By Becky Russell, Colorado Master GardenerSM, Colorado State University Cooperative Extension, Denver County
A rose-covered trellis adds grace and beauty to any garden. The climbing roses adapted to our climate require a minimum of care and will reward gardeners year after year with beautiful blooms.
Climbing varieties of hybrid tea roses, grandifloras, and floribundas are not recommended for Colorado. Instead, look for Old Garden Roses, large-flowered climbers, or selections from the Canadian Explorer series developed in Canada. Most of these roses bloom heavily in early summer and may produce flowers sporadically for the rest of the season, but some are repeat bloomers. Refer to the sidebar and to catalogs, books, and web sites for detailed descriptions.
Most roses prefer full sun, six or more hours each day. They like an eastern exposure rather than baking in the hot western afternoon sun. A site offering some wind protection is best. But even in sites without all these ideal conditions many of the climbers will flourish and bloom.
The most important consideration in choosing a location for a climbing rose is to plan enough room for the mature plant. Many of these climbers are big rambling plants. They require a strong structure for support. A trellis, wall, archway, or arbor serves beautifully. As the flexible canes grow, they can be tied to the support structure. The site should be far enough from other trees and shrubs that the plants dont have to compete for water and nutrients. Follow the recommended spacing instructions from the nursery or supplier.
Roses thrive in a light, rich soil like many other ornamental plants. Mix compost or other organic amendments thoroughly in with the soil from the planting hole filling in around the plant. Add enough amendment to the soil to make a 1/3-1/2 ratio. After planting, keep the soil over the root zone mulched with 2-3 inches of grass clippings, wood chips, or hay. The mulch helps keep moisture in and prevents crusting of the topsoil so that water wont run off.
Rose plants are sold in three different waysbareroot, packaged, or container grown. The varieties may be grafted on to other root stock or grown own-root. Own-root roses grow back true to variety if frozen to the ground, but grafted roses will not. If planting a grafted rose, bury the graft union 1-2 inches below the surface to give extra protection.
Bareroot roses in a dormant state come from most mail-order nurseries. They should be immersed in water after arrival at home, but for no longer than 24 hours, and planted as soon as possible. Dig a planting hole large enough to spread the roots out in, about 18 inches in diameter and 12 inches deep. Prepare the soil as outlined above. Bareroot roses can be planted very early in the spring, ideally before mid-April. Protect from cold by mounding soil loosely over the crown. As the weather warms, the soil can be removed.
Container-grown roses are available at local nurseries and may be treated like other container-grown plants. They can be transplanted to the garden any time, but early spring is ideal so they can establish roots before the hot days of summer. When planting container-grown roses, handle the rootball carefully. Tease out any roots winding around the bottom of the container to prevent girdling of the plant
Packaged rose plants are available at large chain stores early in the season. The roots are usually packed in sawdust or another protective material and the plants are boxed or bagged for easy shipping. These plants are inexpensive, but may be stressed from transit and not thrive in the garden. To give them the best chance, buy immediately after they arrive in the store and plant as soon as possible. Treat as outlined above for bareroot roses.
The newly planted rose will require more frequent watering than the established ones, but all roses benefit from regular water. During the first growing season give the plant plenty of water, but dont drown it. Check to see if water is needed by probing 2-3" under the soil near the roots. If the soil is dry there, apply water. If not, wait a day or two. Water can be applied either by overhead sprinkler or by soaking the ground with a hose. If overhead watering, time the application for early in the day so the foliage is dry before nightfall. This will help prevent disease.
More plants are harmed by over-fertilization than too little fertilizer. Select a balanced product, either organic or inorganic. Apply as directed once in spring and again after first bloom. Dont fertilize after mid-August because tender new growth is easily damaged by an early freeze. Do not fertilize a dry plant. Water first and apply fertilizer. Your local garden center would be happy to give advice and CSU Cooperative Extension has advice available on its web site or through the fact sheets that can be requested by calling the office in your county.
Climbers and ramblers do not need pruning unless they have damaged or dead wood. Take out dead or damaged stems early in the spring. These roses may be lightly trimmed to keep them in bounds, but it is best to plan a site where they can grow free. If necessary, prune for shape after the first bloom because the first blooms of spring are borne on year-old canes.
Pests and Diseases
Colorados dry climate is not conducive to fungal diseases. Rose mosaic virus, powdery mildew, and rust are the most common rose diseases here. Selection of resistant varieties and proper cultivation practices should prevent many problems. Careful attention to the plants will show when action is needed. Nurseries and CSU Extension can help with advice if needed.
In late fall mound a thick layer of organic matter over the crown of the rose plants. Wood chips, pine needles, or chopped leaves all work well and will protect the plant from the effects of extreme temperature change.
Winter watering for rose plants is very important. Deeply water once each month if the soil is not frozen. Pick a warm day and apply water slowly to the entire root area early in the day so it can soak into the soil before the night freeze.
Climbing Roses Recommended for Colorado
(click on highlighted name for photo and information)
With a small bit of care, a climbing rose will reward you with good health and lovely blooms, enhancing your garden with romance and charm.
Photo of Golden Showers (top of page): Judy Sedbrook
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010