Growing Roses From Seed
by David Alosi, U.C. Master Gardener
 Rose Hips & Seeds |
Roses are not difficult to grow from seed if you do it right. It may take a little while for the seeds to sprout and the plants to bloom, but with a little patience, you will end up with roses that no one else in the world has.
If you plant seeds of 'Just Joey,' you will get climbers, large bushes and small bushes, in a variety of colors, but you will not get another 'Just Joey.' This is the case with every variety; roses don't "come true" to the original type. No matter which rose you start with, you probably won't produce any offspring that will take the rose world by storm, but you will likely get at least a few interesting plants worth keeping.
Rose seeds develop inside the hips, the fruit of the rose. If you deadhead all your roses, you will not get any hips so refrain from deadheading some blossoms. When you plant seed you have collected from hips, you can be certain of the identity only of the female parent. Making your own crosses by choosing both parents of your seeds and hand pollinating is also possible, but that is more complicated and will be the subject of a future article.
Unfortunately, not all roses are good mothers. Look for roses that set a lot of large hips, and leave some of these hips on the plants all summer.
In the late summer or fall, collect hips that have ripened. They'll usually be yellow, orange, or red. Cut them open with a knife, and dig out the creamy white seeds. These are the "achenes," in botanical terms. Each achene has the true seed inside, but for practical purposes, we can think of achenes as seeds.
Most roses originally came from colder climates, and their seeds need to survive a winter before they sprout. We can trick them into sprouting by giving them a stratification treatment—a period of moist, cold storage.
Rinse the seeds of any fruit pulp and plant them about one-quarter inch deep in a seed-planting mix. I use a mixture of one-third perlite, one-third vermiculite and one-third peat moss. I like to use the clear plastic cherry tomato or strawberry cartons, and I plant multiple seeds per container. Seal each container in a plastic bag and refrigerate. Be sure to label each container, indicating the parent variety and the seed-planting date.
After eight to twelve weeks, bring the containers out into a warm environment (about 70ºF). I like to time this for early spring, when seeds are normally waking up and sprouting. As your seeds sprout, carefully transplant the seedlings to other pots with a small spoon or the end of a plant label. Don't touch the roots during this process. Feed the seedlings with half-strength fertilizer and give them lots of light when they start to grow.
After several weeks, put containers with any unsprouted seeds back in the refrigerator for another month, then try them again in the warm environment. Depending on the variety, seeds may continue to sprout over several months, but don't expect more than thirty percent of the seeds to sprout overall.
Young rose seedlings are susceptible to damping off, a disease in which the stem rots at the soil surface. To minimize damping off, use a sterile planting soil, don't overwater and, if you like, use a fungicide right after the plants come up. Provide good air circulation and lots of light.
Some of your rose seedlings may also develop powdery mildew. It is probably best to discard those plants, since they are not likely to develop resistance later in life. Keep the robust, healthy seedlings instead.
If your seeds' parents were both repeat-flowering varieties, the seedlings may flower in as little as five or six weeks after planting. Most will send up a long stem and flower in the first season. If either parent was a once-flowering rose, however, the seedlings may not flower the first year. Some may take three years or more to flower for the first time, but with a little patience, you will eventually be a proud parent.