April 19 Fern Society

April brings demonstrations and practice with container planting and also the popular Spring Garden Sale. Those attending Thursday April 19, 7:30 pm, Casa del Prado Room 101, will have the opportunity to plant a container with ferns or a combination of plants. A few containers and some ferns will be available for cash purchase. Planting mix will be provided.

Spring Garden Sale this Month

Bring a little cash to enjoy the Garden Sale. This is our opportunity to creatively reuse the gardening items many of us collect. These gardening treasures are too good to throw out, but no longer needed and can be offered to others. This sale provides a great opportunity to buy and sell plants between Fern Society members.

You may donate some ferns and specialty plants to the sale, or sell them on consignment. As always, make sure plants are in clean containers or mounted or bagged, trimmed and free of pests. A correct plant name is desirable. All items must be tagged with seller name and price.

You may either donate or sell on consignment:
• ferns and specialty plants
• decorative containers (no plastic nursery pots)
• terrarium containers
• small water features, garden art
• tools in good condition
• gardening books
• plant stands
(No pesticides or toxic substances)

There will be additional ferns on the Plant Table. Sales are in cash.

Report on March Fern Society

Cindy Benoit of the San Diego County Fair Garden Show shared basic principles of garden design with the Fern Society in March. Cindy is the Garden Show Coordinator and Cheri Kenney is the Assistant Coordinator.

A registered Landscape Architect, Cynthia Benoit has created award-winning residential and commercial landscapes. She has a website, benoitexteriordesign.com. Cindy shared ideas regarding color with green plants and strategies for limited gardening space such as vertical gardens. Her design principles, Focal Point, Balance, Scale, Harmony, Repetition/Rhythm, Unity and Contrast, were illustrated for her talk with photos. These ideas can be used in the home garden, and also for the Fern Society display at the San Diego County Fair. Even a small display needs a focal point, generally with taller plants or structures behind. In the case of ferns, it is helpful to provided repetition, using multiples of small ferns rather than having every single plant be different. Contrasting plant shapes and fern fronds lend interest.

There is still time for individuals to enter container plants in the Garden Show, up until May 4. Using a credit card for the entry fee, register at sdfair.com. Cheri Kenney at 858-792-4207 can answer questions or help with the registration for those without computer access.

Unusual plants, hiding in the garden

Marsilea drummondii1
Here on Bob Charlton's patio, an aquatic fern grows that adapts to dry San Diego with irrigation,
Marsilea drummondii. This fern is native to Australia. Plants may be kept in a small water garden on the patio or even a larger pond. Alternately, grow Marsilea drummondii in moist to wet garden soil. M. drummondii may be seasonally dormant. Spores develop in sporocarps on a stalk and were eaten by the Australian native peoples. However this plant provides another interesting case of fern toxicity as sporocarps contain thiaminase, an enzyme that destroys Vitamin B. Therefore, consuming this fern is not recommended. Photo credit: Bob Charlton.

Fern Society Membership

Membership is $12 for a person or household. Please renew now, for your enrollment through December 2018. Sign up at the April meeting or mail to

San Diego Fern Society
4780 Glen
La Mesa CA 91941

. Please keep the Fern Society up to date on your preferred mailing and email addresses and phone.


Fern Shows in 2018

May 26-27
Saturday and Sunday
Tropical Fern Show and Sale
Fairchild Tropical
Botanic Garden,
Coral Gables FL

June 9-10
Saturday and Sunday
LAIFS Fern Show & Sale
Los Angeles County Arboretum, Arcadia CA

August 18-19
Saturday and Sunday
San Diego Fern Society
Show & Sale
Casa del Prado Room 101
Balboa Park, San Diego CA

Other Events

For shows in Balboa Park,
visit the website:

For events at San Diego Botanic Garden in Encinitas:

The Amazing World in a Redwood Tree

Many Californians have visited the Coast Redwoods, the very tall trees
Sequoia sempervirens. Not to be confused with the giant sequoias of the Sierra Nevada mountains, the Coast Redwoods are known as the tallest whereas the Sierra trees are the most massive. The Redwood tree, both species, was designated as the official California state tree in 1937.

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Coast Redwood
Sequoia sempervirens in Henry Cowell Redwoods State Park, Santa Cruz County CA.

Coast Redwoods are found in areas near the ocean from extreme southern Oregon south into Monterey County. This is the Redwood tree considered here. These trees grow naturally from just above sea level to about 3000 feet elevation. Trees grow tallest in the fog belt, up to about 2000 feet elevation. The tallest living tree, named Hyperion and growing in Redwood National Park, measures 380 feet. All the tallest trees are in parks and preserves.

