| Was just going to tell you : "DO NOT" fertilize a newly planted rose" and then I saw that diane_nj was suggesting the same. You might have leaf burn. I have just written an article for my web-site about planting and growing minis. It will be edited and then added to my articles page within a month.
Here the unedited version : Tips for planting and growing Miniature Roses # 1 : When buying NEW minis, which come out of the greenhouse. "Do not" expose them to direct sunlight right away as you may burn the foliage.
Keep in the shade for at least a week and then gradually give them 2 to 3 hrs of sun a day for a week to 10 days. Then you can put them in "FULL" sun. # 2 : Planting. (Canada and northern US States)
When you buy a new mini in a 3 to 4 inch pot, do not plant them into the ground right away !!! If those small pots are full of new roots, I cut appr. 1/4 inch off the bottom of the root ball with a steak knife. This way new fine hair roots will develop really fast. I first transplant mine into one gallon pots. After 3 to 4 months the one gall. pot may have roots right down to the bottom. If roots go around in circles it’s time to plant into 2 gall. pots. Again, I cut about 1/2 inch off the bottom with a large steak knife. From the 1 gall. one could plant them into the ground, but I prefer to leave them in the 2 gallon pots for the first season. Years ago I did some experiments with my own minis and those I grew on in pots were 2 to 3 times larger after one season compared to those which were planted right into the ground.
Up north the ground never warms up until late May compared to the pots where the soil warms up fast with just a few hrs. of sun a day.
In the southern & hot US states it will be OK to plant right into the ground. # 3 : Fertilizing. "DO NOT" use chemical fertilizer for potted roses !!!
My friend Tony and I have both killed a number of minis in one and two gallon pots, using the fertilizer we use in the rose beds. Too much nitrogen will damage or kill the roots and the plants may die. Use slow release Osmocote.
Or, water soluble fertilizer can also be used. If it calls for a teaspoon for 4 litres or 1 gall. of water use a level spoon, but "NEVER" a heaped one. As this is also a chemical, use a bit less as too much may damage the roots but may not kill the plant. Again I am speaking of my own experience. # 4 : Needless to say, water, water, water !!!
Never let your pots dry out as they have to be watered more often than roses in the ground.
Good luck George Mander | 
