Black Spot: Rose plant leaves with black spots that eventually turn yellow have black spot. This is often caused by water splashing on leaves, especially in rainy weather. Leaves may require a protective fungicide coating, which would start in the summer before leaf spots started until first frost. Thoroughly clean up debris in the fall, and prune out all diseased canes.
The Misting Method: As you get more sophisticated in your rose propagating methods you may eventually want to set up a misting bench. It can be an open-air bench or one enclosed in a greenhouse, or even a small misting box, similar to the one my husband Bob built for me. (Refer to "How We Made Our Misting Box," from Rose Ecstasy. You could choose to rig it up with a manual or an automatically-timed mister, whatever your time, money, or expertise will allow. I am fortunate to have a very handy guy for a husband, who is a good sport whenever I come up with these crazy project ideas.
Plant the rose bush seeds approximately ¼ inch deep in a seed-planting mix in seedling trays or your own planting trays. The trays need not be more than 3 to 4 inches deep for this use. When planting rose seeds from various rose bush hips, I use a separate tray for each different group of seeds and label the trays with that rose bushes name and planting date.
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.
It is generally agreed that "old roses" include species or wild roses; albas; Bourbons; moss roses; China roses; Noisettes; Portland roses; rugosa roses; Scotch roses; centifolias; hybrid pimpinellifolias; damasks; gallicas; hybrid perpetuals; tea roses; and musk roses. Those classified as modern rose varieties are hybrid teas; floribundas; polyanthas; grandifloras; miniatures and dwarfs; modern shrub and landscape roses; climbers and ramblers; and rugosa hybrids.
Allow rose hips to develop by leaving dead flowers on the plant. The flowers are typically pollinated by insects, or pollinate themselves in some varieties, so there is no need to pollinate by hand unless you are breeding specific plants together. Leave the flowers on the rose plant without cutting them. After they wither, small fruits known as rose hips will develop in their place.
Select two roses that you want to cross-pollenate. The blooms should not be too tight, perhaps about one-half to 3/4 open. Carefully peel off all the petals. The rose stamens inside should look golden yellow and fresh. With sterile tweezers or cuticle scissors, carefully remove all the stamens at the base of the rose hip, so you do not damage the pollen sacs (anthers). Place the rose stamens into separate, clean film canisters, and place the canisters in a dry place, but not in direct sunlight.
Next fill your trays or pots with the potting soil. You can opt to use 50% sterile potting soil and 50% vermiculite, or half peat and half perlite. When the potting mix is ready in the trays or pots, this is the time to take off your seeds from the towel. Remember the seeds must not be removed from the plastic bag until they are ready to be planted. You lightly dust them before planting.
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.
Prune the roses. Pruning roses keeps them both beautiful and healthy. The goal is to clear away crowded areas to open up the bush, which helps prevent rotting and disease. The pruning strategy differs according to the season, but the cut you make is always the same: prune just above a bud eyes, the areas where branches form. They look like small circular swells and are usually located above a set of mature leaves. Make a down-slanted cut on an outward-facing bud eye.
Place a jar over each cutting to form a sort of miniature greenhouse for each cutting. It is extremely important that the soil moisture for the cuttings does not dry out at this rooting time. The jar will help to hold humidity in, but can be a problem if it is subjected to a lot of hot afternoon sun, as it will overheat the cutting and kill it, thus the need for shielding against the exposure to the hot afternoon sun when you root roses. Watering of the planting site every other day may be required to keep the soil moist but do not create a standing water or muddy soils situation.
Caring for rose bushes is important to their overall health and vigor, especially when it comes to watering. Roses require at least an inch of water weekly throughout their growing season, beginning in spring or following spring planting. While overhead watering is suitable before the onset of new growth, it is often better to water these plants at the soil line using soaker hoses or similar means. Rose bushes are very susceptible to fungal diseases, such as black spot and powdery mildew, especially when their foliage is kept too wet.
If you order bare-root roses from a mail-order company, order early (late winter or early spring). The roses are usually shipped in the spring because bare roots when plants are fully dormant, well before they have leafed out. They’ll look like a bundle of sticks on arrival. Note that they are not dead—simply dormant. Check that the packing material is moist and keep them in a cool dark place until ready to plant.
NOTE: During my move, I had cut several rose branches and placed them in a grocery paper bag in my garage--only to have forgotten to bring them home for a week. The branches had been in a broiling hot enclosed garage without water, and needless to say, they looked pretty dried out to a crisp. But I didn't want to just toss them out yet (these were the climbing Charisma roses), so I got an empty plastic detergent tub and completely immersed the stems for 2 weeks (no changing water). Then I stuck them into soil and hoped for the best. Well, I got about a 50% survival rate.
I have successfully taken rose cuttings with both new and old wood. It is important to let the new stems sufficiently mature. The new wood is usually mature enough after the stem has just finished blooming. If you don't let the stem mature enough, then it usually becomes limp and will die before you can get it to root. I take cuttings from new rose stems in the spring right after the first bloom cycle. Then in early to late fall (in Southern California) I prefer to use more mature or old wood. When using old wood in the fall, I will remove the rose cuttings from the Mason jar, baggie, or mister, after only several weeks since it is cool enough then for them to root on their own as long as I water them daily.
Plant the seeds. Some store-bought seeds can be planted immediately. If you germinated your own seeds as described above, plant them as soon as they begin to sprout. Plant with the sprout pointed downward, as this is the root. Lightly cover them with soil, about 1/4 inch (6 mm) deep. Space seeds at least 2 inches (5 cm) apart to minimize competition.
Everybody has a story to tell of how their grandma would stick a piece of rose stem into the ground and then place a Mason Jar over the stem to make it grow. There are tales of how the early American settlers of the 1800's traveled to the far reaches of the wild west in covered wagons, with grandma bringing along "starts" of her favorite roses from back home. Perhaps the treasures of these "monsters on wooden wheels" were raided, and they discovered the Yellow Rose of Texas hiding under the bonnets of the women. Or maybe the settlers used their precious "starts" to barter for provisions along the endless dusty trails.