Hello,

We purchased a house over the summer and these plants are outside next to the fence. What do I do with these over the fall/winter - do I move them inside to the garage? Or inside the house? Do they need be watered or do they go dormant?

Hope this helps:

"Mandevilla are not hardy in our area, USDA Zone 6, so you have two options if you would like to over-winter your vine. The first option is to bring it into your home. If you have enough space and a bright sunny window then move the container inside once the weather starts to cool down.

MandevillaIt is always a good idea to prune it back before you transfer it into your home. Cut the vine back so that it is a comfortable size for your home–by half is fine–less or more will also work. It will grow slowly during the winter months. You do not need to encourage growth at this time of year by fertilizing the plant, just water it when it begins to dry out.

Sometime in February, give the plant another good pruning and begin to fertilize it once a month. Mandevilla flowers on new growth. By pruning and fertilizing the plant, you are working to give it an early start so that when you place it outside in May or June it will take off and soon be covered with flowers. If you are growing a mandevilla in your home, it is a good idea to lower your thermostat to somewhere in the 60s or low 70s, otherwise it may get too dry."

Our winters here in the deep south aren't as cold as the ones you northerners have, & I've never had a mandevilla.....but I think if you aren't bringing them indoors for the winter, maybe wrap bubble wrap around the pots (no plastic should touch the actual any part of the plant). I've done something similar with pots I couldn't bring indoors or small trees or shrubs bought months before winter but too small for me to feel comfortable leaving them unprotected. I surrounded the ones planted in the ground with fencing held up & away from the tree/shrub. Then I dumped pine straw & leaves all around to insulate.

Some ideas:

I have overwintered my dipladenia/ mandevilla for 4 consecutive winters (zone 3) The first year I kept it in my attached insulated garage which stays about 50 F; it went dormant and lost all its leaves. In the spring when it started to leaf out I began watering slowly until the days got warmer and increased the watering to support more new foliage. Once the weather was warm and reliable it went outdoors for the summer. It bloomed but quite late in the season. After that I found a place right in front of a south facing patio door and it bloomed until about December and sporadically over the winter.
Since then I have brought it indoors to that same sunny window and it has done very well. It still didn't bloom for me untill quite late in the season but I didn't cut it back as @pirl suggested so I think I will try that this spring to try to encourage earlier bloom.
I'm assuming Minneapolis is about zone 5 or 6? It will not survive remaining outdoors.
Hope this helps! They are beautiful plants and well worth saving.

Mandevilla have to be brought inside as pirl described, they are from tropical and subtropical climates. I'm in 9a and lost mine to frost.

Another option... A neighbor here in Texas loved pink Mandevillas (there were no red cultivars at the time). She tried growing them outside, inside and she finally decided to get a new plant every spring instead. The advantage was that the new plants were already large enough for her and blooming. Overwintering Mandevilla produced plants that would slowly leaf out and bloom later than she wanted. The disadvantage was the re-occurring cost.

Thank you for all your responses! I will prune the plants and move them inside for the winter.