Gardening and Horticulture - Planter for Rose bushes

I am converting my garage to a bedroom and have a concrete walk running in front of it about 4 feet out. I have to raise this up to prevent flooding under my house and plan to do so about 4 inches up from the existing walk and then close the wall off where the garage opening is. I would like to then build some type of planter like brick, concrete or even landscape timbers and plant roses to grow under the new windows. My question is, when I build this thing no matter how I do it there will be a concrete bottom and I am worried about what it will do to the soil. Will I need to add drainage to it or replace the soil every few years? I figure the planter would be about 2 foot high to get it closer to the windows. If it matters I am in centtral Oklahoma.

So long as what you build will have drain holes to keep it from becoming a swamp, you should have no trouble in the long run. I would equip it as if it were a large flower pot: Gravel at the bottom for drainage, then soil.

Hope this helps.

Ok, thanks. Thought I would need to but wasn't sure.