Can you fertilize miniature roses as soon as you plant them with a blossom booster, or should I wait for a couple of weeks? Also, what would help them flourish better at first?
Definitely hold off on any blossom booster fertilizers. In some cases I am not sure why they call them blossom boosters as their Nitrogen content is very high and that can lead to extreme foliage growth and limited to no blooms. ??? I would water in the new miniature roses with some water that has both a good root stimulator and a product called Super Thrive mixed into the same water. Give them this mix the next 3 to 4 times they need watering. It helps get the roots going well and the super thrive has vitamins and hormones in it that help the roses deal with transplant shock and any other stresses they are dealing with for optimum performance. Once they start forming new buds, give them a little organic or organic based rose food. Giving them a little kelp meal in three weeks after planting will be good too. Check the growth habits of the miniature roses you have too. Some can get pretty big as the word miniature refers to the size of the bloom and not necessarily the size of the bush itself.