Rose of Sharon ‘Red Heart’ (Hibiscus ‘Syriacus Red Heart’)

Hibiscus 'Syriacus Red Heart' is commonly sold in the United States as Rose of Sharon 'Red Heart' or Red Heart althea. It is a deciduous flowering shrub, not the tropical hibiscus typically grown as a seasonal patio plant.

Plant Rose of Sharon 'Red Heart' in full sun for the best flowering, although it tolerates partial shade. Aim for at least 6 hours of direct sunlight daily when possible.

Water Hibiscus 'Syriacus Red Heart' moderately, keeping the soil evenly moist while the plant establishes. Once established, it usually needs supplemental water only during extended dry periods, extreme heat, or drought.

Hibiscus 'Syriacus Red Heart' is a hardy outdoor shrub in much of the United States, commonly listed for USDA Zones 5–8. Cold protection may still help newly planted shrubs in exposed northern locations.

Rose of Sharon 'Red Heart' grows in moist but well-drained loam, clay, or sandy soil. Improve heavily compacted or poorly drained ground with organic matter, but do not plant it where water remains pooled.

Yes, Hibiscus 'Syriacus Red Heart' can grow in clay soil if drainage is adequate. Avoid planting it in permanently waterlogged clay, and amend or mound the planting area if water drains slowly.

Hibiscus 'Syriacus Red Heart' typically grows about 8–10 feet tall, with a similar spread under favorable conditions. Its final size varies with pruning, soil, sunlight, climate, and the quality of the planting site.

Rose of Sharon 'Red Heart' can be grown as a flowering hedge because it develops an upright, semi-upright form and tolerates routine shaping. Space plants according to their mature width rather than placing them tightly together.

Yes, Hibiscus 'Syriacus Red Heart' generally tolerates summer heat and humidity once established. Consistent moisture during prolonged heat helps prevent stress and supports better flowering.

Rose of Sharon flowers can attract butterflies, hummingbirds, and other flower-visiting insects. The open blooms of 'Red Heart' are especially accessible compared with heavily double-flowered cultivars.

The most common causes are insufficient sunlight, excessive nitrogen, drought stress, or late pruning that removes new flowering wood. Move or thin nearby shade, water during prolonged dryness, and prune in late winter or early spring.

Hibiscus 'Syriacus Red Heart' is naturally one of the later shrubs to leaf out in spring. Wait for consistently warm weather before assuming it is dead, while checking stems for flexible green tissue.

Fertilize Rose of Sharon 'Red Heart' only if growth is weak or a soil test indicates a nutrient deficiency. A general-purpose slow-release fertilizer applied in spring is usually safer than repeated high-nitrogen feeding, which can favor leaves over flowers.

Hibiscus 'Syriacus Red Heart' may occasionally be affected by aphids, scale insects, or other sap-feeding pests. Inspect new growth and leaf undersides, and use a low-impact treatment only when pests are causing noticeable damage.

Rose of Sharon 'Red Heart' can develop powdery mildew, especially in humid conditions with poor air circulation. Give it adequate spacing, avoid wetting the foliage late in the day, and remove severely affected debris.

Established Rose of Sharon 'Red Heart' usually needs no special winter protection within its hardiness range. In colder or windy areas, apply a few inches of mulch over the root zone after the ground cools, keeping mulch away from the stems.

Plant Hibiscus 'Syriacus Red Heart' in spring after the ground is workable or in early fall while soil remains warm. Avoid planting during frozen ground, extreme summer heat, or drought unless you can provide reliable irrigation.

Set Rose of Sharon 'Red Heart' at the same depth it grew in its nursery container, or slightly high in heavy soil, and make the planting hole wider than the root ball. Water deeply after planting and keep the root zone evenly moist during establishment.

Hibiscus 'Syriacus Red Heart' can be grown temporarily in a large container, but its eventual 8–10-foot size makes in-ground planting preferable. Use a pot with drainage holes and refresh or replace the container as roots become crowded.

Propagate Rose of Sharon 'Red Heart' most reliably from semi-hardwood or softwood stem cuttings. Take healthy nonflowering shoots, place them in a sterile, well-drained rooting medium, and maintain steady moisture and humidity.

Seed is not the best way to reproduce Hibiscus 'Syriacus Red Heart' because seedlings may not retain the parent plant’s flower color or form. Cuttings are preferred when you want a new plant true to the named cultivar.

Prune Rose of Sharon 'Red Heart' in late winter or early spring before new growth begins. Because it flowers on new wood, this timing preserves the season’s bloom while allowing you to shape or reduce the shrub.

Yes, Hibiscus 'Syriacus Red Heart' tolerates significant late-winter pruning, although severe cuts can produce vigorous upright shoots and a less natural form. Pruning back to a few buds may create larger flowers, while lighter thinning preserves more structure.

Deadheading is optional for Rose of Sharon 'Red Heart' but can improve appearance and reduce unwanted seed development. Remove spent flowers or developing capsules before they mature if you want to limit volunteer seedlings.

Hibiscus 'Syriacus Red Heart' is considered non-toxic to dogs and cats according to species-level veterinary plant references. Pets can still experience stomach upset after eating large amounts of any plant material, so contact a veterinarian if symptoms occur.

Rose of Sharon 'Red Heart' can spread by seedlings or volunteer plants in some gardens, although reports differ on how freely this particular cultivar reproduces. Remove developing seed capsules and unwanted seedlings if you need to prevent spread.

Hibiscus 'Syriacus Red Heart' is not generally considered a thorny shrub. Its branches can still be woody and scratch skin during pruning, so wear gloves and use clean, sharp tools.

Rose of Sharon 'Red Heart' produces white, hibiscus-like flowers with a strongly contrasting dark red center. The blooms are typically single and appear on the season’s new growth.

Hibiscus 'Syriacus Red Heart' generally blooms from midsummer into late summer or early fall, depending on climate and growing conditions. Full sun, adequate moisture, and spring pruning support the heaviest flowering.

Small flowers may result from insufficient sun, drought, weak growth, or lack of rejuvenation pruning. Late-winter pruning to a few healthy buds can encourage larger blooms, but excessive nitrogen may reduce flowering quality.