The halberd-leaf rosemallow or Hibiscus laevis produces delicate, showy flowers. These blooms only open in bright sunlight and last for a single day. This deciduous perennial is related to the marshmallow, the plant that was critical to the first marshmallow confections. Its name, meanwhile, references the similarity its leaves bear to the medieval weapon called the halberd.
I. Appearance and Characteristics
Hibiscus laevis (syn. Hibiscus militaris), the halberd-leaf rosemallow, is a herbaceous perennial flower native to central and eastern North America. Their showy, creamy-white or pink flowers are large, up to 15 centimeters (6 in) across, and are hard to miss. These flowers require exposure to sunlight to open up properly, and then last only a single day.
The unbranched stems of this plant are round and hairless, frequently growing to 2 meters (6 ft) tall and sometimes taller. The root system includes a taproot.
The hairless leaves are alternate, 8 to 15 centimeters (3 to 6 in) long, divided into 3–5 pointed lobes (cleft) and have serrate or crenate edges. They are simple and pointed at the tip. The leaves with three lobes resemble a medieval halberd because the middle lobe is much larger than the two side lobes. The five-lobed leaves also look like halberds or daggers.
Flowers are solitary or occur in small clusters at the tops of the upper stems. They are fairly large, about 13 centimeters (5 in) across when fully open. They are mostly white or light pink, but the inside throat of the flower is often maroon or a rich purplish pink color. Each flower has five petals with five hairless green sepals below. There are numerous stamens, all attached to a central column. The pistils have superior ovaries and five stigmas protruding from the central column in the flower. The fruit is an ovoid capsule containing many seeds.
The blooming period can occur from mid-summer to early fall (June to September) and lasts about a month. Each flower lasts only a single day. This plant spreads by reseeding itself. The stalks die down in the winter and grow back in the spring.
This plant prefers full or partial sun and moist conditions. It can grow in sand or clay with sufficient moisture, and can tolerate poor drainage. They are frequently found along streams, ponds and lakes and in marshy areas, roadside ditches, and sometimes in shallow standing water.
The seeds of this plant are eaten by waterfowl and bobwhite quail.
II. How to Grow and Care
Sunlight
Halberd-leaf rosemallow likes ample sunlight for at least six hours a day. However, direct sunlight should be avoided during high temperatures in summer afternoons. Otherwise, the leaves can easily become sunburned.
Temperature
Most Hibiscus plants are relatively resistant to cold, tolerating temperature as low as -18 ℃, and are also relatively resistant to drought. Chinese hibiscus (Hibiscus rosa-sinensis) and its hybridization varieties thrive in warm environments and generally cannot adapt to temperatures below 0 ℃. Temperatures of no less than 10 ℃ are best in winter for most Hibiscus plants. The optimum temperature for Chinese hibiscus is 16 to 32 ℃, and the species is not resistant to drought.
Watering
Thriving in its native moist environments, halberd-leaf rosemallow has adapted to be moderately drought-tolerant while still favoring consistent moisture. It is best suited for watering every week to maintain its hydration balance. As an outdoor plant often found near water bodies, halberd-leaf rosemallow benefit from a growing season that aligns with periods of natural rainfall, enhancing its lush flowering potential.
Soil
Halberd-leaf rosemallow like slightly acidic, moist, well-drained soil with a pH value of 5.5-7. If the soil is sticky and heavy, coarse sands may be added to improve permeability. In the case of slightly alkaline, chalky soil and lime soil, add rotten leaf soil, peat soil, or completely decomposed garden compost along with sulfur fertilizer until the pH value reaches an appropriate range.
Fertilizing
To boost halberd-leaf rosemallow’s growth and bloom quality, utilize balanced nutrition fertilizers. Apply quarterly during growing seasons—spring and summer—with a reduced dose in fall. Establish a lighter regime for winter to avoid over-fertilization. Gradually increase quantity as halberd-leaf rosemallow matures, fostering robustness and flowering. Always water soil before fertilizing to prevent root burn and ensure nutrient absorption. Monitor halberd-leaf rosemallow’s response, adjusting practices for seasonal changes and growth stages, to maintain a thriving, vibrant plant.
Pruning
Halberd-leaf rosemallow generally does not require pruning. If desired, however, it should be pruned in early spring. Keep 2-4 buds on each branch grown the previous year and cut off any dead, diseased, or weak branches. For shrub shaping, trunks should be pruned to different heights, creating a sense of levels. For tree shaping, the lateral branches at the lower trunk should be removed and the upper lateral branches should be shortened.
To restore old branches, prune after blooming in fall. Each trunk should be shortened to a height of 30 to 46 cm. Afterward, apply a slow-release fertilizer. In the next growing season, keep 2-4 stronger, new branches on the trunk.
Propagation
The ideal propagation season for halberd-leaf rosemallow is Spring, with sowing being the preferred method. The propagation process is moderately easy, and successful propagation is indicated by new shoot growth. Ensure proper moisture for optimal success.
Transplanting
The optimal time for relocating halberd-leaf rosemallow is during /’S4-S5/’, it’s late summer to early autumn, when the plant is less active and can better adapt. Choose a sun-kissed location with moist, well-drained soil. Take care not to bury it too deep while transplanting to ensure successful growth.
Overwintering
Halberd-leaf rosemallow heralds from warm-temperate to subtropical climates, naturally tolerating light frost. Its robust root system and hibernating seeds in the soil help to brave the colder periods. For gardeners, winter care is ushered by cutting back the plant, mulching the base for insulation and remembering its resilience; halberd-leaf rosemallow tends to return in spring even after seeming to ‘disappear’ over winter.
Repotting
For halberd-leaf rosemallow, a medium-sized bush, repot every 2-3 years to accommodate growth. Ideal repotting occurs in early spring, aligning with its active growth phase. Choose a container one size larger to ensure ample space for root development. After repotting, maintain consistent moisture and avoid full sun until recovery signs appear, ensuring halberd-leaf rosemallow’s vibrant growth continues.
III. Uses and Benefits
Halberd-leaf rosemallow grows well in moist locations around lakes and ponds, so it’s perfect for water or woodland gardens that contain water features. It has large showy leaves and lovely pink blooms that provide a lot of ornamental value to any garden beds or borders. The flowers appear throughout the summer and fall and draw in pollinators and hummingbirds and, unfortunately, deer.
IV. Harvesting and Storage
The single flower of rose of sharon only blooms for a day and then withers. It is best to pick flowers that have just blossomed at sunrise. The fruit harvest time of Roselle is usually in late fall, one month after blooming. At that point, its sepals are fully developed, turning dark purple before the lower leaves start falling. The fruits can be cut off from the stem base with sharp scissors after the morning dew is dry.