The taller Redwood trees are in deep valleys with year round streams and summer fog drip. Trees may absorb water directly from the fog through their leaves and bark. Also, the fog collects on the leaves and drips to the forest floor, providing a substitute for rain during the dry summer. Even though these trees grow in a rain forest, up to 30% of the water used by a Redwood tree may come from fog.

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Coast Redwood
Sequoia sempervirens at the San Diego Zoo. Above, the leaves and below, the bark on trunk. Photos this page credit: K. Russell.

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Beyond the impressive height and interesting habitat considerations, the coast Redwood tree provides a habitat of its own. Terrestrial animals such as salamanders, mollusks, earthworms and many insects, spiders and crustaceans live up in the trees among the mosses and epiphytic ferns. A variety of vascular plants grow in the trees, including Selaginellas, ferns, shrubs and even other trees. In one study of eight large trees (Reference 9), thirteen species of vascular plants were found. Shrubs and trees growing within the Redwood trees were often on dead, decaying wood. The ferns Polypodium glycyrrhiza and Polypodium scouleri grew on living branches. Polystichum munitum also grows in Redwood trees as well as on the ground. Polypodium glycyrrhiza has a dormant season similar to Polypodium formosanum, declining in summer and showing new growth around September. P. glycyrrhiza ferns were mostly on the lower branches. They have lanceolate fronds with pointed tips. Vaccinium ovatum, the California huckleberry, was also found in the Redwood trees. The sweet black huckleberry fruit was used by native peoples.

Polypodium scouleri  fair 20161
Polypodium scouleri, in a container hidden by mulch, shows the rounded pinnules. Here, it is at the San Diego County Fair 2016. Photos this page credit: K. Russell.

Polypodium scouleri is an evergreen fern of only coastal areas. It was the most abundant fern on the studied trees in Reference 9. It grows throughout the trees, although not always as strongly on the upper crowns where it may be affected by seasonal dryness. Researchers measured and studied all the mats of Polypodium scouleri on 27 Redwoods and also on 5 Sitka spruce (Reference 10). The selected trees were from forests along Boyes, Godwood, and Prairie Creeks in Prairie Creek Redwoods State Park and Mill Creek in Jedediah Smith Redwoods State Park. Here, five to eight feet of rain falls yearly.

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Complex branching and multiple trunks are seen in this Redwood
Sequoia sempervirens in Henry Cowell Redwoods State Park, Santa Cruz County CA.

The study was a major undertaking, requiring rope arborist techniques to climb throughout the canopy of these extremely large trees. Five of the studied trees are among the top ten tallest known Redwoods. Arborist researchers shoot rubber-tipped arrows trailing fishing filament over the branches, then pull nylon cord and then sturdy rope. The climbers can ascend and move laterally through the tree crown. In this manner they measured all the P. scouleri fern mats in the trees, recording depth of the mats, surface area, number of live fronds, maximum frond length and maximum number of pinnae per frond. Several mats were removed for further study. At the laboratory, these fern mats were broken apart to separate live fronds, dead fronds, live rhizomes, dead rhizomes, roots, humus, and debris. All samples were dried completely to determine dry mass.

The fern mats were found to have up to 192 kg of dry mass (400 pounds), 3 feet of humus depth, with over 2000 live fronds on the mat and some fronds up to 40 inches long and having 40 pinnae. These fronds are much larger than commonly found (See Reference 7 where fronds are described as having 2 to 14 pairs of pinnae and extending up to 16 inches.) It seems that along with the trees, the ferns are super-sized. These fern mats were sometimes huge, with very long fronds. (Compare photo, right, showing fronds having a few pinnae). The composition of the fern mats was primarily roots, humus and debris.

The trees selected for study had complex crowns, sometimes with multiple trunks. These massive trees supported up to eight species of vascular epiphytic plants. The highest estimated fern accumulation on a single tree was 1600 pounds of material, when dry. In nature the epiphytes on a Redwood tree are very wet, and in fact the tree grows roots into the humus fern mats, even up high. The mats of
P. scouleri are a likely contribution to other epiphytes and animals living in a Redwood tree. The study suggests that the epiphytic mass on old growth Redwoods exceeds that found on tropical rainforest trees. The fern Polypodium scouleri makes a major contribution to the old growth Redwoods.

