May 2018

May 17 Fern Society

This month we welcome Michael Ludwig, presenting on Companion Plants with Ferns, 7:30pm Thursday, May 17, Casa del Prado Room 101, Balboa Park. Michael's specialty is begonias and he is very active in begonia organizations. He also grows a wide variety of botanical treasures including Platyceriums and many other ferns. Those who have visited his shadehouse know that he is a talented horticulturist. He is always gracious in sharing his experiences of growing plants here in San Diego.

Fern growers generally enjoy a variety of other plants along with their ferns. Designing with several types of plants enriches the garden and patio and creates a pleasing environment.

This month the society plans to have some small ferns on the Plant Table at modest cost. Sales are in cash.

San Diego County Fair

Work days for the Fern Society exhibit are Saturdays May 12 and May 19. The exhibit must be essentially completed by May 19, with botanical names of the plants ready for the required signage. If you bring plants for the display it is very important that Kathy Thomson or Kathie Russell record the botanical names, and common names if appropriate. Our exhibit is entitled, A Sweet Retreat. This coordinates with the Fair theme, How Sweet It Is, and the Garden Department focus on Living the Sweet Life.

Report on April Fern Society

In April attendees enjoyed the Spring Garden Sale. This popular sale provides a great opportunity to buy and sell garden items and plants between Fern Society members.

Kathy Thomson discussed container planting for ferns, and there was a demonstration of mounting a Platycerium pup. Those in attendance had the opportunity to plant a fern container to take home.

Xeric Ferns

Since everyone seems to know that ferns need water, the concept of drought-adapted ferns can be a bit hard to grasp. In San Diego County we have several species of ferns growing in the desert. However in our gardens the rule might be stated: no water, no ferns. The popularity of water saving in the garden and of using drought tolerant plants does not seem compatible with growing ferns.

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Astrolepis sinuata growing in a container with a sun garden ornament to signify that it grows in full sun. This fern is native to Arizona, but is often available in local nurseries. It can dry with fronds rolled inward, and then come back with water. Photo credit: K. Russell.

The xeric ferns, also called xerophytic ferns, do not directly give us a garden in the tropical paradise style. San Diego gardeners want to retain their Platycerium ferns, tree ferns and various beautiful tropical and subtropical fern varieties and companion plants. Fern growers choose to budget some precious water for plants. Comments from Fern Show and San Diego County Fair guests indicate that ferns enhance a peaceful and serene environment. In the Fern Society exhibit at the Fair this year, the design for A Sweet Retreat will use mostly ferns.

In contrast to the well watered fern garden, growing xeric ferns may not gain attention from friends but will certainly impress members of the San Diego Fern Society. Planting and care of xeric ferns is generally different from other ferns. It is important to research these plants and their environments. Most of the ferns in the desert have roots stretching back under rocks, which enhances collection of needed moisture. Often these plants are summer dormant when there is no summer rainfall. Some have fronds which curl up in dry times and open out again with moisture. Desert areas often have late summer rainfall, so a little watering of these ferns in the San Diego area garden may be important.

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Midella fallax in a sunny area in the garden of the late Robin Halley. Below: Acrostichum bonariense, formerly known as Cheilanthes bonariensis. David Schwarz assisted Robin in preparing this garden xeric area in La Jolla a few years back. Photo credit: K. Russell.
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Sue Olsen recounts her amazement at seeing xeric ferns growing in a remote Arizona dry gulch. Although she resides in the moist, ferny habitat of western Washington State, she chooses to grow Cheilanthes ferns, using a mix of well-washed pumice, bark and granite grit with a little loamy compost. She locates the containers where air circulates, in full sun but under eaves to protect from excess winter rain. In summer the plants are protected with light shade and receive water as needed.

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Cheilanthes eckloniana, a fern from South Africa, growing in Berkeley Botanical Garden. Photos this page credit: Bruce Barry.

The northern California Berkeley garden, according to website information, has found xeric ferns to be quite adaptable and suggests that they have potential for Bay Area landscapes. For use in the garden they recommend porous, well-drained soil, with bright light and good air circulation.

Fern Grower's Manual by Hoshizaki and Moran informs us that most ferns in the genera Actiniopteris, Astrolepis, Cheilanthes, Doryopteris, Notholaena, Pellaea and Pityrogramma can be considered xerophytic. Since the time of publication, many Cheilanthes ferns have been transferred to the genus Myriopteris, so these ferns are also xeric. Some xeric ferns are considered challenging to grow. The authors suggest planting xeric ferns in bright but indirect sunlight, or up to full sun in coastal areas. Soil should drain well and be kept lightly moist. A simple mix suggestion is one part leaf mold or peat moss and two parts gravelly sand. The plant crown should be slightly above soil level.

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Myriopteris lindheimeri, formerly called Cheilanthes lindheimeri, also growing in Berkeley Botanical Garden. This fern is found in Arizona.

