Rose of sharon ‘Red Heart’ is a Hibiscus shrub that produces white flowers with red centers (or ‘hearts’). Plant the Red Heart in groupings of three shrubs in areas around your yard for bright color from mid summer to fall frost. Groupings of three plants are visually appealing as backdrops or anchor plants in corners of the landscape.
I. Appearance and Characteristics
Red Heart Rose of Sharon is a large multi-stemmed shrub. The tropical-looking blooms on this flower are beautifully pure white with rich red centers. This unique flower will bring pollinators and rarely see visits from deer. The strong stems make for a wonderful flowering hedge in the landscape. You can expect this display to start around mid-July and end around fall. Keep this shrub mulched to retain hardiness during the winter months. Companion plants are lilac, forsythia, viburnum, and hydrangea.
II. How to Grow and Care
Sunlight
Rose of sharon ‘Red Heart’ 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
Originating from East Asia, rose of sharon ‘Red Heart’ thrives in a well-drained environment with consistent moisture, similar to its native habitat’s balanced humidity levels. This species exhibits moderate drought tolerance and prefers a stable watering routine, necessitating hydration once every three weeks. As an outdoor plant that flourishes in full sun to partial shade, rose of sharon ‘Red Heart’ benefits significantly from mulching to retain soil moisture during dry spells. The optimal growth of rose of sharon ‘Red Heart’ is closely tied to regular watering schedules that support its deciduous nature, ensuring vibrant blooms throughout the growing season.
Soil
Rose of sharon ‘Red Heart’ 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
Adult plants do not require frequent fertilization, but flowering plants are best fertilized annually. In early spring, granular or powdery slow-release fertilizer should be mixed into the soil around the aboveground part of the plant, generally 60-70g/m2. Rose of sharon ‘Red Heart’ prefers potash fertilizer rather than phosphate fertilizer. Newly planted plants may also require additional, quick-acting, liquid fertilizer weekly.
Planting Instructions
The best planting season for rose of sharon ‘Red Heart’ is during fall while it is still warm. This allows the root to recover in warm soil, encouraging vigorous growth the following year. A location that receives sufficient sunlight and is slightly shaded in the afternoon is best for planting rose of sharon ‘Red Heart’, depending on the local sunshine projection. All weeds should first be removed before planting, and then a planting pit can be dug. The pit should be at least twice the diameter of the root ball and attached soil, and slightly deeper than the root ball’s height.
For potting, try to choose a dwarf variety and the largest flowerpot possible. The flowerpot should be of sufficient weight and stability, with stone pots preferred. Pot depth should be at least 1.5 times the depth of the root ball. The diameter should be 1/6-1/4 of the height of the adult plant. Place 3 cm of rough stones at the flowerpot bottom for better drainage.
Sort and scatter the root ball, place it in the flowerpot or planting pit, and then gradually backfill and compact the soil. Cut off any diseased, damaged, inward-growing, or crossed branches and other branches that affect the plant’s shape. Water thoroughly and spread a 5 to 7 cm layer of decomposed medium or crushed bark. If the plant is a standard seedling type with a single trunk, insert a stake before planting to support the plant.
Pruning
Rose of sharon ‘Red Heart’ 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
A beloved ornamental, rose of sharon ‘Red Heart’ thrives when propagated through cuttings, encouraging gardeners to select healthy, vigorous stems. Effective propagation involves snipping a portion of semi-hardwood at a node, ensuring a few leaves remain. Dipping the cut end in rooting hormone enhances root development when placed in well-draining soil. Keeping the medium moist and providing a warm environment supports successful rooting, transferring rose of sharon ‘Red Heart”s vibrant charm to new settings.
Transplanting
To give rose of sharon ‘Red Heart’ a thriving start, relocate it during the warmth of post-spring to pre-summer, ensuring full to partial sun exposure. Select a spot with well-draining soil to establish its roots seamlessly.
III. 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.
