fern propagation

Taxonomy

When propagating plants, it is important to know what species you are working with. The only accurate way to do this is by using the scientific binomial name.  Theoretically, there should only be one binomial name for each plant but there are several authorities, and molecular data is changing our understanding of the relationships between living organisms. Walmer Woodlands has a relationship with several organizations, and they do not always agree on how ferns and other plants should be classified. Therefore, it becomes important to communicate so that we agree on what plant we are referring to even when there is not a consensus due to the evolving situation.
The NC State Plant Toolbox under the guidance of Scott Zona, uses the classification system developed by the Royal Botanical Garden, Kew called Plants of the World Online (POWO). POWO provides references to how and when plants were named along with a list of recognized synonyms to help understand some of the name variations.

The NC Botanical Garden created an app called FloraQuest, which focuses on native plants in the Southeastern United States. 

Tony Avent, the founder of the Juniper Level Botanical Garden / Plants Delight Nursery in Raleigh, NC, has been generous in sharing his knowledge.  He recently directed me to a research article entitled, “A community-derived classification for extant lycophytes and ferns” published in the Journal of Systematics and Evolution (November 2016). This article describes a group called the Pteridophyte Phylogeny Group, which aims to create a consensus opinion regarding lycophytes and ferns specifically. 

Finally, Brian Aiken, who is the curator for the American Fern Society spore exchange program, has been incredibly generous in sharing his techniques for spore harvesting / culturing and fern identification.  Brian also uses the classification system developed by POWO.

Fern Lifecycle

How to collect spores

- American Fern Society (AFS)

- British Pteridological Society BPS

American Fern Society fern propagation / spore viability test

Spores are sown on sterilized Pro-Mix HP soil or hydroponic agar and maintained for 8-16 weeks at room temperature 11 inches below two 20W cool white, fluorescent tubes (or equivalent) illuminated 14 hours per day.

I have been using clear, plastic or glass food storage containers containing PRO-MIX HP MYCORRHIZAE™ as my substrate and potting soil for young plants. This medium is a high porosity peat-based growing medium containing, beneficial mycorrhizal inoculum (Glomus intraradices). This formula ensures optimum growth, especially when high air capacity and extra drainage are required. It is ideal for water sensitive crops, rooting cutting and/or low-light growing conditions.

When to collect spores

Advice from the British Pteridological Society

Brooklyn Botanical Garden propagating ferns from spores 

Ferns propagated from spores at Walmer Woodlands

1. Ctenitis subglandulosa 'so fine', fronds harvested 9/5/23 with Dr. Pat MacMillan at JLBG, stored at 40 degrees F, spores isolated and cultured on Sphagnum peat moss 10/2/23
2. Polystichum acrostichoides, Christmas Fern (NC Native) 
3. Dryopteris erythrosora, Autumn Fern (Introduced)
4. Dryopteris marginalis, Marginal Wood Fern (NC Native), spores collected 7/20 by BA at AFS (1064), stored in refrigerator, dry, cultured on sterilized Pro-Mix HP 1/22/24 , #11
5. Homalosorus pycnocarpos, Glade Fern (NC Native), fronds collected 9/5/23 by dkw at JLBG with Pat McMillan, cultured on sterilized Pro-Mix HP 7/4/23 (culture #3), prothalli appeared in 14 days 7/18/23, first fern fronds appeared 83 days after the prothalli appeared 12/29/23, this species was challenging to harden, ferns planted outside in freshly mulched garden 5/23/24, squirrels dug through mulch and destroyed young ferns, 42 ferns sold to NCBG 9/30/2024
6. Onoclea sensibilis, Sensitive Fern (NC Native)
7. Osmunda claytoniana, Interrupted Fern (NC Native), spores collected 05/2023 by BA at AFS (1390), stored in freezer, dry, cultured at ww on sterilized Pro-Mix HP January 21, 2024, ww culure #7
8. Osmunda regalis, Royal Fern (NC Native)
9. Osmundastrum cinnamomeum, Cinnamon Fern (NC Native), spores collected 5/23 by BA at AFS (1389), stored in freezer, dry, cultured on sterilized Pro-Mix HP 1/21/24, #8
10. Polypodium virginianum, Rock Polypody (NC Native)
11. Polystichum munitum, Western Sword Fern
12. Thelypteris palustris, Marsh Fern (NC Native)
13. Woodwardia areolata, Netted Chain Fern (NC Native)
14. Woodsia obtusa, Blunt-lobed Cliff Fern (NC Native)