Do you have a greenhouse or sunporch where you can keep it indoors over winter? They don't like temps below freezing, and can also be temperamental about root rot under low winter light, cool(below 50F) temps of winter, so the warmer you can keep it over winter, it will stay in active growth. If you get it bulked up enough this season, you may also be able to treat it like a Brugmansia and stick it the garage or basement and let it go dormant, but this may be riskier than keeping it actively growing through the winter. Mandevilla can also be fairly easy to root from cuttings, so maybe try both methods.

Mandevilla can stay outdoors here in coastal California and be perennial, but they tend to sulk here in northern California with our winter wet and cool, and the tuberous roots are very easy to rot out if they get too wet.

Suetran1,
I have never seen a double mandevilla!
It is beautiful!
Where did you get it?
It is absolutely beautiful!
I would want to keep it too if I were you.
Thanks for showing me the pic!

That is just beautiful. I've never seen a double mandevilla. I used to keep mine under the HID lights over the winter but never failed to get terrible mealy bug and scale infestations so now I cut them back to a couple inches and let them go dormant over the winter. I keep them in an unheated greenhouse that stays above freezing but not by much. I water them very little and no fertilizer. When it starts warming up in March I begin watering and when new growth begins I start feeding. Last year was the first time I let them go dormant. It takes longer to get blooms but I don't have to worry about bugs.
Karyn

I would also like to know where you got the double mandevilla. I have over wintered mandevillas in a sunny window with good results. It takes a while for them to bloom after going outside but they do well. I am going to try cuttings under a shop light in vermiculite and put into ziplock bags. I'll let you know how it works. judysugarsmama

I too would love to know where you got this!!! I would love to ask for one for Valetine's or Mother's Day.

barnbatt

Thanks everyone for the tips
When I saw it at the farmer market in Raleigh,NC.
On the label is Mandevilla x amoena/Apolynaceae.
I bought it for $15 in May/08. I did not see they sell this anymore. I will try cutting too, if it works i will let you know.
I think I will keep it cool in my garage, my greenhouse will be too warm. I don't know if it needs to be rest in winter?

I've never had good results with mandevilla cuttings but layering works quite well. I just lay a branch on the ground and cover it with a bit of soil. It roots in about 6 weeeks.
Karyn

I've had a double mandevilla for over 7 years. In Illinois! Monrovia Nursery has a double. As to overwintering, I wait till the last possible minute to bring it indoors. In the fall I give it boost of fertilizer to toughen it up and then lighten up on the water while it is inside. I keep it on wet pebbles to keep up the humidity. It will drop some leaves and some of the vine will die back but I just cut it back to the new growth and as soon as the weather warms above the high 40's at night she goes out onto the porch. If we get a cold snap I leave the porch lights on over night and protect it from the wind. It takes a little longer to bloom than fresh nursery stock every year but it is worth it to have a 4 ft. tall plant covered with blooms.

Now THAT's a vine to die for! :)

suetran1(7NC) Mandevilla x amoena/Apolynaceae: Hi I love your flower. I have seen only single flower and the color is not as bright as yours. Could you kindly share the seeds with me? I am an avid gardener and I collect rare flowers. Thank you.