Hibiscus, Rose of Sharon, Shrub Althea 'Red Heart'

Hibiscus syriacus

Family: Malvaceae (mal-VAY-see-ee) (Info)
Genus: Hibiscus (hi-BIS-kus) (Info)
Species: syriacus (seer-ee-AK-us) (Info)
Cultivar: Red Heart
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8-10 ft. (2.4-3 m)


4-6 ft. (1.2-1.8 m)


USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

Sun Exposure:

Sun to Partial Shade

Bloom Color:


White/Near White

Bloom Time:

Mid Summer

Late Summer/Early Fall



This plant is resistant to deer

Other details:

Unknown - Tell us

Soil pH requirements:

6.6 to 7.5 (neutral)

Patent Information:


Propagation Methods:

From woody stem cuttings

From softwood cuttings

From semi-hardwood cuttings

From hardwood cuttings

Self-sows freely; deadhead if you do not want volunteer seedlings next season

Seed Collecting:

Allow pods to dry on plant; break open to collect seeds

Foliage Color:


Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Requires consistently moist soil; do not let dry out between waterings

Where to Grow:

Unknown - Tell us


This plant is said to grow outdoors in the following regions:

Tuscaloosa, Alabama

Carmichael, California

Crockett, California

Deland, Florida

Fort Walton Beach, Florida

Conyers, Georgia

Chicago, Illinois

Saint Cloud, Minnesota

Saucier, Mississippi

Jefferson City, Missouri

Blair, Nebraska

Kearney, Nebraska

Lincoln, Nebraska

Auburn, New Hampshire

Jersey City, New Jersey

Willingboro, New Jersey

Croton On Hudson, New York

Cleveland, Ohio

Dayton, Ohio

Dundee, Ohio

Glouster, Ohio

Painesville, Ohio

Westerville, Ohio

Hulbert, Oklahoma

Oakland, Oregon

Salem, Oregon

Clairton, Pennsylvania

Coatesville, Pennsylvania

Lebanon, Pennsylvania

Pittsburgh, Pennsylvania

Greenville, South Carolina

Greeneville, Tennessee

Jackson, Tennessee

Summertown, Tennessee

Talbott, Tennessee

Arlington, Texas

Longview, Texas

North Zulch, Texas

San Antonio, Texas

Santa Fe, Texas

South Jordan, Utah

Cathan, Washington

John Sam Lake, Washington

Langley, Washington

North Marysville, Washington

Priest Point, Washington

Shaker Church, Washington

Stimson Crossing, Washington

Weallup Lake, Washington

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Gardeners' Notes:


On Jun 30, 2011, SummerGirl55 from Lebanon, PA (Zone 6a) wrote:

This plant provides a great hedge border for privacy. I love all the different colors it provides. Does anyone know how to keep all the little seedlings from being deposited literally everywhere? Thanks


On Sep 23, 2004, WUVIE from Hulbert, OK (Zone 7a) wrote:

Indeed a gorgeous beauty well deserving of a pruning
to encourage those gorgeous blooms in larger sizes!
A stunning althaea with a bloody burst in the center
gets their attention every time.


On Jun 2, 2004, OhioBreezy from Dundee, OH (Zone 5b) wrote:

Grows easily from seed. Can be kept pruned to fit a smaller space if required without harming the plant. Very fast grower! Also blooms later in season when most other shrubs are finished blooming. No scent to the blooms.