Miru, commonly known as the Four O’Clock flower or Marvel of Peru, is an easy-to-grow plant. It is known for its unique flowering habit, thriving with minimal effort and making it a favorite for both experienced gardeners and newcomers. Its daily display provides beauty and fragrance in the evening when many other flowers have closed for the day.
Understanding the Miru Plant
The Miru plant (Mirabilis jalapa) is a bushy, tender perennial. It typically grows 2 to 3 feet tall and spreads similarly, featuring slightly pointed oval leaves on multi-branched stems. The trumpet-shaped flowers come in a wide array of colors including white, yellow, pink, magenta, and red. They can even display multiple colors or unique patterns like marbling and stripes on a single plant.
The common name “Four O’Clock” comes from its daily blooming cycle; the fragrant flowers typically open in the late afternoon, around 4 p.m., and remain open throughout the evening until the following morning. This nocturnal blooming habit releases a sweet, often lemon-like fragrance that can fill the evening air, attracting pollinators such as hummingbirds and moths. Miru plants have elongated, dark-colored, tuberous roots, resembling large carrots, which allow them to persist as perennials in warmer climates (USDA Zones 7-11).
Growing Miru Plants
Miru plants grow best in locations that receive full sun, meaning at least six hours of direct sunlight daily, though they can tolerate partial shade, especially in hotter climates. Well-draining soil is important for these plants, with a preference for rich, loamy conditions and a neutral to slightly acidic pH. While adaptable to various soil types, good drainage helps prevent root rot.
Consistent moisture is beneficial for Miru plants, particularly during their establishment phase. Water the plants when the top 1 to 2 inches of soil feel dry, but avoid overwatering. Adding a layer of mulch around the base of the plants helps retain soil moisture. Miru plants are tender perennials that do not tolerate temperatures below 30°F. For planting, seeds can be sown directly in the garden after the last frost has passed, or started indoors six to eight weeks before the projected last frost date. Soaking the seeds overnight in water improves germination rates. If planting tubers, ensure the danger of frost has passed before placing them in the ground.
Care and Maintenance
Miru plants are generally straightforward to care for. Fertilizing needs are minimal; if your soil is rich, a yearly application might suffice, but in less fertile soils, a balanced fertilizer can be applied monthly during the growing season. Avoiding excessive fertilization is important, as these plants tend to thrive in average to poor soil conditions.
Pruning mainly involves deadheading spent blooms, which can encourage the plant to produce more flowers. While not strictly necessary for continuous blooming, it can also help manage self-seeding if you wish to limit the plant’s spread. Pinching back the main shoot of young plants can promote a bushier growth habit. Miru plants are generally resistant to most pests and diseases, though issues like aphids, rusts, and leaf spot can occasionally occur. In colder climates (USDA Zones 6 and below), the tuberous roots can be dug up after the first light frost in autumn, dried, and stored in a cool, dry, non-freezing location over winter, to be replanted in spring.
Propagating Miru Plants
Miru plants can be propagated through two methods: collecting and sowing seeds, or dividing their tuberous roots. For seed propagation, collect the dark, pea-sized seeds from faded blooms in late summer or early fall. Allow these seeds to dry for several days in a cool location before storing them in an envelope in a cool, dry place until the following spring. Soaking the seeds overnight in water enhances germination.
Dividing tubers is another effective propagation method, particularly for established plants. This can be done in the spring before new growth begins, or when digging up tubers for overwintering. Identify bulbous growth buds or “eyes” on the tuber, then carefully cut the tuber into sections, ensuring each section has a piece of the original stem and at least one eye. Replant the divided tubers immediately to minimize stress and encourage new growth.