Swamp rosemallow
Hibiscus grandiflorus

Family: Malvaceae (mal-VAY-see-ee) (Info)
Genus: Hibiscus (hi-BIS-kus) (Info)
Species: grandiflorus (gran-dih-FLOR-us) (Info)
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Height:

6-8 ft. (1.8-2.4 m)

8-10 ft. (2.4-3 m)

Spacing:

24-36 in. (60-90 cm)

36-48 in. (90-120 cm)

Hardiness:

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)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

USDA Zone 11: above 4.5 C (40 F)

Sun Exposure:

Sun to Partial Shade

Bloom Color:

Pale Pink

Bloom Time:

Late Spring/Early Summer

Mid Summer

Late Summer/Early Fall

Foliage:

Evergreen

Other details:

Unknown - Tell us

Soil pH requirements:

5.6 to 6.0 (acidic)

6.1 to 6.5 (mildly acidic)

Patent Information:

Unknown - Tell us

Propagation Methods:

By dividing rhizomes, tubers, corms or bulbs (including offsets)

From herbaceous stem cuttings

Seed Collecting:

Bag seedheads to capture ripening seed

Foliage Color:

Unknown - Tell us

Bloom Characteristics:

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

Water Requirements:

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

Where to Grow:

Unknown - Tell us

Regional

This plant has been said to grow in the following regions:

Deltona, Florida

Lutz, Florida

Savannah, Georgia

Union, Kentucky

Nutley, New Jersey

Durham, North Carolina

Pittsboro, North Carolina

Conway, South Carolina

Norfolk, Virginia

Rosedale, West Virginia

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Gardeners' Notes:

4
positives
1
neutral
0
negatives
RatingContent
Positive

On May 14, 2014, Nkytree from Burlington, KY wrote:

This plant is much more cold hardy than given credit for. It has survived -9F this past winter at Boone County Arboretum (northern Kentucky, zone 6a) with no extra protection other than 2-3 inches of mulch inside a flower bed.

Vistitors simply love this plant, even if it never bloomed it would be much admired for the handsome velvety foliage! When it blooms the plant is simply stunning.

Positive

On May 13, 2011, Michael_Ronayne from Nutley, NJ (Zone 6b) wrote:

With a winter mulch of about 1 foot of salt-hay I was successfully able to overwinter Hibiscus grandiflorus in USDA Zone 6b in Northern New Jersey. In New Jersey the H. grandiflorus bloomed the first year and broke dormancy in the first week in May.

Mike

Neutral

On Jan 29, 2009, htop from San Antonio, TX (Zone 8b) wrote:

I have not grown this plant. Swamp rosemallow (Hibiscus grandiflorus) is native to Alabama, Florida, Georgia, Louisiana, Mississippi and Texas. It is also commonly known as giant rose mallow, swamp hibiscus, velvet mallow and giant hibiscus. It is native to fresh and brackish marshes and the edges of swamps, ponds, streams and ditches and can be grow where other plants succumb to salty soil. The up to 10 in (25 cm) long and across, 3- to sometimes 5- lobed, palmate leaves are a gray-green and have a velvety upper and underside surface. Unlike many hibiscus species, the plant has dense foliage. Because of its soft leaves, it is sometimes referred to as toilet paper hibiscus. Swamp rosemallow is evergreen in mild climates; however, in colder climates, it will freeze to the ground and ... read more

Positive

On Jan 17, 2007, mikeys_gardn from Deltona, FL (Zone 9b) wrote:

A beautiful native, this is found in low lying swampy areas. One of my favorite plants with big pinkish flowers . Its a fairly upright plant sending tall shoots in the spring and flowering by July / August. In the fall it begins to decline but comes back in the spring even stronger.

Positive

On Sep 24, 2005, Hogwaump from Rosedale, WV (Zone 7b) wrote:

Excellent for swamp control. It will spread until it runs out of swamp and suck up the water, reducing or eliminating mosquitos.