Friday, November 07, 2008
A primer on Knock Out roses: Start planning now for early spring
John Arbogast
Landscape consultant John Arbogast answers your questions every Thursday. Send questions about your lawn, garden, plants, or insects to:
Dear John
5102 Greenfield St. SW
Roanoke, Va. 24018
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Q: My wife and I love roses, but I'm tired of spraying for blackspot disease, watching rose leaves turn yellow and fall off, pruning off dead rose blooms as soon as possible, and all the other rose maintenance chores needed in order to get beautiful roses all summer. What can we do here in western Virginia to have roses without all the bother?
A: Early next spring, switch all your roses that are in full-sun locations with decent soil to varieties of the medium-height shrub rose called Knock Out Rose, which should be available from local garden centers and definitely from mail-order catalogs that specialize in roses.
We learned from the school of hard knocks about Knock Out roses and sunlight when we planted three pink Knock Out roses two springs ago here in Roanoke. They were in a place that got full sun for part of the day and then were shaded for the remainder of the day. Turns out, they really need full sun for prolific season-long flowering. This past spring, we transplanted our Knock Outs into an all-day sunny spot and we've been impressed with their abundance of continuous blooming, even into the fall.
The time-saving qualities that Knock Outs offer include outstanding disease resistance, good drought tolerance after their first year (with weekly watering), and their self-cleaning attribute, which means that we gardeners don't have to prune off faded roses in order to get new blooms.
The pink Knock Out roses we have are spaced three to four feet apart, grow to 3 feet tall and about 4 feet wide, only need to be fertilized with rose food in the spring just before or very soon after new growth begins, and survive in United States Department of Agriculture Cold Hardiness Zones 4 to 10. Roanoke is in USDA Hardiness Zone 7. Zones with higher numbers have milder winters and those with lower numbers have colder ones. All Knock Out roses are heat-tolerant throughout the entire United States.
Let me give a few more facts to support my enthusiasm for Knock Out roses. The Radrazz variety was the original member of the Knock Out rose family, which was the new shrub rose that set this standard of a rose with superior disease resistance and little to no maintenance. The Radrazz makes rich, cherry-red blooms continuously until the first hard frost. It won a 2000 All-America Rose Selections honor. Radrazz is still available from Star Roses and The Conrad-Pyle Company. It is a compact, mounded and bushy grower with deep, mossy green leaves, one to five flowers per cluster with up to 25 blooms per flowering branch, light tea rose flower fragrance, a size of 3 to 4 feet tall and three to four feet wide, and suitability in USDA Zones 5 to 9.
Let me continue convincing you that you should try Knock Out roses by giving a little more information about what colors and flower types are available. The Double Knock Out Rose Hybrid variety Radtko produces a profusion of deep cerise, cherry red, 3- to 3.5-inch diameter double-form blooms with a light tea rose fragrance. It has an average size of 3 to 4 feet in both height and width.
The Pink Knock Out Rose, commonly called Bright Pink Super Bloomer variety Radcon, has delicate-looking single petals in a gorgeous shade of bright pink. It grows about 3 feet tall with a 4-foot bushy width. Its blooms have no fragrance, but they are prolific. It joins the list of other Knock Out Roses as being the most disease-resistant on the market -- and the most drought-tolerant.
The Pink Double Knock Out Rose, commonly called Bubble Gum Pink Full Double Flowers variety Radtkopink, produces a profusion of pink, double-form lightly fragrant flowers on plants that are 3 to 4 feet wide and tall.
The Rainbow Knock Out Rose, also known as A Plantable Rainbow variety Radcor, produces uniquely colored coral pink blooms with yellow centers. The Rainbow Knock Out Rose is more compact than the other Knock Outs. It was a 2007 AARS winner.
The Blushing Knock Out Rose, called A Delicate Pink for any Garden, variety Radyod, is another bushy Knock Out rose with great disease resistance and drought tolerance. The name "delicate pink" describes the pleasing bloom color.
And, before you think that all Knock Out Roses have red, pink or rainbow flowers, there is Sunny Knock Out Rose, also called Sunny and Super Fragrant variety Radsunny, which produces a profusion of yellow or pale yellow blooms and fragrant stems.