A rock garden is ideal to showcase xeric ferns. The Astrolepis, Cheilanthes, Myriopteris, Pellaea and Pityrogramma ferns are recommended for rock plantings. Rock walls and gardens are traditionally planted with smaller ferns and compact fern cultivars. Most spreading ferns will overrun their assigned place, so require frequent trimming or dividing if used. Planting in a loam soil or potting mix is suggested, along with coarse sand. Good drainage is important in the rock garden. The larger decorative rocks should be set in after the planting mixture is in place. Small rocks can be used to keep the ferns securely planted and the soil surface can have gravel or small stones to protect from erosion. Suggested rock garden ferns for the San Diego area include Polypodium scouleri, Astrolepis sinuata, and Cyrtomium falcatum 'Maritimum', a mini variety of Holly Fern. Some of the Pellaea and Cheilanthes species also are worth consideration.
Resurrection Plants

Some plants can dry out to the point of seeming dead. These plants become dry, withered and brown when water is not available. Botanists use the term, resurrection plants, to refer to a group of some 130 flowering plant species which appear to come back to life after desiccation. There are plants whose water content fluctuates with changes in air moisture and metabolism ceases in drought. Other types of plants would die in these drought conditions. Some of these plants lose chlorophyll during drying, and others retain it.

Selaginella lepidophylla is sometimes called the Resurrection Fern. A Selaginella and not a true fern, this plant is semi-hardy and native to the southwestern US and Mexico. Plants tolerate high light and grow best in moist-dry conditions with good drainage, to about four inches tall. The plant curls into a ball when dry, then opens out to a flat rosette with water. The inner leaves roll up in a fiddlehead spiral while the outer leaves curl into the shape of the letter "C" around them.

Selaginella lepidophylla. Photo credit: Kristian Peters, Creative Commons.

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Selaginella lepidophylla when dry. Even a dead plant can absorb water and open, so purchasing a dry plant is suggested only as a diversion, as it is unlikely to live. Photo credit: Riki, Creative Commons.

The Resurrection Fern Polypodium polypodioides commonly grows on tree trunks in the southeastern US. Other varieties of the same fern are found in Central and South America as well. Plants grow slowly and are difficult to establish in cultivation, and require acidic conditions. In nature Polypodium polypodioides is common in the Gulf States on live oak trees. Studies show that this fern can lose up to 97% of its water and survive. Plants may continue for months in the drought condition, and then rehydrate with rain. The protective outer scales absorb water quickly. In a few minutes the fronds are restored to function and seem undamaged.

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Polypodium polypodioides growing on an oak tree in South Carolina. This fern may establish massive growth on trees, especially the oak Quercus virginiana. Below: Closer view showing partially dried fronds. Photos credit: Kathy Thomson.
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1. Grusz, A.M. & Windham, M.D. (2013). Toward a monophyletic Cheilanthes: The resurrection and recircumscription of Myriopteris (Pteridaceae). PhytoKeys 32: 49–64 (2013). doi: 10.3897/phytokeys.32.6733
2. Hoshizaki, B. and Moran, R. (2001). Fern grower's manual. Portland, OR: Timber Press.
3. Kessler, M. & Siorak, Y. (2007). Desiccation and rehydration experiments on leaves of 43 Pteridophyte species. American Fern Journal 97, 4, 175-185. doi 10.1640/0002-8444(2007)97
4. Olsen, S. (2007). Encyclopedia of garden ferns. Portland, OR: Timber Press.
5. Ryan, J.C. (2017). A Comparative literary history of resurrection plants. Comparative Literature and Culture 19.1.
6. Steffen, R., & Olsen, S. (2015). The plant lover's guide to ferns. Portland, OR: Timber Press.
7. University of California Botanical Garden at Berkeley.

Unusual plants, hiding in the garden

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Shown here in Michael Ludwig's shadehouse is Anemia mexicana. This fern is native to Mexico and the Edwards Plateau in Texas. It grows on limestone outcrops from just above sea level to 6000 feet elevation, in light shade. Note the distinct fertile pinnae. Photo credit: K. Russell

For Spring Planting

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Adiantum capillus-veneris 'Banksianum' available at Walter Anderson Nursery, May 2018. Photo credit: K. Russell
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LAIFS Fern Show & Sale
June 9-10

Saturday 9:00am - 4:00pm Sunday 9:00am- 4:00pm

Los Angeles County Arboretum

301 North Baldwin Avenue, Arcadia CA (one block south of the 210 Freeway)

2018: The Year of the Garden

Doodia media is an underutilized garden fern, perhaps because the common name, Hacksaw Fern or Rasp Fern, does not bring peaceful garden thoughts. This lovely small fern may decline in winter but returns year after year, and gives a reddish color to the fern garden. Tolerant of bright light or sun, this plant needs just modest water and may be grown in a rock garden. It is native to Australia, New Zealand and islands.

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Doodia media reappears in late winter in a San Diego area garden. It spreads slowly and is easily contained. Photo credit: K. Russell.

San Diego Fern Society Officers
President Kathy Thomson
1st Vice President Paula Couterier
2nd Vice President Bart Keeran
Secretary Kathie Russell
Treasurer OPEN
Board Members:
Bruce Barry
Bob Charlton
Richard Lujan
Past President
Don Callard

Webmaster: Bob Charlton

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

The 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 5