Own-root roses can flourish in Colorado

By Jennifer Miller, Special to the Rocky

Published May 22, 2008 at 5:50 p.m.
Updated May 22, 2008 at 6:53 p.m.

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Photo by Photos By Ellen Jaskol / The Rocky

William Baffin roses climb a trellis and archway near a Denver home.

Pink Meidiland shrub rose

Prairie Sunrise rose

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Poet Robert Burns probably would not have compared his love to "a red, red rose/That's newly sprung in June," if he saw a Dr. Huey rose overtake his beloved grafted hybrid tea.

When a rose is grafted, it's budded onto the rootstock of a sturdier rose, often the rambler Dr. Huey. If that graft with the rootstock dies, then the rootstock springs up in its place. To the gardener, it often appears as if their rose has changed color, when in fact they are looking at blossoms from the rootstock, not the grafted rose.

So many hybrid tea, floribunda and grandiflora roses are grafted today that gardeners regularly joke online that they were "Hueyed" or they shoveled out "Dr. Phooey."

Gardeners can avoid graft problems altogether by planting hardy roses that grow on their own roots.

Grafted roses don't age as well as roses grown on their own roots; over time grafts tend to callus over, leaving less room for new shoots.

When Dr. Huey or another rootstock wins out, there's not much left to do but yank out the rose and try again. But tossing a rose every time the graft fails can be costly.

"By the time you spend $20 on a rose, you don't want to treat it like an annual," noted Mikl Brawner of Harlequin's Gardens in Boulder, which specializes in growing own- root hardier roses.

Own-root roses are grown from cuttings, and therefore are the same rose from root to flower: exactly what you thought you bought.

"I've seen a lot of interest in roses in general because there's a lot more breeding and availability of roses that are more cold-hardy, and part of that is the own-root factor," Brawner said. Harlequin's offers more than 200 varieties of cold-hardy roses.

According to Brawner, if hardy own-root roses die back to the ground, they usually come back from the roots. Additionally these tougher roses are less likely to be infected by viruses, and tend to live longer, sometimes for generations. (Brawner said gardeners are lucky if grafted roses last 5 to 10 years.) Hardy own-root roses also are more free-flowering, since they put up more canes.

But if you want an own-root rose, you'll need to be patient. Part of the appeal of grafted roses is they reach maturity faster than own- root. Budded to year-old rootstock then grown another year before shipped to retailers, they take off the summer you buy them. Own-root, on the other hand, take 2-4 years to mature.

Almost any rose can be grown on its own roots, but only the hardiest varieties will flourish in Colorado.

Among the most reliable are the own-root modern shrub and carpet roses.

The Canadian breeding program's Morden shrub roses offer hybrid tealike blooms all season, while the Buck roses, bred by Iowa State University's Griffith Buck, have large, fragrant, semidouble flowers all summer. Another popular series, though a bit less cold-hardy, is Meidiland, a vigorous group of spreading roses from France. Two others that are widely sold are the repeat-flowering Flower Carpet and Knockout series.

Some of the most intriguing are the own-root David Austin hybrids - those lush, soft-blossomed rose shrubs developed by England rose breeder David Austin. The own-root Austins, a cross between old roses and hybrid teas, aren't as cold-hardy as the Canadian, but the hardiest of them reliably come back from their roots. (Most Austins are still grafted, so ask specifically for those grown on their own roots.)

Others to consider are heirloom roses. They tend to bloom only once, but all the energy goes into that one bloom, so it's spectacular, as is often the fragrance.

Whatever you love, know what you're buying. If shopping at a garden center, a general rule of thumb is that many roses are grafted unless labeled "own root" on the plant tag.

Five with flourish

The following are five of the many roses that thrive on their own roots in Colorado:

* Rosa Mundi (Gallica). Semidouble crimson blooms with white and pink stripes and splatters and mild scent. The shrub grows up to 4 feet tall and blooms heavily from midspring to early summer.

* Abraham Darby (Austin). Cabbagelike apricot-pink double flowers with rich, fruity fragrance. The shrub grows up to 10 feet tall and begins blooming in late spring then repeats through summer.

* Zephirine Drouhin (Bourbon Climber). Deep pink flowers with raspberry fragrance on thornless stems. The climber grows up to 12 feet, is shade tolerant and puts on its best show in spring, but regularly blooms into fall.

* Madame Hardy (Damask). Pure white flowers with green button eye, and a musky, honey-like scent. The upright bush grows up to 6 feet tall and can tolerate poor soil. It blooms once, for up to six weeks per summer.

* Morden Sunrise (Canadian). Semi- double flowers that open from orange buds to become soft yellow, apricot pink, then orange, with a tea- rose fragrance. The shrub grows up to 3 feet tall and blooms almost continuously from late spring.

Planting tips

* Plant roses in a large hole dug 18-24 inches across and 14-18 inches deep. Mix in 1 part compost to two parts soil, a cup of Mile High Rose Feed and a cup of ground or pelleted alfalfa.

* Plant the rose 4 inches deeper than it was in the pot, then mulch with 4 inches of wood chips or shredded leaves.

* Apply water slowly and deeply, deadhead spent flowers and mulch in winter to a depth of 4-8 inches.

* For more detailed instructions, go to harlequinsgardens.com. Also, the Denver Rose Society and Colorado State University Extension Office list favorites and offer growing tips.

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