Blue Girl roses (perennial genus Rosa) are not actually blue, but rather a pretty combination of silver and lavender. A classic hybrid tea, Blue Girl produces a nice fragrance and large blooms of nearly 5 inches in diameter. The Blue Girl rose does very well in USDA hardiness zones 5 to 10 and its care is no different than caring for other roses in your garden.
Choose a location where your Blue Girl rose will receive at least four hours of sunlight each day and where it will have at least 2 feet of space in which to grow. Clear away any weeds, rocks or other debris.
Create a hole larger than the size of the pot your rose bush is in. For instance, with a 12-inch pot, create a hole 18 inches wide. Make certain the hole is deep enough to cover the crown with 1 inch of soil.
Pour 1/2 cup of bonemeal into the hole along with a handful of compost. Using a garden claw or spade, stir or mix in with the surrounding soil.
Place the rose into the planting hole after carefully removing it from its original pot. Cover the root system and 1 inch of the crown with additional garden soil and pack it firmly. Water the area very well to allow the moisture to reach a depth of 12 to 18 inches. The soil should remain moist to the touch but not drenched.
Continue to care for your Blue Girl by fertilizing and mulching. Apply rose food after every new set of blooms and add new mulch as needed to maintain a thickness of 2 to 4 inches. This will hold in moisture and keep weeds from sprouting.
Prune your Blue Girl roses in early spring just before new buds begin to form using curved edge pruning sheers. Monitor your roses for pest control and spray with insecticides designed to kill aphids, a common enemy of rose bushes. You can also choose natural methods such as adding ladybugs to your garden to eat the aphids as they appear.