Plant Patents on Knock Out Roses

Question: I would like to propagate some of my Knock Out patented roses to share with friends. Is this legal, and if so, what’s the best way to do it?

Most species of roses require significant time and effort to keep them healthy and free of disease and insect pests. Then … along came the Knock Out rose. Developed by William Radler after years of breeding, it was introduced to the market in 2000. It has become the most widely sold rose in North America. Knock Out roses were awarded the All-America Rose Selection designation in 2000 and 2007.

Image Source: University of Florida, Institute of Food & Agricultural Sciences

Knock Out Roses, A Gardener’s Favorite
A triumph in breeding, these easy to grow shrub type roses have dark green foliage, profuse blooms from spring until frost and grow to 4 feet in height at maturity. They have a mild fragrance, come in a variety of colors (red, yellow, pink, multicolor) and can be planted individually or in groups, as borders or in beds with annuals or perennials. They are heat and humidity tolerant and winter hardy in USDA plant hardiness zones 5 (with some winter protection) to 9. They require minimual maintenance (no pruning or dead-heading). They are resistant to most fungal diseases, including black spot or powdery mildew, but like other varieties of roses, insect pests may need to be controlled. They are a landscape rose and do not last long as cut flowers.

Image Source: University of Tennessee Extension, Institute of Agriculture

Plant Patents
Due to the time and money invested in breeding the Knock Out rose, it was patented in 2000. As stated in a University of Tennesse Extension, guide:

“Plant patents are granted to those who discover or invent a n and distinct cultivar and asexually reproduce it. Plant patents allow the patent holder to prevent others from asexually reproducing the new plant without first entering into a licensing agreement.”

In other words, if a Knock Out rose is patented, it should not be propagated from cuttings, tissue culture, buds, layering or grafting of plant stems, roots or leaves without written authorization or a license agreement with the patent holder. Anyone propagating a patented plant without authorization has violated patent law, even if the infringement is unintentional or it is just being planted in your own back yard. Patent violations can result in payment of actual damages or a royalty payment for unauthorized use.

Identifying Patented Plants
A number of new varieties of Knock Out roses have been introduced since 2000 and have been patented. To check for a patent on a newly purchased plant, look at the plant tag for the abbreviation for the patent (PP+patent number), plant patent applied for (PPAF) or plant variety rights (PVR) after the name of the plant.

Plant patents are in effect for 20 years from the filing date of the patent. However, even if the plant patent has expired, there may be other legal protections in place (trademark, utility patent, plant variety rights certificates). In other words, before propagating a plant, be sure to check that it is not subject to these requirements. The University of Tennessee Extension has published a comprehensive description of the various requirements under patent law along with examples of patent violations.

Despite patents on some plants, many plants can be propagated. Learn about propagating other types of roses from cuttings. Have another plant that you wish to propagate? Virginia Cooperative Extension has good information on propagation by cuttings, layering and division.

A Green Industry Guide to Plant Patents and Other Intellectual Property Rights”, The University of Tennessee Extension, 27 Feb. 2021.

A Rose is a Rose…Not Always! Look at ‘KnockOut’ Landscape Roses”, University of Maryland Extension, Updated 22 Apr 2021.

General Information About 35 U.S.C. 161 Plant Patents”, United States Patent and Trademark Office.

Knock Out Roses”, University of Florida, Institute of Food & Agricultural Sciences, Gardening Solutions.

Propagation by Cuttings, Layering and Seed”, Relf, Diane, Exension Specialist, and Ball, Elizabeth, Program Support Technician, Virginia Tech, Virginia Cooperative Extension, Publication 426-006, 1 Oct 2019.

The Knock Out Family of Roses”, Star Roses and Plants, 2021.


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