Culture
Best grown in medium moisture, slightly acidic, well-drained garden loams in full sun. Tolerates some light shade, but best flowering and disease resistance generally occur in full sun. Water deeply and regularly (mornings are best). Avoid overhead watering. Good air circulation promotes vigorous and healthy growth and helps control foliar diseases. Summer mulch helps retain moisture, keeps roots cool and discourages weeds. Remove spent flowers to encourage rebloom. Crowns may need some winter protection in cold winter climates such as the St. Louis area. Remove and destroy diseased leaves from plants, as practicable, and clean up and destroy dead leaves from the ground around the plants both during the growing season and as part of a thorough cleanup during winter (dormant season). Hybrid tea, floribunda and grandiflora roses in St. Louis are usually pruned back to 12-18” from the ground in late winter.
Noteworthy Characteristics
Rosa is a genus of about 150 species of deciduous (occasionally evergreen) shrubs and climbers noted for their beautiful, often fragrant, single, semidouble or double flowers which are borne singly or in clusters on often prickly stems clad with 5-9 leaflets often having toothed margins.
Hybrid tea, floribunda and grandiflora roses are the classic florist-type roses. Hybrid tea roses have high centers, long stems and usually produce just one terminal flower per shoot. Floribundas produce clusters of flowers and grandifloras produce clusters of high-centered flowers. These roses require regular, severe pruning to maintain size and produce the long-stemmed blooms they are known for.
Genus name comes from the Latin name for rose.
'Gruss an Aachen' is a vigorous, compact, bushy, rounded shrub which typically grows 2' tall with a slightly larger spread. Features clusters of fragrant, double flowers (to 3" across) which open salmon-pink and mature to creamy white. Blooms in May with good repeat bloom throughout the summer. Small, dark green foliage. Few thorns.
Problems
Roses are susceptible to a large number of diseases, the most common of which are black spot, powdery mildew, rust and rose rosette. Although good cultural practices are the first line of defense in disease control, regular preventative fungicide applications throughout the growing season are usually required, particularly in humid climates with regular rainfall such as the St. Louis area. Potential insect problems include aphids, beetles, borers, scale, thrips, rose midges, leafhoppers and spider mites. Local rose associations and extension services are usually able to offer specific recommendations and advice for selecting and growing roses.
Uses
Shrub or mixed border fronts. Wild, cottage or rose garden. Also effective as a low hedge or edger.