Welcome to the home of the International Cultivar Registration Authority (also called an ICRA) for the genus Hoya, and an online learning resource dedicated to the genus in cultivation.
What is an ICRA? An ICRA is appointed by a commission within the International Society for Horticultural Science (ISHS) with the directive to define, track, and list the names of all cultivated plants within a defined scope in order to promote stability and accuracy in their nomenclature.
How does this work? through the registration and establishment of new cultivar names, Group names, and the listing of each cultivar and Group name already in use. These two parts come together to make a checklist of cultivar names and descriptions so that we can refer to our plants in cultivation. Over time, they may ideally also create an historic record, a list of synonyms, trademarks and trade designations, grower’s codes and more.
What is registration? The Registrar checks the new name and makes sure that it follows the rules of the code. Then we make sure that the name is officially documented with a description and high quality color photographs or an herbarium. We will establish the new name if it has not been published previously. We store all of these records and duplicates in permanent archives with the ICRA and other horticultural libraries so that they will always be available when others want to learn about the cultivar in the future. A full checklist of cultivars is to be published, usually every year, and circulated as both a pdf and book in order to make a permanent record of cultivated Hoya which builds over time.
Register Hoya cultivar and Group Names: If you have a new cultivar to register, or have released one to the market and would like to make your name official, this is the place to begin. Follow this blue link heading and you can fill out the form either by copy and pasting the text into an email or directly. It is free of cost, and does not take long.
If you have been granted variety rights or a certificate (such as patent or PVR for example), or you have published a cultivar name independently and it is not yet on the ICRA checklist, please help us to make sure we know about it and have the correct information in order to add your name and a description or a reference to the publication into the checklist by submitting an application. Note: the ICRA itself does not grant any legal rights.
The Cultivar:
What is a cultivar? 1). The cultivar may originally be selected for one or more features from a plant found anywhere. For just a couple examples common to the genus Hoya and as seen in Article 2 of The International Code of Nomenclature for Cultivated Plants: the features may first be selected from a wild seedling in nature, one among several F1 hybrid seedlings in cultivation, a branch mutation from a long process of sport selection, or somaclonal variation from a batch of otherwise uniform tissue culture. There are plenty of other ways that variation comes about and from which interesting and desirable features may be selected.
2). Once selected, the prospective cultivar is then propagated.
3.).If the original selected features remain distinct, uniform, and stable as multiple generations are propagated, a new cultivar may be named.
What does it actually mean to name a cultivar? Like any other rank and category, it means that an acceptable name has to be published in such a way that the new taxon is well defined. An ICRA is appointed to do this for cultivars, so don’t worry if you aren’t sure how or where. We want to help you publish your name for your cultivar, and be sure that everyone knows about it into the future. We can’t wait to work with you and build a great registry that preserves the names of the plants we love.
Guide to using the Checklist:
Due to its effectiveness, this checklist uses terminology originally from the International code of nomenclature for cultivated plants, but which has been adapted for use in a cultivar checklist by the exceptional Avery Rowe, ICRA & Registrar for the Commelinaceae family of tradescantiahub.uk. Differences and errors both here and in implementation are our own.
Each name may also have any number of categories which relate to its taxonomic classification, color, habit, provenance, and so on. Over time these informal categories will hopefully resolve into clear patterns which may be named as horticulturally valuable formal Groups based on Hoya with shared characteristics.
Accepted The name is accepted as the correct name representing a unique cultivar. It may still need to be formally established in the next print registry. In more simple words, it is the name to use.
Synonym An established name that is not the accepted or adopted name. (ICNCP 11.2-11.3)
Invalid A name contrary to the rules of the code, or which was never published, and/or does not represent a unique cultivar. The epithet should still not be duplicated.
Established Has been published meeting all conditions of Article 27.
Established Uncertain A name which has been established meeting all conditions of Article 27, but which may or may not be attached to a still extant cultivar, or to one which is unique.
In Use the epithet is in use, and is being listed in order to prevent duplication of epithets already in use, but does not confer status.
Cultivar Availability
Mass-produced Cultivars which are produced by wholesalers and are available wherever Hoya are found, or nearly. Produced in great quantities.
Lost This refers to a cultivar which is thought to be extinct and not been documented before the year 2000. (Rowe, tradescantiahub.uk)
Rare Last documented before the year 2020. (Rowe, tradescantiahub.uk)
There is always only one accepted name for any cultivar, even though in some cases multiple may have been established. Many cultigens* (cultivated plants which may or may not have cultivar status, or are of unknown origin) are not necessarily established.
Is the list complete? Are all accepted cultivars here right now?
This is an ongoing checklist. While checklists are always incomplete by their very nature, the ICRA was launched in July of 2023 and the checklist itself went live in January of 2024. There are many names which still need to be added at every status. Over time the objective is to maintain a checklist which also contains market names and trade designations as they come up, as well as the accepted and invalid names of cultivars. Would you or someone you know like to work with the ICRA?
If you have any problems ordering the list, finding a particular cultivar, or have notice any potential errors, please reach out.
Please contact me at any time regarding potential errors, to register a cultivar, and with any questions or concerns.
About the ICRA & Registrar:
I am Rachel Colette Conroy, an independent researcher in Michigan, USA. The library and live Hoya of the ICRA are available to the public by appointment and belong to us all as in perpetuity.
While the ICRA is formally an individual structure, it is made whole by the very tangible support and from the committee members and partners.
Mark Randal: EIC, founder of Stemma Journal.
It is through collaboration with Stemma Journal that new cultivars which have just been registered, or are about to be registered, will be primarily distributed in both print and pdf. We hope that more new originators will want to share and describe their cultivars through this process so that Hoya cultivar names will be clearly established and easily searchable in a way that they have not been in the past. Many of these same people collaborating with the ICRA are a part of a special network with Stemma Journal. If you aren’t a part of the Facebook Group over at Facebook.com/groups/stemmajournal , we hope this might encourage you to check it out for some very cool conversations, and early access to the journal volumes that are hosted on stemmajournal.org .
Michael Green: is a researcher and archivist for the ICRA, alongside his own projects. Through his efforts it has been possible to have eyes on images of cultivars that we previously thought lost, and to add beautiful documents to the library both online and in person. It has also given us further perspective about both old names and new.
Pattamate Watthanasakulcharoen: expertise in Thai cultivars and originators
There are many further contributors who have submitted materials, corrections, ideas, and more in order to help make this better. We are in your debt and you have not been forgotten.
If you have expertise in the International Code of Nomenclature for Cultivated Plants, or special knowledge of cultivated Hoya from a particular region, the ICRA could use your help to make sure the names of all cultivars are accounted for.
Wherever you are in the wider world, welcome to the registry and an online world of Hoya cultivars. If you are here to register a cultivar and learn how to establish its name so that it is official, you are in the right place. This is also the single place to check the correct name for a cultivar within the genus, and its status.