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Landscaping With Ferns

by Nancy Swell

Ferns, all the rage during the Victorian era, were forgotten for decades. Today, natural landscaping is the hottest trend in gardening since the English-style herbaceous borderr, and these wildlings are making a comeback. Yet ferns have a place in almost any kind of garden. In traditional formal gardens, ferns are perfect as groundcovers, foundation plantings, accents, specimen plants and underplantings for shrubs. Ferns are a natural element of the woodland garden. Here is found the partial shade, wind protection and increased humidity that enables most ferns to thrive. Indeed, woodlands are the natural habitats of many of our ferns. For world-weary humans, woodland gardens provide a quiet retreat from the stresses of everyday life.

Woodland Gardens

If you want to recreate a patch of native forest in your yard or embellish a remnant that's already there, select ferns indigenous to your area. At a minimum, select species suited to the conditions in your garden. Broad and narrow beech ferns, oak fern and polypodies are graceful ground covers, wandering happily through the humus-rich litter of the woodland floor. These are not for accents; they don't stay where they're put, but rather naturalize quickly to create a delightful unplanned effect. New York and hay-scented ferns not only wander but also tend to take over their area. They are most useful in larger areas where there are no delicate treasures to be overgrown.

Ferns as Accents

Consider using some strong growing accents along woodland paths to help lead the eye from one place to another. Most of the dryopteris can be used for this purpose; good choices include the majestic Goldie's fern, the dark-leaved autumn fern, the blue-green, vase-shaped marginal woods fern and the varied forms of the male fern. The elegant maidenhair is a must-have. The evergreen Christmas fern, the soft shield fern and the tassel fern are lovely evergreen ferns. Add to this list the Japanese painted fern with its bright variegated foliage, and you can create an unforgettable picture. Any or all of these can also be used in a shaded flower Border with good soil and adequate moisture. They provide interesting texture and unifying shades of green to the border. Use the vigorous lady ferns with caution. Most of their ruffled, fringed or otherwise modified cultivars are less invasive and very interesting in their own right, though they may be a bit exotic for a naturalized effect.

Streamside Gardens

If you're lucky enough to have a stream running through your property, or if you can develop a moist area near a pool, the decorative possibilities of ferns are exceptional. Here you can grow the large and stately royal fern, the cinnamon fern and the ostrich fern. With enough water, these grow big, and this must be taken into consideration. The ostrich fern also spreads by runners and can outgrow its area unless it is restrained. Sensitive fern and the Virginia chain fern may also overstep their bounds under these conditions. As long as there is good drainage, any of the woodland ferns are also suitable for streamside or poolside plantings. In fact, they tend to grow bigger and better with the extra water. As usual, maidenhairs are essential. They are the true grace notes of the garden.

Rock Ferns

Try fitting some of the smaller ferns into the crevices in, on or along walls and steps. These specialized ferns require extra drainage and may need to be isolated from larger or faster-growing plants. If mortar has been used, ferns preferring an alkaline soil are the best choice. Walls often create a microclimate that enables you to grow ferns that are only marginally hardy in your area. Particularly appropriate are the spleenworts, polypodies, lip ferns and perhaps the cliff brake. English hart's tongue (much easier to grow than our American native) is a memorable sight when planted in walls and steps.

Any of the accent ferns recommended above for use along woodland paths can be planted against a rock or boulder or wall to catch the eye and trace an interesting pattern against its background.

Ferns in Containers

There are many reasons to grow hardy ferns in containers. A plant in a container is portable. It may be placed wherever an accent or garden feature is needed, regardless of soil conditions. Plants in pots are often essential in paved areas such as patios, and are just as useful where tree root competition makes it next to impossible for anything to grow. Pots submerged in mulch beds can be used for variable displays. These are particularly effective around garden pools. Another advantage is that less hardy varieties can be used in the displays during the growing season, then protected over the winter. Ferns in pots can temporarily fill in blank spots in the flower border. Pots can also be placed on pedestals, hung from trees or perched on fences.

It is much easier to meet the special requirements of some ferns if they are isolated in a container. Lip ferns need a quick-draining acidic soil and more light than most ferns. Cliff brakes need bright light and an alkaline soil. Most of the small aspleniums, including the walking fern and its hybrids, need a soil that drains well but holds moisture. More than anything else, the aspleniums need protection from slugs and snails and from competition from larger plants. You can create small rock gardens in hypertufa troughs (rustic, porous containers made of peat, perlite and Portland cement). These make attractive display gardens for the smallest of the ferns, and the location and planting mix can be adjusted to meet any requirements.

The best potting mixes are based on either loamy soil or soil substitutes such as peat moss or pine bark. No matter what type, a mix must be compact enough to hold the plants in position, free draining but moisture retentive, fertile and open enough so that air can reach the roots. Potting mixes must not carry disease, weed seeds or pests. Choosing soil mixes is not an exact science; there are probably as many mixes as there are growers and gardeners, each of whom modifies his basic mix according to the requirements of the species being grown.

The following is a typical soil-based mix:

One part good garden soil
One part coarse washed sand
Two or more parts organic material such as peat moss, composted leaves or fine pine bark.

If you start with a good loamy soil, this mix will grow the best plants of all. The two major drawbacks of soil-based mixes are the difficulty in finding good soil and the need to sterilize it. Sterilized soil is especially important for sporelings and young transplants. For lime-loving ferns, add one ounce or more ground limestone per cubic foot of soil mix. If you have difficulty finding coarse sand, you can use "starter grit" found in feed stores.

The following are soilless mixes based on peat moss:

One part sand
One part peat moss

For a lighter mix, try:

Two parts peat moss
One part vermiculite
One part perlite

Potting mixes for ferns can also be based on pine bark. Start with a finely ground bark (it should pass through a 1/2-inch sieve) that has been wet down and composted for about a month. After composting, mix as follows:

Three parts bark
One part coarse sand
One part peat moss

Soilless mixes must have all nutrients added to them, including micronutrients. To three cubic feet of mix, add five ounces of a slow-release fertilizer, one ounce of superphosphate, two ounces of lime, two ounces of gypsum and 1-1/2 teaspoons of micronutrient.

If you buy an already prepared potting mix, make sure it has the qualities listed above.

Plants in containers may need to be fed more often than plants in the ground because frequent watering causes most nutrients to leach out of the soil. Use soluble fertilizer at half the strength recommended for other house plants. Make sure that the potting mix drains freely to avoid salt buildup.

Nancy Swell grows and propagates a wide variety of hardy ferns in her garden in Richmond, Virginia. She is an active member of The American Fern Society, The British Pteridological Society and The Hardy Fern Foundation and is a self-proclaimed fern fernatic.