Question
QUESTION: I have several large potted perennials ( hibiscus, mandevilla, clematis, delphinium) that were on my deck all summer long.  What must I do so that they will survive the winter?  I have an enclosed porch that is unheated, can I just move them onto that? If so, when? Must they also be wrapped? Do I still water them during the winter?

ANSWER: Mandevilla's are tropical plants, so that one won't winter over  anywhere, but inside your heated home, and needs to be moved inside before it freezes.  The delphinium, clematis, & hibiscus should winter over just fine in the unheated porch, and should be put there, after the frost has put them into a dormant state, after their leaves are dead. And make sure to prune them down to 2-3 inches at that time as well.  The variety of clematis you have, determines when you should prune it, but most clematis don't get pruned until early Spring, or right after it flowers.  So leave it alone until Spring, but you can strip the dead leaves off. The nursery I work for winters over all our left over perennials outside in pots, so they should do just fine in your un-heated porch, as long as you make sure to water them.  Because the root system is still alive and needs moisture throughout the winter to stay alive.  So whenever the top few inches dry out, water them thoroughly.  You can wrap the pots, but it is not necessary, as long as they are not receiving all day direct sunlight, causing the root system to freeze and thaw everyday.  But you can gather all the plants together and surround them with Hay, or fabric to help insulate the root systems, because it is better to be safe then sorry. And it is not necessary to winter them over in the unheated porch, you can put them outside in a protected area, like under a deciduous tree.  So that they still get light and moisture from the snow.  That is how I winter over all my perennials that are in pots. I gather them together and surround and cover up the pots with Hay, under a tree that has lost its leaves, and they do great.  And that way I don't have to worry about watering them in the winter.  But if you don't have an area like that in your yard, then the un-heated porch should do fine, just don't forget to water them.  One other thing, I hope the pots that they are in can withstand the winter, Terra Cotta & other ceramic pots get moisture into them and crack when the watre freezes and expands.  So hopefully, they are planted in plastic pots, or pots that you don't care that much about, in case they crack. Let me know if you have any other questions.

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QUESTION: About the Mandevillas.  They are trellised on my deck railings and up the outside brick wall of my house. How do I remove them to bring them indoors and once inside how do I care for them?  They are still growing and blooming so thank God I am not too late because I do not want to lose these plants and I have alot of them. Any and all information that you can give me on them is extremely welcome.

Answer
You need to carefully un-twine them, don't worry if you break off some branches.  Because you need to prune them back close to the main stems anyway in late winter or early spring. And by doing that you cut back side shoots to within 3 or 4 buds of permanent framework and thin out overcrowded shoots.  And you will need to get a trellis or something that they can can be supported by inside the house.  They need to be in a south or west facing window.  Preferably south because there is where it will receive the most direct sunlight.  Then water them whenever the first few inches of soil are dry.  They will go into a semi-dormant state because of the shorter daylight hours, but they just won't have vigorous new growth, and you don't really want that inside the house anyway.  Don't feed any fertilizer during that time either.  And then you can bring them outside again once all the danger of frost has past, which is around mother's day for us in Zone 5.  You might want to take the broken off branches, and try to root them, by dipping the cuttings into Rootone and then putting them into a really light and fluffy potting mixture and covering with a plastic bag for a couple weeks, those should root as well.  You might just want to take cuttings, if the plant itself is too big to bring inside.  And that way you won't have to get a trellis for inside either, it is up to you.  Let me know if you have anymore questions about cuttings etc.