Hallson Gardens

I have very large "The Fairy" that was beautiful until I put it in a 21" fiberglass whiskey barrel three days ago. Now, half of the leaves are yellowing. It is planted in a mix of peat moss, perlite, a "smidgen" of potting soil, and mostly finely ground bark mulch. What does it need? Just Miracle Gro? What?

Sorry, but roses hate peatmoss... do you have clay in the garden ?

If you have garden soil with clay, mix it with something to drain a bit and some good compost... and it will be fine next spring.. it is a good one for pots.. big ones as yours
Pia

Peat moss is usually adjusted to a usable (plant friendly) pH range. It should say on the bag. Raw peat moss is pH 3.5-4.5 suitable only for acid lovers like blueberries while bagged peat is pH adjusted from 4.0-5.0 to 6.0-7.0. Roses will only be happy with peat adjusted to pH 6-7.

If your pH is off due to the peat moss the nutrients will be unavailable to the plant. A quick pH test might be a first step in diagnosing your roses problem.
Try these site for an explanation of the effect pH has on nutrient availability in soil.
http://www1.agric.gov.ab.ca/$department ... /agdex6607
http://www.planetnatural.com/site/xdpy/ ... ients.html
http://www.dnagardens.com/what_is_soil_fertility.htm

Did you transplant your rose without disturbing the roots-- taking a large rootball? It would be best to move roses when they are dormant, at that time bare-root will not matter.

I'd not be surprised to see the rose's leaves yellowing after moving it. Doubt it had time to react to the soil Ph already, although that is a concern.

I'm a little concerned about container-grown roses in your climate.

A soil test is a good idea, but perhaps a sprinkling of lime wouldn't hurt. I'd also water in a couple TB of Epsom salts in a gallon or two of water.