I live in a small urban rowhouse with limited outdoor space. Thanks to a major renovation project I finally got my dream of a rooftop deck a little over a year ago. Last year was my first time attempting to garden up there and I'll be the first to admit I went a little bit nuts! Having a water source is absolutely critical. If there's no hose or spigot on the roof, watering will be a major pain in the @$$--and either way, the more plants, the more time watering so fewer plants in bigger pots make a big difference. Small pots will dry out far too quickly. Likewise, clay pots will dry out very quickly; use plastic pots to help minimize watering. Surprisingly, I didn't find much difference among the various potting soils I tried--plants did well in all of them, as long as I factored in (1) how wet or dry the plants wanted to be and (2) how quickly the particular mix drained. Lightweight soil mixes dry out very quickly, however. One thing that did surprise me was how much the water run-off stained our deck. One of the potting mixes (Gardener's Gold) was rather heavy and high in organic matter--great for the cannas and other tropicals but the water that ran out the bottom was dark brown and left stains. To minimize damage to a deck, perch the pots on "feet". One thing I didn't factor in was what to do when traveling; in early summer when the plants were small I could leave them for 2-3 days but by the end of summer even one day without watering would have been a disaster. Make friends with your plant-loving neighbors so they can water for you when you travel! Seek out sun, wind & drought resistant plants. On my ground-floor deck--as hot and sunny but not as windy--I grow many plants in containers, including herbs (mostly basil) in big pots with angelonia, a great combination that looks good right up until frost. Many grasses are suitable for exposed locations and on the rooftop deck, Pennisetum setaceum 'Rubrum' did particularly well. I was also very pleased with Gaura, which bloomed all summer. Although I didn't try any succulents, I expect sedums, portulacas and many others would do well. Cannas did surprisingly well, even once they became hopelessly potbound, but by late summer they required watering twice a day. Deep saucers to hold water helped a bit (but not as much as I hoped!). The good news was that drying out a bit didn't seem to hurt them much. Some plants loved the sun and heat but were difficult to keep watered properly--this included ornamental sweet potatoes and elephant ears. I had to keep cutting back the sweet potatoes so they wouldn't take over. Some plants did well but were ultimately so messy I won't grow them again. This included salvias and lantanas; hundreds of little flowers kept dropping all over the place and I had to keep sweeping them up. This year, I plan to grow fewer plants; I will grow the grasses and cannas again, but no lantanas or salvias (although I will miss the hummingbirds they attracted!). I will also grow plants mostly in their own pots--no more mixed containers because almost invariably, one plant would do better than the rest and crowd the other plants out. Finally, make sure you have (1) a place to sit and enjoy it, and (2) some kind of shade. These are little things but will make the rooftop so much more enjoyable. Here's a slide show documenting my rooftop deck and the plants I grew there in 2009, along with a few photos of my ground-level garden (as viewed from the deck) mixed in. Here is a link that might be useful: Rooftop deck slideshow

I can't speak for Ohio..But here in Milwaukee, WI we're a zone 5. We have cold wet winters and avge rainfall in summer. The best is to raise your bed. That will help immensely. Also a nice gravel mulch is good also. I, personally, do not cover anything. Some leaves do float in and I have learned to not be so meticulous in my fall cleanup. I think it has helped some things like Delospermas come through the winters. If you feel the need to cover anything I would not do the whole bed. Make a tent of some plastic sheeting and just lay it over the individual plants like a pup tent (weighted down on opposite sides and left open on the other ends for ventilation). Just my 2 cents worth, and what works for me may not work for everybody. Dave Milwaukee

A couple of general comments: Sigrid’s comment about snow sliding off the roof casing damage is on the mark if your mom’s roof is aimed to dump snow on this area. My plantings under eaves are either perennials or shrubs that either tolerate snow getting dumped on them when we have to rake the roof after really heavy snow, or ones that I can cut to ground level in spring if there is damage and they will regrow quickly. You will want some evergreens, either conifers or broadleafed. Otherwise even with the berries, dried hydrangea flowers, and red stems this area will look stark in winter. Consider adding evergreen groundcovers under the shrubs as well for times when there isn’t snow. I don’t grow any of those particular cultivars, but grow other cultivars of all those plants. Several of them I wouldn’t consider of multiple seasons of interest. There are comments on Bobo on both the perennials forum and the Hydrangea forum. It has a long season of bloom (4 months here), and some H. Paniculata varieties have some fall color. I like leaving the dried blossoms on for added winter interest. Bobo on Perennials Forum. Bobo in Hydrangeas Forum Winterberry is a holly which like all hollies have separate sexed shrubs. So in order to get berries, you need a male that blooms at a compatible time to pollinate Berry Poppins; in this case Mr. Poppins is marketed for that purpose. My Winter Red suckers energetically, but I don’t know if BP does. I love winterberry but its only real season of interest is fall since the berries ar often eaten by birds in winter. Pollinators love winterberry holly so it does have summer value, but it is fairly unobtrusive during the growing season as far as human ornamental value. Clethra is interesting when it blooms for a couple of weeks in August here and then my Ruby Spice has lovely yellow autumn foliage. Just a green mound in spring and summer and a twiggy mound in winter. Cornus Arctic Fire has autumn color and red winter twigs, but all the nonvariegated Cornus shrubs in my experience are just green mounds for most of the growing season. I have yet to see one that I would value the flowers or berries as ornamental, though this one may be different. It suckers, and to get the bright red winter twigs, older branches need to be cut out periodically. Koren spice Viburnum has heavenly scented spring flowers that waft the scent well, and some cultivars have nice fall color which Spice Girl is said to have. It will also spend the summer as a green mound. Most Viburnums need a different cultivar (or a wild type) to have fruit as most aren’t self-compatible.

Two very different styles so maybe think what style you want . Skillion roofs generally are a more contemporary style . As for longevity that depends on your style again. I happen to like them but I also like contemporary design so no gables for me.Heating and cooloing are always issues with high ceilings but can bea ddressed when building to minimize that problem