- User Edits
- International Cultivar Registration Authorities (ICRAs)
- Plant Patent Information
- Plant Societies
- Botanical Gardens and Arboretums
- Plant Databases from Universities
- Reputable Nursery Websites
- Native Plant Societies
- Print Resources
- Miscellaneous Approved Resources
- Water Use Classification of Landscape Species (WUCOLS) – California-Specific
Want to know which resources we use in vetting the plant data added by Land F/X users in our plant data tagging system? Here are a few examples of the types of resources we reference.
Because Land F/X users are knowledgeable landscape architects, user edits play a major role in our plant data system. Our database manager cross-checks user edits when possible using one or more of the additional resources listed below.
International Cultivar Registration Authorities (ICRAs)
An ICRA is a group – most commonly a botanical society – designated by the International Society for Horticultural Science (ISHS) as the leading expert on a given genus or species of plants. An ICRA will use its expertise to verify taxonomy and data about the genus or species in its care. One example is the American Boxwood Society, which has published a document clarifying the taxonomy and descriptions of common horticultural selections in the genus Buxus.
Another example is the U.S. National Arboretum, the ICRA for the genera Cercis and Lagerstroemia, as well as for woody genera not assigned to another ICRA.
To read more about ICRAS, see the ISHS page on the topic or the directory of ICRAS.
Plant Patent Information
Plant patents are trusted sources of information because they come directly from the breeder of the original plant material, who pays close attention to the characteristics of the given plant.
One example is the hybrid Astilbe "Flamingo" (PP12664). Patents often show the parentage of a cultivar, like this one, which is a hybrid between Astilbe x ardensii and Astilbe japonica. For this reason, we have this cultivar listed in the Astilbe x category, noting that it is a complex hybrid.
Patents can be found easily using a Google patent search.
Even plant societies not deemed ICRAs can be great resources for plant data. Plant societies often include experts on a particular plant group, as well as a number of plant enthusiasts who are continually observing, and reporting back on, their favorite plants. Examples include:
- American Camellia Society
- American Conifer Society
- American Daylily Society
- American Peony Society
- American Rhododendron Society
- Bromeliad Society International
- California Rare Fruit Growers
- Pacific Horticulture Society
Botanical Gardens and Arboretums
Botanical gardens and arboretums often report data that originates from direct observation of the plants in a landscape, and is therefore usually extremely trustworthy. Examples include:
- Great Plant Picks (Elisabeth C. Miller Botanical Garden)
- Missouri Botanical Garden
- Mt. Cuba Center
- Morton Arboretum
- U.S. National Arboretum
- Plant Select (Denver Botanical Garden and Colorado State University)
Plant Databases from Universities
Multiple universities have built reputable databases for horticultural plant materials. Examples include:
- Select Tree – Urban Forest Ecosystems Institute (UFEI), California Polytechnic University, San Luis Obispo (Cal Poly)
- Extension Gardener Plant Toolbox – North Carolina State University
- Oregon State University (OSU) Landscape Plants Database
- University of Florida Plants Database
Reputable Nursery Websites
Run by the people who grow and sell the plants, nurseries have a stake in getting the data right about the plant material they're selling. They're also often familiar with the plants as a result of working directly with them. Examples include:
- Far Reaches Farm
- Hoffman Nursery
- Frank Schmidt & Son Co.
- Las Pilitas Nursery
- Plant Delights Nursery
- Prairie Moon Nursery
- San Marcos Growers
- Select Trees
- Van Den Berk (Netherlands)
- Xera Plants, Inc.
Native Plant Societies
Native plant societies are especially great resources for plants that are less common in the horticultural trade. Examples include:
- California Native Plant Society's Calscape
- New Zealand Plant Conservation Network
- Ladybird Johnson Wildflower Center
Books, such as the Sunset Western Garden Book and Dirr's Encyclopedia of Trees and Shrubs, have been vetted thoroughly for accuracy and are therefore good resources. Beware of older taxonomy in older print resources, however.
Occasionally, great blogs that document working with plant materials firsthand, such as Paghat's Garden, can be used as reputable resources.
Water Use Classification of Landscape Species (WUCOLS) – California-Specific
WUCOLS is a resource for plant water requirements specific to California, created via collaboration among multiple California water use authorities. Our plant data includes WUCOLS water use data across all location categories, so you may see a range of uses listed. Because our plant database is used worldwide, you may also see water use ranges that occasionally vary more than those covered in WUCOLS. If these tags are locked, it means they have been triple checked for accuracy.