Winter hardy hibiscus

[Ted]

A couple weeks ago, I found at Home Depot, and bought, what they called a "Rose of Sharon". It didn't look like any rose I've ever seen. Instead its flowers looked like small, about 6 or 7 cm across (or about

2.5 inches), hibiscus flowers. Their horticulturalist said it is winter hardy here (just a two hour highway drive north of Toronto Ontario Canada), but that it tends to be a bit tender here. (suggestions on protecting it, if in fact it is hardy here, would be appreciated)

Today, I saw some plants, labelled as hibiscus at a grocery, and the card that came with the plants from the store's suppliers says it is hardy to USDA zone 5 (which I think includes us here). I thought hibiscus were strictly tropical, and that the "rose of Sharon" I bought might be a temperate cousin (smaller, hibiscus-like flowers on shrubby stems). But the "hibiscus" I saw today looked to be as large and colourful as those tropicals I'd seen at real garden centres, but on stems that seemed as delicate as the stems of my begonias, with no trace of wood. The card from the supplier said it would die down over winter and start new growth in May, and then bloom until first frost. While the flowers were as large as the tropical hibiscus I'd seen, they didn't seem to have as much substance (a more papery look), but I don't know if that is damage from the excessive heat we've had this summer. My irises and lilies gave a less than adequate display this year because of the heat. The card with them also said they'd stay small, two thirds of a metre to a metre tall at most.

Anyway, is there really a hibiscus species or hybrid that is winter hardy in a cool temperate region with such delicate stems? Or are these plants certain to die like annuals here?

Can anyone shed light on this?

Thanks,

Ted

[Marley1372]

HIbiscus is a tricky genus. The most common plants you will find are:

Tropical hibiscus- (H. rosa-sinensis) These are not hardy and are mainly sold as house plants in your area.

Perennial hibiscus- (H. moscheutos and the less common H. coccineus) Both are hardy to zone 5 and have the same size flowers as the tropical kind.

Rose of sharon (H. syriacus) Often sold as "althea" or sometimes "hardy hibiscus". This is a woody shrub with much smaller flowers than the above mentioned, but essentially the same appearence otherwise. Hardy to zone 5, but bad winters can do them in sometimes.

Hope this helps! Searching google images with the botanical names will probably turn hup lots of pictures.

Toad

[Cereus-validus.......]

Hibiscus is a rather large genus found worldwide and includes shrubs, perennials and annual species. Some of the Chinese shrub species, such as Hibiscus syriacus, are cold hardy but the majority of the shrubby species and their hybrids are strictly tropical. The perennial species in the Hibiscus moscheutos group of the eastern US and their hybrids are also cold hardy. There are also a number of annual species that are seldom seen in gardens.

[carbuff]

FWIW, here's my experience with Home Depot hibiscus. Around 6 weeks ago, they had a weekend special - 48 inch plants in 10 inch pots for $19.99 Bought two, they looked a little root-bound, so bought a couple ceramic planters and re-potted with good soil + compost. Did a Google search on hibiscus which general consensus said: full sun and heat. WRONG!!!! The few blooms that appeared lasted only 1 day, and slowly the leaves started to turn yellow. Figuring that there was nothing to lose, I moved the pots to the north side of the house, on each side of the attached garage. There is a 3foot overhang, so they get indirect light for the majority of the day, not to mention it's cooler there. They are now thriving, no yellow leaves, and the blooms are proliferating and lasting several days now. They are a gorgeous shade of apricot, which I had never seen before. YMMV BTW, I am in Winnipeg, which is Zone 3, if it matters.

P.S. They seem pretty thirsty, almost like hydrangeas.

[Cereus-validus.......]

You should expect the plants to respond differently when grown in pots than being planted out in the ground. Grown in pots the plants will need more water, fertilizing and protection from full sun.

No matter how you grow the plants, individual Hibiscus flowers open only for a single day.

Your plant are probably deciduous perennial Hibiscus hybrids. What do you plant to do with them over the winter when they die back to the rootstock? You should plant them out in a permanent position in the garden.

[clc]

OK Ted, Rose of Sharon will survive in Zone 5 - I'm in Central IL and mine do well with no form of protection. Do yours have more of a woody stalk? You're right, the flowers do look like small hibiscus and in no way resemble roses.

The hibiscus you saw at the grocery could very likely be hardy to Zone 5. Were the leaves on the plant fairly large compared to tropical leaves and dull in appearance? If so, that is hardy. Tropical hibiscus leaves are totally different in appearance, they are are much shinier. I have what I call a "dinner plate" hibiscus which is hardy and the blooms are easily 10" in diameter (none of my tropicals ever get that large).

All of my hibiscus, whether hardy or tropical thrive in full sun with plenty of food and water.

Cheryl

[Ted]

Thanks loads one and all. I learned plenty. Further, a vendour of fine plans located in Michigan tells me that some Hibiscus are winter hardy to USDA zone 4.

Anyway, the Hibiscus I bought from the grocer had no trace of wood in stem. They strike me as being as delicate and succulent as the stems of the begonias I have in pots out front.

The leaves on it are larger than other hisbiscus I have seen and rather dull. Certainly no sheen on them as I have noticed on other hibiscus.

For the time being, I am leaving them in pots. This is because I plan on creating raised beds in the front garden (a southern exposure, but shade from noon to late afternoon and full sun the rest of the day - due to a huge maple to the south west of the bed). I don't want to plant them now only to move them in the fall. While I am not fond of raised beds, this seems a necessary compromise since I have trouble with my feet and lower legs (it seems to me just a matter of time before my diaetes takes them), I can not get down on my hands and knees; if I did so, I would not be able to get up again. And I can not weed the garden standing up. With a raised bed, at least I could sit on the edge of the bed while I am weeding. And this is something that you have to do yourself if you want it done right.

Thanks again all,

Ted

R.E. (Ted) Byers, Ph.D., Ed.D. R & D Decision Support Solutions

Healthy Living Through Informed Decision Making

[told2b]

Does this apply to Rose of Sharon (Hibiscus syriacus) too? Thanks

[presley]

[Cereus-validus.......]

Of course it does.

The double flowered cultivars seem to last longer because of the extra petals but they only open to full size for only one day.

[Ted]

Thanks. I didn't know that. To date, the only plants I have kept indoors have been orchids.

In any event, I expect I'll be keeping them in pots only until this fall when I put in a raised bed. I just didn't want to plant them now, only to replant them in a couple months when the work with the raised beds is done.

Thanks,

Ted

R.E. (Ted) Byers, Ph.D., Ed.D. R & D Decision Support Solutions

Healthy Living Through Informed Decision Making