by Dina Lehmann-Kim, Master Gardener
While the Shade Garden at Bon Air Park is host to a wide variety of plants, the stars this month are the ferns. Ferns thrive in shade and come in a range of sizes, hues, and leaf (frond) structures. This standout plant has prehistoric roots and continues to enchant gardeners despite the fact that it does not flower.
Fast-spreading ferns can be used as a ground cover while slow-spreading or “clumping” ferns such as the garden’s Japanese painted fern (Athyrium niponiscum ‘Pictum’) are best used as an accent plant in a well-defined space.
Freely spreading ferns are useful for covering large areas and can provide a consistent look and feeling throughout a particular section of a garden. Those with feather-like fronds such as the garden’s hay-scented fern (Dennstaedtia punctilobula) can enhance a garden’s landscape design by imparting an airy, ethereal feel. This fern’s placement in the Shade Garden mimics how it is found in the wild—among boulders and on hillsides. This species can tolerate sun and can reach up to two feet in height. It should not be placed in a small area unless it is thinned regularly.
The garden’s Christmas fern (Polystichum acrostichoides) thrives and fills larger spaces just as easily as it grows in small nooks and crannies. This fern retains some of its green color throughout the colder months (hence its name) allowing gardens to maintain some color during the winter season. It is a slow-spreading fern, reaches two feet in height, and tolerates a variety of growing conditions.
Three other ferns grace the beds of the Shade Garden: Interrupted fern, northern maidenhair fern, and royal fern. Each lends its unique characteristics to the garden. Interrupted fern (Osmunda claytoniana) derives its name from sporangia, the spore-bearing tissue which appears on the stem in between the two leaf blades. It is native to the northeastern US, tolerates very cold conditions, can reach four feet in height, and grows well in partial sun/light shade, making it a good choice for Northern Virginia gardens.
The Shade Garden has a single specimen of northern maidenhair fern (Adiantum pedatum), another fern native to North America. This plant arranges its shiny, black-stemmed fronds in a semi-circular pattern. It prefers full shade (eight hours or more), can reach up to two feet, and spreads very slowly, forming clumps over time. Though it prefers warm summers, high temperatures may cause fronds to brown, particularly if soil moisture is not maintained or if it gets too much sun. Its frilly fronds dance about at the slightest breeze and make it a lovely ornamental addition to any shade garden.
Of the garden’s ferns, the royal fern (Osmunda regalis) is perhaps the most unusual. In full sun, it can reach six feet (but three feet in shade), has a bolder leaf pattern, and produces large clusters of spores. Other ferns typically do not withstand as much sun. Most ferns produce spores on the undersides of their fronds; the royal fern derives its name from its regally upright growth habit, with the spores at the tips of the fronds, looking almost like flowers. Like most of the ferns growing in the Shade Garden, it too is a native of the American northeast. It is considered easy to grow and can tolerate a variety of soil and temperature conditions.
A midsummer visit to the Shade Garden will provide residents of northern Virginia a good idea of how this assortment of ferns can be used in their own home gardens.
More about ferns from MGNV – Tried and True Native Plant Selections for the Mid-Atlantic
- The Plant Lover’s Guide to Ferns, Richie Steffen & Sue Olsen, Timber Press, 2015
- Missouri Botanical Garden Web site – http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=j200