Hibiscus Flower Zone 5. The plant is only hardy in zones 10 through 11 New Hampshire is a Zone 5-6 for the most part so its usually grown as a potted annual by Northern gardeners. You may also consider growing rose of Sharon which is a hardy shrub variety of hibiscus that grows well in zones 5 through 9.
Closely related to hollyhock hardy hibiscus can get pretty large so select a spot that can accommodate its 6 foot 2 m height and 4-6 foot 1 to 2 m width. The large pink dark-eyed flowers of Lady Baltimore Hibiscus are sure to make a statement in the late spring and summer garden. You can prune the dead parts of the plant close to the ground.
Being a deciduous shrub these.
The Latin name for Tropical Hibiscus is Hibiscus rosa-sinensis. Sep 10 2008 Since their cold hardiness is limited to zone 5 there are reliable bloomers in protected locations in central and southern Iowa. Zone 9 hibiscus grown in ground should be a hardy variety rather than a tropical if you wish to have a perennial. Aug 19 2020 Perennial hibiscus do best in zones 5-9 21 degrees F-1 degrees C at coldest but tropical hibiscus need warmer temperatures flower best at 60-90 degrees F16-32 degrees C.