Ferns are among the earliest land plants, with the oldest fossils dating back about 375 million years. Today’s ferns — an estimated 12,000 species around the world — link directly …
Ferns are among the earliest land plants, with the oldest fossils dating back about 375 million years. Today’s ferns — an estimated 12,000 species around the world — link directly to these ancient plants.
Ferns are vascular plants in the Pterophyta phylum, derived from the Greek pteridion, or little wings. They have roots, stems, and leaf-like structures called fronds.
Beyond these basics, ferns have some interesting botanical terms that help reveal the diversity of their forms. Stems can develop as rhizomes, which may be underground to help support the fronds. Rhizomes can be short, long, or erect and tufted. If you’ve never paid much attention to a fern’s rhizomes, it’s useful to note that short ones might indicate a clumping habit. Long ones signal a spreading ground cover, and erect or tufted rhizomes support a more upright, vase-shaped habit.
Once each frond begins to unfurl, it forms a crosier, commonly known as a fiddlehead. The frond consists of the blade, which is the leafy part, and the stipe, which connects the blade to the rhizome. The stipe is part of the rachis, the spine that stretches the length of the frond. Most ferns have compound leaves, with divisions called pinnae and further divisions called pinnules.
Unlike other vascular plants, ferns do not produce flowers or seeds. They reproduce by spores which are contained in structures called sori on the underside of the fronds. Most spores are dispersed by wind, and a small percentage will find suitable conditions to grow.
Ferns offer wildlife habitat — foraging resources, shelter, shade, and nesting materials for songbirds, amphibians, and beneficial insects. While ferns are a natural part of a woodland setting, they are an adaptable group, with species that thrive in dry shade, sunny rock gardens, and bog gardens.
Ferns are “knitters and weavers,” helping unite perennials, shrubs, and trees. They come in a range of hues — for example, the golden, copper, and russet colors on new fronds of the low-growing autumn fern (Dryopteris erythrosora). There’s a wide array of geometric patterns and sizes, from tiny ground covers to tree ferns reaching a height of 50 feet or more.
They can be part of a formal design or fill garden niches as ground covers or edging. Stumperies, fern tables, and containers are other creative ways to garden with ferns. The Elisabeth C. Miller Garden’s website offers instructions for building a fern table as well as other useful fern information: millergarden.org/.
The Pacific Northwest is home to many beautiful, tough, and adaptable native ferns and cultivars. Here are a few examples:
The native western sword fern (Polystichum munitum) grows in both dry shade and nearly all-day sun. Like other evergreens, it can manufacture food for itself year-round, and fronds remain green throughout the winter. Fronds can be pruned just before new growth emerges in spring, but is not necessary. The old fronds will decompose in place and provide resources for wildlife.
For sites with shade and more consistent watering during summer drought, the deer fern (Blechnum spicant) is one of our most beautiful native ferns. It is dimorphous, with separate sterile and fertile fronds. The evergreen sterile fronds reach outward, and the upright fertile ones are deciduous with narrower, less dense pinnae.
A favorite for heavy, dry shade is the evergreen soft shield fern (Polystichum setiferum). It’s a fully evergreen European cultivar. The Divisilobum group, with divided lobes, is called Alaska fern in our region. Bulbils, or small buds, are produced along the rachis and will root to form new plants.
A charming ground cover fern is the deciduous Western oak fern (Gymnocarpium disjunctum), a small Pacific Northwest native with a pale green color and an airy habit. Its long-creeping rhizomes help it ramble freely through woodlands or other shady spots.
It’s always a good practice to group plants with similar cultural and water needs. Our native salal (Gaultheria shallon), low Oregon grape (Mahonia nervosa), and western sword fern all prefer similar conditions. Hellebores, rhododendron, and cyclamen are good companions for shade-loving ferns.
Most ferns require little maintenance. Enriching the soil with compost, duff, or other organic matter is beneficial. When dividing or relocating ferns, the dormant season is the best time (usually late fall or winter). Leave foliage in place over the winter to provide protection and nutrients for root growth.
Pruning old fronds isn’t necessary for plant health, but can be done for aesthetics. The Hardy Fern Foundation offers information on when to cut back different types of ferns as well as a fern database and propagation tips. Look under the “Fern Info” tab: hardyferns.org.
Ferns appear in myths and legends nearly everywhere they grow, from the tropics to high mountains to temperate rainforests. In many cultures, ferns had special significance during the summer solstice. “Invisible” fern seeds or rare fern flowers could herald good luck, prosperity, or magical powers. The fresh foliage signified new life, family, and hope for future generations. The summer solstice is a perfect time to enjoy the abundance and diversity of our Pacific Northwest ferns.
The Jefferson County Master Gardener Foundation’s Secret Garden Tour is June 18. For details and ticket information, visit jcmgf.org/secret-garden.
Barbara Faurot is a Jefferson County Master Gardener and Master Pruner, working with other volunteers who serve as community educators in gardening and environmental stewardship.
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