OSU Extension has completed a review and update of guidance related to plant propagation and plant sales, with a focus on reducing the spread of invasive pests and protecting Oregon’s gardens and natural areas.
This guidance reflects collaboration among OSU Extension faculty, the Oregon Department of Agriculture (ODA) and Master Gardener volunteers. It is soon to be published as an official OSU Extension educational resource. The forthcoming publication can be viewed on the second page in this post.
While this guidance was developed in response to questions related to Master Gardener plant sales, it applies to all plant propagation and plant sales conducted under the Master Gardener name.
Required actions for Master Gardener volunteer plant sales
- Apply for a temporary nursery license (required)
All Master Gardener–sponsored plant sales in Oregon must have a temporary nursery license from the Oregon Department of Agriculture.- Apply for a nursery license (scroll down to “Temporary Nursery License” for the application form).
- The license helps ODA track plant movement in quarantine areas and prevent the spread of invasive pests.
- Use only clean plant material
- Do not propagate or sell plants dug from home gardens or landscapes (including “dig and divide” plants).
- Propagate only from:
- Commercially grown starts, plants, bulbs, or tubers
- Seed
- Cuttings taken from healthy plants that are grown in sterile media
- Washing or dipping roots, tubers, or bulbs is not an acceptable way to remove soil or pests or to treat diseases.
- Use clean containers, tools and growing spaces
- Use new or sanitized pots, trays and containers.
- Use commercial or sterilized potting media.
- Clean and sanitize tools, benches and work areas.
- Follow the product’s label directions and safety guidance when using sanitizers.
- Inspect plants before sale
- Carefully inspect all plants prior to sale.
- Remove and discard any plants showing signs of disease, insect damage or infestation.
- For help with diagnosis, use:
- Properly identify and label all plants
- Confirm plant identity before sale.
- Cross-check plants against Oregon noxious weed lists such as Oregon Noxious Weed Profiles.
- Label each plant with:
- Scientific name
- Common name
- Cultivar, if known
- Remove volunteer seedlings from containers before sale.
Why this matters
Moving plants and soil is one of the most common ways invasive pests spread. These best practices help protect Oregon’s gardens, farms and natural areas, and ensure that Master Gardener plant sales reflect the high standards and science-based practices the public expects from OSU Extension.
Please review the full OSU Extension guidance carefully (forthcoming publication on second page of this post) and use it to guide planning for future plant sales and propagation activities. If you have questions about how this applies locally, contact your county coordinator.
Thank you for your continued stewardship and leadership in your communities.
Thank you. We are following these guidelines and appreciate the accuracy of these.
This is a very informative and interesting post. Thank you for sharing clear updated guidance and required steps for Master Gardener volunteer plant sales. Your posts are always helpful insightful.
Question: if a garden club has a one or two day booth at a fair or event, with items for sale including plants and starts from home gardens, are these sales subject to these restrictions? Not talking about a Master Gardener sponsored event -just a local club selling plants or starts.
Hi Katharine. See the link to applying for a temporary nursery license and check with the ODA to find if your particular set up has this requirement. Also, keep in mind the risk you run when sharing plants from your gardens, and inadvertently sharing invasive pests: that’s a sale no gardener would like to make.
All good advice, with one exception. Under the the heading:
“Use clean containers, tools and growing spaces”
you recommend “Use new or sanitized pots, trays and containers.”
I would remove the word “trays”. It makes no sense to have to sanitize trays that hold the sanitized pots. Are you worried the unsanitized trays will magically contaminate the soil through the bottoms of the sanitized pots? This requires a lot of unnecessary extra work for our plant sale…
Helpful article! I have a question about this statement:
“Do not sell or share plants dug from home gardens or landscapes (including “dig and divide” plants).”
I understand the theory, but I’m wondering if there is any scientific evidence that selling dig-and-divide garden plants at a nonprofit plant sale actually spreads pathogens or pests at a greater rate than occurs naturally?
Hi Doug. Here’s some responses from several authors of this article:
If you look at the footnotes of the policy, there are a few studies that were cited. There are easy to find studies/articles on the spread of invasive plants through plant trade (example: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/fee.2392), and the USDA-APHIS offers guidance on moving plants (https://www.aphis.usda.gov/plant-pests-diseases/hungry-pests/how-stop-them/think-you-move-plants-or-soil). However, I don’t know if there are studies on the spread of pests through non-profit plant sales compared to natural spread.
Our guidelines are about following best practices, reducing risk, and preserving the reputation of our MG program and Plant Sales.
The mechanism by which dig-and-divide plant sales could spread pests and pathogens faster and farther than natural spread is well-supported in the peer-reviewed literature. The magnitude of that effect specifically at nonprofit community sales has not been studied/I couldn’t find it. The guidance is grounded in organism biology, best practices and general principles not in epidemiological studies specifically designed around plant sales.
So if someone is looking for direct, controlled comparisons between nonprofit sales and natural spread, those are hard to find (if any). But the biology is well understood, and broader research consistently shows that moving plants around by people spreads pests and pathogens much more quickly than natural processes.
Some examples:
Research on Phytophthora plurivora concluded that diseased nursery stock , not natural spread was the mechanism that moved the pathogen from Europe to North America https://pmc.ncbi.nlm.nih.gov/articles/PMC3888410/
Population genetic studies of Phytophthora ramorum, for example, traced its spread across the United States almost entirely through nursery trade networks rather than through natural aerosol or wind dispersal https://pmc.ncbi.nlm.nih.gov/articles/PMC2736564/
A published nursery study demonstrated that Phytophthora-infected container plants introduced the pathogen into surrounding plant communities when planted, confirming that soil and roots in plant containers are functional transmission vectors https://apsjournals.apsnet.org/doi/10.1094/PDIS-05-17-0689-RE
Thanks for the thorough reply – appreciate it!