Nursery Care Sheets

Roses

Rose gardening has the reputation of being difficult, time consuming, and a hassle. However, with the right information and the proper rose selection, it can be a fun and enjoyable way to improve a landscape.

Tips for Success
ROSES PREFER TO BE PLANTED IN WELL-DRAINED SOIL. Soil that does not drain well keeps the roots surrounded in water, depriving them of oxygen. This essentially drowns the plants roots making them incapable of serving the plants needs.

PROVIDE THE ROSE WITH AT LEAST 6 HOURS OF SUNLIGHT PER DAY. Sunlight is necessary for the rose to set buds, without ample light the rose would have fewer flowers as well as the potential to suffer from disease problems. The sunlight aides in evaporating moisture off the leaves which if left there would provide ideal conditions for fungal disease.

AVOID EXCESSIVE MOISTURE. The importance of keeping moisture levels down is twofold. Maintaining good air circulation will reduce the amount of moisture that accumulates on the plant and keeps disease incidence down. When watering, water only around the base of the plant, where water will not come in direct contact with the leaves. The watering schedule would be determined by the soils capacity to hold moisture at a reasonable level, therefore, checking the soils moisture often is best.

Rose Selection

There are many types of roses to choose from. Roses are divided into the following classes based on certain characteristics and growth habits. Reading about the different types will help with the selection process and knowing what to expect.

SHRUB ROSE - This group contains roses grown on their own roots, that is not grafted, and known for their superior winter hardiness and disease resistance. Many collections of roses are encompassed by the term shrub rose. Buck roses, the Explorer Series, and Easy Elegance to name a few. These types are more resistant to black spot and powdery mildew. Familiar shrub roses include ‘Knock Out’ and ‘Bonica’.

HYBRID TEA ROSE - The traditional cut flower rose. Flowers are borne on long stems and are available in most colors. These roses are grafted and can be more susceptible to black spot and powdery mildew. These roses need protection over the winter in this climate.

POLYANTHA ROSE - Characterized by large clusters of small flowers. Derived from Multiflora and Chinese roses. Familiar polyantha roses include ‘The Fairy’ and ‘Cecile Brunner’.

FLORIBUNDA ROSE - Cross between hybrid tea and polyantha roses offering a compact, disease resistant plant with large variety of colors. Produces large clusters of small flowers. Some familiar floribunda roses include ‘Chuckles’ and ‘Nearly Wild’.

GRANDIFLORA ROSE - Cross between Hybrid tea and floribunda roses offering a large variety of colors. Known for their vigor and high flower production. Often taller plants that carry their flowers near the tops of stems. Familiar grandiflora roses include ‘Hi Neighbor’ and ‘Pink Parfait’.

RUGOSA ROSE - An extraordinarily hardy, salt tolerant rose. Highly fragrant flowers varying in color from mauve to white. Familiar rugosa roses include ‘Topaz Jewel’ and ‘Grootendorst Supreme’.

CLIMBING ROSE - Roses do not technically “climb” by sending out suckers, but rather they grow on very long canes. They require attachment to arbors trellises or other structures. Familiar climbing roses include ‘Ramblin Red’ and ‘William Baffin’

MINATURE ROSE - Often sold to be grown in containers or as annuals, as the flowers are extremely small and if not a prolific bloomer, they get lost in the landscape.

Common Pests & Diseases

BLACK SPOT - A fungal disease that appears as small black spots on the lower leaves of the plant and can also affect the petals by discoloration. Severely affected leaves turn yellow and fall off. Cultural controls include providing good air circulation, ample sunlight, and removing leaves and debris from around the plant, where the fungus over-winters. Black spot may be more common in years of higher humidity or abundant rainfall. Chemical fungal control is quite effective, but often unnecessary given good cultural practice.

POWDERY MILDEW - A fungal disease that appears as a film of white powder on leaf surfaces, or at the base of flower buds. Leaves can curl and crisp, while buds may bend and fall off. The mildew absorbs the fluid out of the plant weakening it. This is more common in late summer when day are hot and humid. Cultural practices are the same as with black spot, however, fungicides are also available for treatment.

APHIDS - Small soft-bodied insects found clustered around buds and tender new growth. They can be lime-green, black, or white in color. The aphid excretes a sticky, sugary substance known as honeydew as a result of sucking the fluid out of the plant. The presence of this substance on the leaves strongly indicates the presence of aphids. Aphids are easy to control with mild insecticides, a mixture of soap and water, or even by spraying the plant with a hard stream of water.

Pruning

Roses flower on new growth, so they can be safely pruned in spring or fall without jeopardizing flowering. However, heavy pruning should be done in early spring allowing the shrub to fill out again over summer. Shrubs can be reduced to five or seven strong canes by removing old and dead canes at this time. Healthy, live canes will be dull green in color, not brown, or grey. When removing spent flowers, prune to the first five-leaflet leaf or the most vigorous bud. This is good to remember when deadheading roses that flower in clusters. In preparation for winter, roses can be pruned back slightly to ease the removal of leaves and garden debris, but save heavy pruning for spring. It is a good idea to disinfect your pruners with rubbing alcohol between pruning on different plants to prevent the spread of any potential diseases.

Overwintering

To over-winter grafted roses, mound six to eight inches of fine compost or soil over the graft union, where the rootstock meets the canes. Rose collars work well to preserve the mound. The compost freezes around the graft, protecting it from temperatures below 32° F and preventing repeated freezing and thawing of the graft. These methods can also be used on non-grafted roses in preventing rabbit damage over the winter.