Fertilizer: Roses are heavy feeders, and will benefit from a steady supply of nitrogen, phosphorus and potassium. You can provide these nutrients with either liquid or granular fertilizers, at a ratio of approximately 5-8-5. In most cases, regular applications of compost, rotted manure, fish emulsion and seaweed extracts will provide roses with all the nutrients they need. These organic amendments also help to moderate pH imbalances and stimulate beneficial soil life. Other organic amendments favored by rose growers include greensand, black rock phosphate and alfalfa meal.
When pruning, be judicious. If you prune too hard in autumn, plants can be damaged beyond recovery. Instead, wait until spring, when plants begin to leaf out for the new season. (Roses are often not the earliest plants in the garden to respond to spring’s warming temperatures, so be patient.) Give the plant time to show its leaf buds then prune above that level.
Prepare a large hole. You'll need one for each rose bush you're planting. Use a garden spade or shovel to dig a hole 18 inches (45.7 cm) wide and 18 inches (45.7 cm) deep. The measurements don't have to be exact, but a hole this wide and deep will be suitable for most roses. Mix the soil you removed from the hole with compost, and use some of it to form a small mound in the base of the hole. Add some bonemeal or rose fertilizer.
So grandma had the right idea in the first place, and she really did know what she was doing. It has always been fun to start roses from cuttings. Some people get their kicks by going "rose rustling" in the deserted cemeteries of old and forgotten mining towns. Others just take a twig from their favorite rose and stick it into the ground in their backyard. There is nothing complicated nor scientific about taking cuttings of roses and rooting them to "start" a new plant. There are various ways of taking rose cuttings, so let's tell you how.
Grandma's Mason Jar: For the beginner this is probably the easiest way to take rose cuttings. Not much equipment is needed, just a clear quart-size glass jar and some cuttings from your favorite rose. For you modern sodapop lovers, a 2-liter plastic bottle with the bottom cut off will work just as well. Cut a piece of rose stem about 6 inches long, remove the bottom set of leaves, and just stick the stem into the ground (or into a pot) a couple inches deep, and cover with a jar or bottle. You will need to periodically water the soil around the jar, otherwise the rose stem will dry out. It will take a couple of months for the rose stem to take root and begin leafing out with its new growth. The best time of year is spring or early fall. If you live in a mild climate, then winter and summer can also be successful for rooting roses. Intense summer heat of 100 degrees is not conducive for taking rose cuttings, nor are 32 degree or below winters.
Cover the cutting loosely, pot and all, with a plastic bag or plastic wrap and keep the soil moist. Putting a tall stake into the pot will hold the plastic away from the leaves. If the plastic touches the leaves, they remain wet and can succumb to a fungus disease. Along the same lines, make sure the condensation can escape from the plastic or the stem will rot.