History of Knockout Roses

Red Double Knockout Rose

The most popular rose in America, known as ‘KnockOut,’ was created by William Radler in his basement, just outside Milwaukee, Wisconsin.  For fifteen years, Radler labored alone, patiently nurturing thousands of seedlings under grow lights until the desired result was achieved. Released to the general public seventeen years ago, 90 million ‘KnockOut’ roses have since been planted across the country.

The combined presence of five characteristics has made ‘KnockOut’ roses such a success: disease resistance (no black spot or powdery mildew), drought tolerance, cold tolerance, self cleaning (no dead heading required), and continuous bloom.  Some people complain  that KnockOuts have no fragrance and do not last as long in a vase as most rose varieties do. The bushes also grow up to six feet tall or taller and are among the thorniest roses you will find.  Still, as a minimum maintenance hedge for near constant color — ‘KnockOut’ varieties include pink, red, yellow petals fading to white, and coral petals with yellow centers — nothing can compare to ‘KnockOut’ roses. For the record, the first ‘KnockOut’ rose is said to have been created by crossing seedlings of ‘Carefree Beauty’ and ‘Razzle Dazzle’ varieties.
As for the criticism that ‘KnockOuts’ lack fragrance, it is argued that their scent is more delicate and fruitier than the classic rose fragrance and, furthermore, that they are actually shrub or landscaping roses which, in any case, are not grown for their smell.
It is interesting to note that the first ‘KnockOut’ roses were singles, meaning the roses had a single tier of only five petals per flower.  These singles are a reminder of what roses looked like before hybridization.  Although people speak of classic roses as if they always had multiple tiers or layers of petals, the truth is that nearly all wild or species roses have a single tier of five petals only.  Rather, it is in hybrids that a proliferation of petals, which may exceed more than a hundred per rose in some varieties, predominate.  It should be mentioned that ‘Double KnockOut’ roses are later versions of Randler’s originals and, as their name implies, they have a double layer of petals.  And ‘Sunny Knockout,’ by the way, is highly fragrant too.
The genius of Radler was to start with disease resistance as his top priority.  Until Randler’s ‘Knockouts’ came along, rose breeders had nearly always focused on shape, size, color, and fragrance, with disease resistance not a primary concern.  There were some exceptions, such as white and pink ‘Iceberg’ and ground cover ‘Floral Carpet’ roses, which come in a wide variety of colors.  These roses, also notable for their disease resistance, preceded the release of ‘Knockouts’.
It makes sense that single tier roses, in their resemblance to wild types, are more disease resistant than hybrid roses, just as mutts are generally healthier than fancy pedigree dogs.  Radler is so obsessive in his demand that only disease resistant varieties leave his basement rose laboratory that he injects fungus into his plants, irrigates them with overhead sprinklers, and even covers them with wet leaves.  Only varieties that survive such exposure and conditions without any signs of fungus infection are planted out in the garden for further evaluation.
Just because a seedling rose shows magnificent qualities in Randle’s basement does not necessarily mean it will become a commercially desirable variety.  Only after the plant in question has matured in three to five years will it be considered garden worthy or not.  The shape of the mature plant will have been evaluated by then, as well as its flower production, cold tolerance, and other qualities.
Rose breeders benefit from the fact that roses are rather precocious bloomers.  If you plant an apple seed, the tree that grows may not give you flowers (and fruit) for 10 years.  An orange seed will turn into a tree that bears its first flowers in no less than 7 years.  A fat avocado seed becomes a flower (and fruit bearing) tree at around 5 years, and a peach tree that grows out of a pit may finally flower at the age of 3.  In fact, woody plants of any description, grown from seed, will generally take several years, at a minimum, to produced flowers and fruit.
Hybrid roses, however, may flower as soon as five or six weeks after their first baby roots and leaves have sprouted.  So you will know, soon enough, if the new flowers you see are attached to a plant worth keeping.
Although roses may flower when very young, there is an elaborate process that goes into preparing the seeds for planting.  There are two goals in mind:  preventing the seeds from drying out on the one hand and preventing fungus infection on the other.  You can harvest rose fruit (known as hips) this time of the year.  The hips may be slightly shriveled but don’t let them dry out too much before harvest or the seeds within will not sprout.  Cut open the hips and remove all traces of pulp that cling to the seeds since this pulp will also inhibit germination.  As recommended by Kitty Belendez of the Santa Clarity Valley Rose Society, you should rinse the seeds in a solution of bottled water and 5% bleach (2 teaspoons of bleach per cup of water). Then place the seeds in a strainer and rinse them with bottled water and, afterwards, soak the seeds for 24 hours in a 3% peroxide solution.  For complete, yet gentle pulp removal, agitate the seeds in a Cuisinart with a plastic dough blending attachment.  Make sure seeds are covered with several inches of bottled water before running the Cuisinart.
Now place the seeds on a paper towel, moistened with a 50% bottled water and 50% peroxide solution, and then fold it over to cover the seeds.  Place seeds with paper towel in a zippered plastic bag and refrigerate for 60 days.  Alternatively, you can plant the seeds in the shallow cells of germination trays and place the trays, covered in plastic, in the refrigerator. The key here is making sure the seeds do not dry out while in the refrigerator.
Prior to planting the seeds in trays or small pots, before or after refrigeration, treat them with a root hormone, available at most nurseries, that contains a fungicide.  Soil mix should be 50% vermiculite and 50% fast draining, sterile potting soil.  Even after all of this preparation, do not be discouraged if only 20% of your rose seeds sprout, since this is typically the case.
The most delightfully informative website on roses that I have found is located at scvrs.homestead.com. SCVRS stands for Santa Clarita Valley Rose Society and no other website on roses can match it for vital detail and readability.  I doubt there is any question regarding the history or care of roses that is not answered here. In addition to its monthly meetings (2nd Sunday of most months at 2:30 p.m., 22900 Market Street in Newhall), SCVRS publishes a highly informative newsletter and organizes garden tours and rose shows as well.
Tip of the Week:  A company called Glogro has designed an apparatus for growing plants indoors where an LED grow light doubles as an attractive floor lamp.  The only limit to what you can grow is size, since there is a three foot space between the lamp and hanging basket, situated directly under the lamp, in which your plant(s) will grow.  While herbs and annual flowers are highly recommended for such a growing environment, a miniature rose bush would be a perfect candidate for such a space since most miniature roses grow less than three feet tall and many do not even reach two feet in height. For more information on this product, go to www.glogrolighting.com.

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