated. Warm and humid summer evenings enhance this enchanting scent. Caution: seeds contain some toxic alkaloids.