July 28, 2012
These past few months, I have been on a steep learning curve regarding ferns. I have to admit, I have always thought of ferns as lovely companion plants — fillers — something green and frilly to add to a bouquet or display as a house plant. I have been humbled as I learned about the history and culture of this plant species.
What piqued my interest in this mainstay of gardens, woodlands and floral arrangements? "Plantosaurus Rex," the current exhibit at San Francisco's Conservatory of Flowers, traces the history of plants during the age of the dinosaurs. Ferns were among the very first plants on earth — and food for some dinos.
More than 360 million years ago, ancestors of our recognized ferns existed on earth and fossils have allowed us to research their history. It is believed that there were more than 125,000 species thriving in the Carboniferous era. Ferns dominated the earth, some of them growing hundreds of feet tall.
One of the conservatory's nursery specialists, Lupe Cota, along with a docent, Mary Dee Beall, presented an informative evening on ferns in the exhibit. I was fascinated and found myself with a new appreciation for the ferns in my garden and beyond.
Today, there are some 12,000 named species in the family Pteridophyta. Ferns are identified as plants that reproduce by spores and have neither flowers nor seeds. Ferns have roots, stems and leaves and a well-developed vascular system that moves food and water through the plants.
I have thought of ferns as water and shade loving plants. It was interesting to discover that they can be found in all parts of the world. There are desert ferns as well as ferns near the Arctic Circle. They range in size from tiny plants growing in rock crevices to more than 50-foot-tall tree ferns.
One of my very favorite ferns is the bird's nest variety. I adore the thick, vigorous, shiny green leaves, extending from a central core. I have blindly accepted the bird's nest as a fern and never paused to ask myself: why is this fern leaf solid — where are the little fronds like the ones on other ferns? Why do the delicate maiden hair ferns have multiple separated leaves?
Here are a few terms I have added to my vocabulary:
- Rachis: axis or central stalk of the leaf
- Simple leaf: a leaf with a single blade, not divided
- Pinnate: leaflets arranged along each side of the axis
- Bipinnate: divided once, then each division divided again
- Tripinnate: three times pinnate
My garden is populated with dozens of perennial ferns that have naturalized over the years. I can't think of a day when I can't go out and find some type of fern to add to a cut flower bouquet. I also have been taking them for granted.
Fiddleheads are the tightly coiled new leaves that gradually unfurl as the leaf matures. Fiddleheads of Ostrich ferns are considered a culinary delicacy, available for only about three weeks in early spring. Not all fiddleheads are edible, so purchase them from a reliable source or take a fern expert with you when gathering, much as you would when hunting for mushrooms.
Other than the use of ferns in the landscape and floral industry and the occasional fiddlehead sauté, ferns do not offer much current economic value. Their true value lies in their fossilized form in vast beds of coal, created over millions of years.
Another plant I have in my garden is the commonly known "asparagus fern," which is not really a fern at all. It is in the lily family. If you have grown an asparagus fern for a while, you have probably noticed occasional red berries. Ferns do not produce flowers or fruit.
To see more magnificent ferns and learn about their existence in the Mesozoic Era, visit "Plantosaurus Rex" through Oct. 21 at the Conservatory of Flowers.
Ferns are a great asset in our Mediterranean climate. There are numerous California native ferns that are quite easy to establish in our gardens. I have lovely lady ferns that emerge every spring and require minimal maintenance beyond removing dead fronds. Best of all, ferns are commonly ignored by our local deer population (although we know there is an occasional tasting of even the most deer-resistant plants) Once established, ferns can be quite drought tolerant.
Sword ferns growing under my oak tree never receive supplemental water yet appear healthy and hardy, year after year. For a list of ferns that grow well in our area and other water-wise plant selections, visit the Marin Master Gardener website and click the Water-Wise Plant Selection Guide link.