This is a fungus called black spot. Left untreated, it can cause all the leaves on your roses to turn yellow and fall off. It will also affect nearby plants, as it spreads by spores. Remove ALL INFECTED material and throw it away or burn it. Do NOT leave it on the ground as this fungus is very hardy. It can survive winter and travels very easily, even after being removed from the affected plant. Spray your plants regularly (bi-weekly) in the growing season with a good fungicide (I like the Bayer products). You can also add a little bit of dish soap and baking soda to a spray bottle with water and spray the entire plant.
Water: Roses require more water than most other landscape plantings, especially during the first year as the plant is getting its roots established. The best way to water your roses is with drip irrigation. It concentrates the water at the root zone where it is needed, and keeps the foliage dry to minimize disease problems. A good, thick layer of organic mulch will help conserve moisture, reduce weeds, and encourage healthy root growth. As the mulch breaks down, it will also add organic matter to the soil.
Cover the stem with plastic or a mason jar. To cover the stem with plastic, insert two eight-inch (20-cm) sticks or wires into the soil on either side of the stem to prop up the plastic. Cover the pot and stem with a clear plastic bag, and affix the bag to the pot with an elastic or twine. With a mason jar, simply place a large mason jar over the stem.
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.
I do not think this works. nut weed inhibits other plant growth. Cyperus rotundus gives off "chemicals" that slow grow of neighboring plants. Parts are edible and was used in ancient times to prevent tooth decay. Can you show a study where this is true? Cinnamon is a good substitute for root hormone products - rub a little ground cinnamon on the cut
Although miniature roses have always been grown on their own roots since the 1950's when they were first introduced, Ralph Moore of Sequoia Nursery in Visalia, CA, near Fresno, offered many of the larger roses on own-root along with his vast selection of minis. His Playgirl floribunda has always been sold by Ralph as own-root cuttings in 4-inch pots, as well as a good assortment of other own-root floribundas and old garden roses. Unfortunately, Mr. Moore is now deceased and his nursery is closed.
When you grow roses from seed, you are essentially developing new varieties of roses. If the rose fruit -- called a hip -- was produced by bee pollination, you don't know what varieties were crossed to get the seeds. Rose breeders hybridize chosen varieties and select for particular traits in resultant seedlings. However, each seedling will be a surprise. Rose seeds have to be collected in the fall, cleaned, and cold-treated before they are planted. Even though the cleaned seeds may look dry, they are not dry inside. If rose seeds are allowed to sit around in the open air and dry up completely, they will not grow.
I bought hybrid tea roses last year. Not long after the first blooms, we moved one because it was interfering with the sprinkler system. It looked unhappy at first, but continued to bloom throughout the season. This year, it does not have so much as one leaf, no new foliage whatsoever, however, there is still green inside the stem towards the base of the cane. Is it done for, or is there a chance it will come back in it's second rear?