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.
The easiest way to begin experimenting with rose hybridizing, especially for the beginner, is to simply let some of your roses self-pollinate themselves, so they will "go to seed" and set hips. I have found that Playboy, Hurdy Gurdy, Peggy T and Fairhope are some of the easiest roses to set hips, and there are many others. Let the rose hips stay on the rose bushes at least four months before harvesting.
To get the best success, yor rose seed will need a period of stratification (a cold period of about 6-12 weeks). Its a good idea to time this so that it coincides with when they would naturally start to grow in spring – probably around early March, depending on weather conditions. I would look to sowing them in late November/ December and popping them outdoors or if we have a mild winter then stick them in the fridge!
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.
Remember that light changes as the angle of the sun shifts throughout the season. If you live in the upper half of the U.S., choose a site that will offer full sun year-round. The more sun you have, the more flowers your plants will produce. In the lower half of the U.S., choose spots with a little bit of afternoon shade. This protects blossoms from the scorching sun and helps your flowers last longer.
I received some seeds as birthday present, the seller included a bonus packet of rose seeds. There’s no indication if they’ve been stratified. If I stratify them now, it will be July when they’re ready to plant. In this region (I’m ~50 miles north of Portland, Oregon)it might be mild or very hot. I’ve read that rose seed won’t sprout if it’s too hot – how well do rose seeds keep? Will they still be viable next Spring, or should i take a chance on the weather and start them now?