Photo by Melody

PlantFiles: Rose of Sharon
Hibiscus syriacus 'Tosca'

Family: Malvaceae (mal-VAY-see-ee) (Info)
Genus: Hibiscus (hi-BIS-kus) (Info)
Species: syriacus (seer-ee-AK-us) (Info)
Cultivar: Tosca

» View all varieties of Hibiscus

8-10 ft. (2.4-3 m)

24-36 in. (60-90 cm)
36-48 in. (90-120 cm)
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:
Magenta (Pink-Purple)

Bloom Time:
Mid Summer
Late Summer/Early Fall


Other details:
This plant is attractive to bees, butterflies and/or birds
Average Water Needs; Water regularly; do not overwater

Soil pH requirements:
Unknown - Tell us

Patent Information:
Unknown - Tell us

Propagation Methods:
From woody stem cuttings

Seed Collecting:
N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed


1 positive
No neutrals
No negatives

Gardeners' Notes:

Positive Dean48089 On Jun 17, 2013, Dean48089 from Warren, MI (Zone 6b) wrote:

The entry for this plant is somewhat misleading. Hibiscus 'Tosca' is a hybrid between our native Hibiscus paramutabilis and Hibiscus syriacus, possessing features from each parent. I first bought 'Tosca' and 'Lohengrin' at the same time from Glasshouse works about 13 years ago. I planted them in a spot expecting growth similar to H. syriacus, which is a slow grower in my heavy clay soil. By their third summer both 'Tosca' and 'Lohengrin' were over twelve feet tall and at least six feet wide, overwhelming all their neighbors. So I cut them both down to 2' stumps with the intention of letting them grow back in a more controlled manner. 'Tosca' did not appreciate this treatment and the stump died. Fortunately, taking after its H. paramutabilis parent, the plant sends up the occasional sucker and so I moved one of those to a different location. Ten years later that sucker is now a small thicket of several plants that are at least 15' tall with about an 8' spread. I do prune 'Tosca' to discourage horizontal branching but I don't do anything to control the height. The flowers are much larger than either parent, rivaling the tropical H. rosa-sinensis in size. 'Tosca' is self-dead heading and it has never set seeds. The reason I cut back any horizontal branches is because such branches are fully leafed out and then start to bloom they get too heavy to hold themselves up. If I had a larger yard I wouldn't mind having a row of 'Tosca.'


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

Warren, Michigan

We recommend Firefox
Overwhelmed? There's a lot to see here. Try starting at our homepage.

[ Home | About | Advertise | Media Kit | Mission | Featured Companies | Submit an Article | Terms of Use | Tour | Rules | Privacy Policy | Contact Us ]

Back to the top

Copyright © 2000-2015 Dave's Garden, an Internet Brands company. All Rights Reserved.

Hope for America