Paraplu Violet® rose of Sharon. Photo by Proven Winners.

Hibiscus plants aren’t only for the tropics. In fact, some hardy hibiscus varieties, like the popular rose of Sharon, can overwinter outdoors in temperatures as cold as 20° below zero.

On this page: Basics | Planting | Care and Maintenance | Pictures | Design Ideas | Is rose of Sharon invasive?

On this page:

Buy rose of Sharon plants from Proven Winners.

BASICS

Botanical name:

Hibiscus syriacus

Common names:

Rose of Sharon, shrub althea; also shares the common name hardy hibscus with Hibiscus moschuetos.

Zones:

Generally 5-9, with some exceptions.

Height/Spread:

8 to 12 feet tall, 6 to 10 feet wide, depending on the variety

Exposure:

Full sun to partial afternoon shade (best flowering in full sun).

Soil:

Prefers moist, yet well-drained soil; mulch to help retain moisture.

Bloom Time:

Rose of Sharon bushes start blooming in July and continue into fall or until the first frost.

Flower Color:

Shades of white, pink, red, and purple; sometimes with a contrasting throat.

Foliage:

Deciduous; with medium-green, heart- or maple-shaped leaves, although there are a few exceptions.

PLANTING

Blue Chiffon® Rose of Sharon. Photo by: Proven Winners

When to plant:

Rose of Sharon plants and other hardy hibiscus varieties can be planted in spring or fall, as long as there is no danger of frost.

Where to plant:

Full sun to partial afternoon shade. An area with good air circulation produces the best flowers and strongest stems, and is the best environment to prevent disease. Keep an eye out for hot, scorching afternoon sun that may burn the foliage; as well as provide protection from damaging wind.

How to plant:

Seeds can be started indoors and then transplanted, but it is more common to plant potted plants purchased from a nursery. Dig a hole twice the width of the pot and set the plant in. Make sure the crown of the plant rests just at or above the soil line. Backfill the hole, and water well.

CARE

Fertilizer:

Hibiscus need a fertilizer high in potassium (K), low in phosphorus (P), and with a medium amount of nitrogen (N)—too much phosphorus will kill a hibiscus. Hibiscus also respond well to an organic fertilizer, and a good layer of compost once a year is generally sufficient. Don’t fertilize after July as this can push new growth that will be damaged by frost.

Water:

They prefer moist soil and do not tolerate drought. Water regularly and up to twice a day in hotter weather, especially if in a container. Cut water back a bit in colder weather. Water-stressed hibiscus may drop their buds or become more susceptible to insects and disease. They should not be left in standing water as this can promote root damage/root rot.

Magenta Chiffon® rose of Sharon. Photo by: Proven Winners

Pruning:

Little pruning is required, and is generally only needed to maintain appearance, size, and shape. They can be cut back 4-6 inches from the ground in spring, anytime before the new growth emerges. Pruning before very cold temperatures or in extreme heat can be very stressful to your plant and do more harm than good.

Tip pruning can stimulate branching, and since more branching means more flowers, a little trim late spring to early summer can be a good thing.

Deadheading:

To help prevent an over-abundance of seed pods from forming (some varieties may re-seed abundantly). (Or, for a similar look, try the non-seeding Summerific® series rose mallows.)

Overwintering:

Hardy varieties will die back to the ground in the winter in colder regions, but new growth will develop from the roots in mid to late spring from the root tops. In colder climates, cover the root ball with mulch to insulate it.

Diseases and Pests:

Hardy hibiscus can fall prey to a number of pests, including Japanese beetles, whiteflies, aphids, and ants. Ants can be more than a mere annoyance on your hibiscus, as they will actually bring aphid eggs to the hibiscus so that they can feed off of the byproducts the aphids produce from sucking the sap from the leaves and flowers. Hibiscus may be susceptible to dieback disease, wilt disease, and leaf fungus.

HIBISCUS PICTURES

Swipe to view slides

Photo by: Proven Winners

Blue Chiffon®Buy now from Proven Winners
Hibiscus syriacus

Zones: 5-9

Height/Width: 8 to 12 feet tall, 4 to 6 feet wide

Grows vigorously with a rounded habit. Flowers have a fluffy center and produce few seeds. Provides beautiful blue late summer color in the garden.

Awarded 2020 Flowering Shrub of the Year by Proven Winners.

Also available in lavender, dark lavender, pink, magenta, and white.

Photo by: Proven Winners

Purple Pillar®Buy now from Proven Winners
H. syriacus

Zones: 5-9

Height/Width: 10 to 16 feet tall, 2 to 3 feet wide

A unique variety that grows tall and narrow, instead of wide, making it a great choice for privacy screening, hedging, containers, or any narrow space. Semi-double flowers bloom along the entire length of the stems. Little to no pruning is needed.

Also available in White Pillar®.

Photo by: Proven Winners

Sugar Tip® GoldBuy now from Proven Winners
H. syriacus

Zones: 5-9

Height/Width: 48 to 60 inches tall and wide

Another cultivar that produces far fewer seeds than standard varieties, making it nearly maintenance free.

See others in the Sugar Tip® series.

Photo by: Proven Winners

Lil Kim®Buy now from Proven Winners
H. syriacus

Zones: 5-9

Height/Width: 3 to 4 feet tall and wide

This dwarf rose of Sharon packs a punch with packed stems of showy white and red flowers.

See others in the Lil Kim® series.

Photo by: Proven Winners

Paraplu Violet®Buy now from Proven Winners
Hibiscus hybrid

Zones: 5-9

Height/Width: 5 to 8 feet tall, 4 to 5 feet wide

The cool blue-violet flowers bring a glow to the garden and bloom for weeks.

See others in the Paraplu® series.

Photo by: Proven Winners

Ruffled Satin® Buy now from Proven Winners
Hibiscus hybrid

Zones: 5-9

Height/Width: 8 to 10 feet tall and wide

Large and showy, rich pink ruffled flowers have burgundy centers. Low seed-set is an added bonus.

See others in the Satin® series.

Photo by: Proven Winners

Pollypetite® Buy now from Proven Winners
Hibiscus hybrid

Zones: 5-9

Height/Width: 3 to 4 feet tall and wide

This compact, nearly seedless rose of Sharon ensures that everyone has room to grow one of these beauties!

DESIGN TIPS

  • Excellent foundation plant, anchoring structures to the landscape; planting close to buildings also provides some cold protection for the plant.
  • Hibiscus are some of the most colorful plants in the landscape, so be careful not to overwhelm an area or have clashing tones.
  • Generally grown as multi-trunked shrubs, rose of Sharon can also be trained as a single-trunk small tree or espalier.
  • Hardy hibiscus are not good for cut flowers, as their blooms only last a day or two. Dried seed pods can provide an exotic look and last longer in an arrangement.

IS ROSE OF SHARON INVASIVE?

Hibiscus syriacus can be invasive in the following areas:

  • Most of Indiana
  • Parts of the South
  • Coastal areas of the Mid-Atlantic

To see if rose of Sharon has been identified as invasive in your area check out this map from InvasivePlantAtlas.org.

Last updated: July 16, 2021

Related:
Growing Rose Mallow (Swamp Hibiscus)
Flowering Shrubs
Tropical Gardens

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