Gallica - One of a group of Old roses predating the introduction of China Roses into rose breeding and characterized by highly stylized, formal blossoms. The flowers range from purplish and crimson tones through light pinks. The are usually fragrant, but are produced but once a year. Gallicas are cold-hardy and disease-resistant.
Grafted - Grafting is the practice of attaching one branches or parts of one cultivar to the roots or trunk of another plant. In Rose culture it is typical to insert a small bit of stem cell tissue, a bud, into a developed root. Such roses are called 'budded.' The practice arose because it made propagation of many cultivars possible where is was before impossible due to weak growth of the roots. It can also speed propagation when one is in a hurry to rush a newly patented rose to market before the patent expires.
Controversy has swirled around the practice for years. The upshot is: some roses are better suited to be propagated by budding. Some do just as well on their own roots. Some roses last well when budded. In other cases there are complaints that the bud union gets infections or has other weaknesses not generally found in own-root stock. Most rose buyers trust their suppliers to make good choices in this area. If a rose is offered on own root stock it might, sometimes be a little slower starting out. But it might also settle in and last longer.
Damask - One of a group of Old Roses predating the introduction of China Roses into rose breeding. The roses tend to be less formal than Gallicas and come in fewer colors -mostly pinks, and they tend to be more consistently and deliciously fragrant. They bloom once a year and are tough, hardy, and disease-resistant. The group includes Ispahan, Marie Louise, Madame Hardy, and Celsiana.
Deadhead - To remove the spent flowers from a rose (to prevent hip formation.) This encourages the rose to continue producing flowers.
Diploid - Having two times the haploid number of chromosomes. If, for example, the haploid number is 7, then a diploid organism would have 14 chromosomes. China roses are diploid, but most other roses are tetraploid. A small number of species are hexaploid or even octaploid having 3 or 4 times the number of chromosomes as China roses.
Downy Mildew - A fungal infection of rose leaflets that turns the surface dark purple or black. It is distinguished from black spot by the fact that the leaves do not turn yellow and fall from the plant quite so readily as they do with black spot. And while the spots in black spot are almost always circular, downey mildew tends to form large splotches whose shape relates somewhat to leaf features. Cool damp nights encourage its growth. Centifolias seem to be particularly affected by it.
Floribunda - One of a class of roses that bears flowers in clusters, usually reblooming over and over throughout the season. See Cluster-Flowered above.