From a door function standpoint, leave 4" minimum from the corner. This gives you enough space so that the door can open 90 degrees without having the door lever hit the wall. 6" is also common too. You don't want to leave too much space or you are just wasting usable wall and floor space in your room. However, from a maintenance and aesthetic standpoint do head bpath's advice above. The trim should either leave at least 3/4" to 1" wall reveal from the corner or be right up against the adjacent wall. leaving a small space is going to result in an awkward strip of wall color and will be difficult to maintain going forward. In our current house we have a few of these conditions where it is tight between the casing and corner. The last owner wallpapered and we have had extreme difficulty getting old wallpaper out of these corners. In some cases the trim had to be taken off to get good paint and stain coverage on them too.

I agree with M Miller. 18" is standard and manufacturers of small appliances use that standard to design their appliances. Another thing to factor in -- light rail. If you plan light rail, you might want to consider 18" + the height of your light rail. That way, taller small appliances will still fit. I wish we had done that. We planned for 18", not realizing the light rail would take away from our usable height. (No, our KD did not mention it.) My KA stand mixer (bowl lift) actually brushes the light rail when I slide it in/out from under the cabinets. I have a cover for it and I have to take the cover off b/f I can slide it past the light rail.

For trees, which have large trunks that intercept water, that water runs right down the trunk. So much that mulch that is "volcanoed" under the trunk can get especially wet. For smaller plants with narrower stems, this isn't an issue. After a rainstorm, some of the wettest places on the ground are right around the trunk of a tree. Not good to have material there that collects that water. Also worth noting that fine textured mulch, such as peat moss, grass clippings, and sawdust hold water much better than coarser mulches. These mulches can be especially damaging in close proximity to plants.

How long are you planning on keeping these roses in containers? Will you ever be able to plant them in the ground? If you plan on leaving them in pots for years, I would not use 20 gallon black plastic pots - you could cook them in full sun in a hot climate. Since you just got these roses, and just planted them in 4 gallon containers, I would leave them alone (with lots of water as everyone says) for at least 6 months. They need to recuperate from being transplanted, and need to be left in peace to grow some roots. If they were mine, I would leave them alone for 6 months, or until I saw roots growing out of the bottom of the containers. If I then wanted to transplant them again into a bigger container where they would have to stay for years, I would get a non-glazed normal clay colored CLAY container, and it would be way bigger than 20 gallons - maybe 40 or 50. If, on the other hand, you will be able to plant the roses in the ground, a 20 gallon plastic pot would probably be OK for another year or so until you can put them in the ground, but not black. Drainage - I do not put any of the pots my potted roses are in directly on the ground, cement, etc. There are many things you can buy to put under the pots (from cheap to expensive) to help them drain. I try to keep my pots up on these sort of things at least 1 1/2 inches above whatever surface they are on. Glad your roses perked up when you gave them more water. That is how we all learn about roses on here - asking for advice, and then seeing what works! Good luck, and keep us advised about how you do with these roses. Jackie