New Official Cultivar Names

It has recently come to my attention that there is still some confusion about plant registration as well as the benefits of registering new plant cultivar names. This article will aim to clear up this confusion by explaining the registration process and clarifying the role of plant registrars.

The IWGS serves as the International Cultivar Registration Authority (ICRA) for both Nymphaea and Nelumbo. I serve as the registrar for waterlilies (Nymphaea) while Professor Daike Tian serves as the registrar for lotus (Nelumbo). As the registrars for these two genera, we are responsible for ensuring that each new cultivar name adheres to the guidelines put forth in the International Code of Nomenclature for Cultivated Plants (ICNCP). This publication is created by the International Society for Horticultural Science and details the rules and recommendations for naming plants in cultivation. A downloadable copy of the ICNCP is available at…

The main objectives for having a single international set of guidelines for the naming of new plant cultivars are to promote stability and continuity in the process while also ensuring that new cultivars are not given names which already exist, or names that too closely resemble existing names, even if those names were never formally registered. It is recommended that each registrar also maintains a “checklist” of cultivar names—that is, a list of those names that are unregistered but that have been published or made known in the literature—a task that is currently underway. The IWGS is also close to unveiling a searchable online database of existing cultivars.

When a hybridizer has a new waterlily or lotus cultivar they would like to name and register, they can download the appropriate registration form from the IWGS website and fill out the required information. This information will include details such as the year of hybridization, parent plants if known, RHS Color Chart data for all plant parts including petals, sepals, leaves, etc., along with measurements of blooms, leaves, and the entire plant. Photos of the new cultivar are also required. Once the requirements for registration are completed, a registration certificate is issued by the registrar to the hybridizer. All plant registrations are then published annually in the 4th Quarter of the IWGS Water Garden Journal—a process which formally establishes the new cultivar name.

While we have covered what plant registrars are responsible for, it is important to also note what does not fall under their areas of responsibility. Registrars are not responsible for determining the uniqueness of a cultivar, nor are they responsible for conducting plant trials to determine the stability of a plant cultivar or other growth characteristics. These questions may be asked on the registration forms, and it is expected that a hybridizer will provide accurate information about a cultivar’s uniqueness, stability, and growth characteristics. The registration of new plant cultivar names is a voluntary process and it should also be noted that registering a plant name does not give the hybridizer any legal protections over the new cultivar. Legal protections can be obtained through other methods such as plant patents.

The system of registration is one that benefits everyone, from people in the nursery trade, to authors, researchers, teachers, governmental bodies, taxonomists, and hybridizers themselves. By working together to ensure that new cultivar names are formally registered, we can create a reliable and straightforward system to name and catalog these plants that we all love.

I hope that this article has helped to answer some of the questions surrounding plant registration. If you have further questions, feel free to contact me.

About the Author Tamara Kilbane is the Senior Horticulturist, Aquatics, at the Denver Botanic Gardens.

She can be reached at