1. Boyd, S & Griffin, J.R. 2012,
Sequoia sempervirens, in Jepson Flora Project (eds.) Jepson eFlora, ucjeps.berkeley.edu/eflora/eflora
2. Burgess, S.S. & Dawson, T.E. (2004), The contribution of fog to the water relations of
Sequoia sempervirens (D. Don): foliar uptake and prevention of dehydration. Plant, Cell & Environment 27, 1023-1034. doi:10.1111/j.1365-3040.2004.01207.x
3. Calflora. www.calflora.org/
4. Gymnosperm Database. www.conifers.org/cu/Sequoia.php
5. Hoshizaki, B. & Moran, R. (2001).
Fern grower's manual. Portland, OR: Timber Press.
6. Mickel, J. & Smith, A.R. (2004).
The pteridophytes of Mexico. Bronx, NY: New York Botanical Garden.
7. Munz, P. A. (1965).
A California Flora. Berkeley: University of California Press.
8. Pojar, J. (Ed.). (1994).
Plants of the Pacific Northwest coast. Vancouver, BC: Lone Pine Publishing.
9. Sillett. S.C. (1999). Tree crown structure and vascular epiphyte distribution in
Sequoia sempervirens rain forest canopies, Selbyana 20(1), 76-97.
10. Sillett, S.C. & Bailey, M.G. (2003). Effects of tree crown structure on biomass of the epiphytic fern
Polypodium scouleri (Polypodiaceae) in redwood forests. American Journal of Botany 90(2): 255-261.

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Kathie Russell's comments on Growing
Polypodium scouleri: Polypodium scouleri is a coastal fern found as far south as Santa Cruz Island near Santa Barbara and also Guadalupe Island, 150 miles off the west coast of Baja California, Mexico. Therefore it adapts to the San Diego area climate when water is provided. In addition to growing on trees, plants grow on rocks and practically in the salt spray of the ocean. Hoshizaki in Reference 5 suggests keeping P. scouleri in moist-dry well-drained mix or uncut moss with medium light.

Bart Keeran has grown
P. scouleri in a container for several years in his patio garden. I have also grown this fern (above) for quite a few years in a container in a semi-shady area. I purchased my Polypodium scouleri at Walter Anderson Nursery, and it was sourced from the grower Monterey Bay Nurseries. I included it in a display of California native ferns at the San Diego Fern Show. Just this winter I transferred my P. scouleri onto a slab of Redwood bark (above) with a bit of moss to keep it in place. My plant is certainly much smaller than those described on Redwood trees!

2018: The Year of the Garden

Plant a ferny container and pick up some repurposed garden stuff at the April meeting. Wide and shallow containers can provide the necessary good drainage. Ferns combine with other plants needing similar conditions to give the green garden a color interest.

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A container planted by Kathy Thomson for the San Diego County Fair 2017. Here, three small Pellaea falcata ferns are planted with blue lobelia. Pellaea falcata, a small to medium-sized fern, contributes dark green, somewhat glossy fronds to contrast with the small lobelia flowers. These plants both need medium to high light and moist-dry planting mix. P. falcata is a semi-hardy fern from Australia, New Zealand, India and islands. Photo credit: K. Russell.

Calendar 2018

April 19
May 17
Saturday, June 23
Lujan garden visit
July 19
August 16
Fern Show August 18-19
Saturday, September 22
Charlton garden visit
October 18
November 15
December 20
Annual Meeting

San Diego Fern Society Officers
President Kathy Thomson kmthomson@att.net
1st Vice President Paula Couterier
2nd Vice President Bart Keeran
Secretary Kathie Russell klrkath@yahoo.com
Treasurer OPEN
Board Members:
Bruce Barry
Bob Charlton kwyjibo@san.rr.com
Richard Lujan
Past President
Don Callard dcallard@san.rr.com

Webmaster: Bob Charlton kwyjibo@san.rr.com

Fern Society email

Bring $12 cash or check (payable to San Diego Fern Society) to a meeting or mail to: San Diego Fern Society
4780 Glen
La Mesa CA 91941

San Diego Fern Society was established in 1976 to provide a source of information on ferns; to arrange for people to study ferns together; to encourage the use and enjoyment of ferns in gardens, patios, and the home.

The Society aims to encourage all horticultural activities by example, education, and exhibits; to interest people in the beauty and satisfaction to be found in garden, patio and home living; to promote and stimulate interest in ferns; to encourage and develop culture of various types and varieties of ferns; to provide for the exchange and dissemination among Society members of information relating to culture of ferns.

Volume XXXXII, Number 4