Hibiscus Sinensis

darran · Post by **darran** » Wed Oct 31, 2007 8:22 pm

I know this is a long shot and I probably already know the answer but can Hibiscus Sinensis be overwintered outside? Would wrapping in fleece, etc. be of any use and are any of the colours more hardy than others?

If this is of use, I live to the west of London and for the 4 or 5 years I have had Lantanas overwintered outside against a sunny wall with no protection of any kind.

Any advice more than welcome.

Darran

Chad · Post by **Chad** » Wed Oct 31, 2007 8:47 pm

Hibiscus rosa-sinensis should take -5C without dying back to the soil, but the roots don't like our long cold damp winters. Sharp winter drainage and heat the summer before to ripen the wood are probably more important than the winter minimum temperature.

If you can give it a spot under the eaves so that it can be fairly dry in winter, you stand a fighting chance. It fails with me outdoors in Cornwall. Not enough summer heat.

Chad.

darran · Post by **darran** » Wed Oct 31, 2007 9:03 pm

Thank You! That is far more encouraging than I expected, and with your advice in mind, I will try leaving a couple of the plants in situ with some fleece at the ready for those colder nights!

I have quite a few that have been rescued from garden centre bargain areas when they have finished flowering, so it will not be a costly mistake if they fail to come through!

Chad · Post by **Chad** » Wed Oct 31, 2007 9:10 pm

If you several to experiment with, you could try cutting some down to a stump and covering with a large cloche. That would give the roots a drier time.

Chad.

Post by **Dave Brown** » Wed Oct 31, 2007 9:11 pm

Im surprised Chad, I have lost several in the conservatory at about +6C

Chad · Post by **Chad** » Wed Oct 31, 2007 9:19 pm

Well.....

I've lost them more often than I've gotten them through. USA sites quote hardy to -7C ish [zone 9a], but that would be the occasional quick freeze.

I was suggesting the experiment to find out if it worked.

On the estate where I was brought up they were cut back hard, and overwintered just frost free, but DRY. I don't know how succesfully though. I was young then and not watching properly...

Chad.

Post by **Dave Brown** » Wed Oct 31, 2007 9:29 pm

Yes...but I think USDA zones are totally inappropriate for UK gardening. 9a is around Florida. So basically they will survive in the Canary Islands down to -7C.

Chad · Post by **Chad** » Wed Oct 31, 2007 9:33 pm

I agree. London can overwinter stuff that I can't even though I am warmer. a lot of stuff doesn't like my summer cool, and winter wet. I have trouble with lavender!

But, I have gotten H.rosa-sinensis through under cover with -4 ish. Short lived temperature drop, and dry.

Chad.

turtile · Post by **turtile** » Wed Oct 31, 2007 9:49 pm

Did you try Hibiscus Coccineus?

Its hardy to Zone 6 and colder with mulch. I am currently growing the "Texas Star" variety which I can collect some seed.

Sinensis does grow in Zone 9a, Florida.

bodster · Post by **bodster** » Wed Oct 31, 2007 10:58 pm

i do find that the shrubby hardy type hibiscus plants are root hardy but the summers here just aren't long enough for them to actually flower

Don · Post by **Don** » Thu Nov 01, 2007 12:00 am

bodster wrote:i do find that the shrubby hardy type hibiscus plants are root hardy but the summers here just aren't long enough for them to actually flower

True-or at least when they finally start to flower the first frost wrecks them. Shredded mine two years ago

grub · Post by **grub** » Thu Nov 01, 2007 12:34 am

now knowing its an ensis, where do i find sin?

Don · Post by **Don** » Thu Nov 01, 2007 12:41 am

grub wrote:now knowing its an ensis, where do i find sin?

Sik Kim (the Tai Girl) might help

turtile · Post by **turtile** » Thu Nov 01, 2007 12:43 am

bodster wrote:i do find that the shrubby hardy type hibiscus plants are root hardy but the summers here just aren't long enough for them to actually flower

I guess you don't have enough heat. Our summer is around the same length as yours but its much hotter.

They need full sun and moist soil to flower best. They are native to my area and grow on the water's edge of ponds and creeks.

Alexander · Post by **Alexander** » Wed Nov 07, 2007 3:15 am

The best alternative for Hibiscus rosa sinensis is Hibiscus palustris and H. moscheutos. They are very hardy and even this year I had them into flower after a cold rainy August. H. cocineus I also have and it even had flowerbuds but no flowers. If you plant it close to a southfacingwall and in a warmer part of Britain you could be lucky to get it into flower. But H. palustris and H. moscheutos are much better.Here in Lweidschendam, close to the coast summers are very similair to some parts of Britain. And places like Kent and London are much warmer!

I have young plants and seeds of Hibiscus palustris and I also have some older H. cocineus plants.

Both species are perennials.

Regards,

Alexander