Ferns: Outdoors and In

Mar 04, 2015

by Dale Odorizzi, Lanark County Master Gardeners

Nothing says a woodland garden better than a stand of beautiful, delicate and graceful ferns.

Ferns are plants that produce evergreen or deciduous leaf-like structures called fronds. In our part of the world there are close to 20 species of ferns growing wild in our woods. The most popular at garden centers are Ostrich Ferns and Maiden Hair Ferns. If you have a Bog Garden the Sensitive Fern grows happily in moist to wet soil.

Ferns provide garden interest. Most uncurl bright foliage in the spring. The fronds of deciduous plants start fading in the late summer and die back after the first frosts.

If you wish to grow ferns in your woodland garden, you will need partial to deep shade and damp soil. A good layer of mulch keeps them growing and expanding. Once established, ferns do not require much maintenance.

The one fern to beware of is the Bracken Fern. It is a coarse perennial that grows to one metre tall and spreads by underground rhizomes. Once you get it in your garden, it will take over. This is a much hated plant by rock garden enthusiasts.

Ferns do not flower, and reproduce by spores rather than seeds. Their spores are mostly borne clustered on the underside of their fronds. After germination, spores form green tissue where both male and female reproductive parts are seen. Ferns are valued for the beautiful shape of their fronds. Sometimes foliage is green and some species have displays of red, yellow or gray. Fronds may also have brown scales at their bases or have silvery coloured undersides.

As well as brightening up your shade garden, ferns are also commonly used as houseplants. In Victorian times, they were extremely popular and large collections were grown in conservatories and specially constructed glass cases. These prefer bright indirect light.

Most ferns cannot tolerate hot, dry air and prefer high levels of humidity. Most ferns are not really difficult to grow but they will not tolerate neglect. The compost must never be allowed to dry out and the surrounding air needs to be kept moist.

There is a bewildering choice of species, as nearly two thousand are suitable for growing indoors but only a few are available commercially. The Boston Fern is one that is readily available and is large enough to make a statement when planted on its own. Boston Ferns are long living and are frequently passed from generation to generation. Smaller, delicate ferns, such as the Delta Maidenhair, are best planted in a terrarium.

Some secrets for success are to maintain an average warmth, cool but not cold, 15-20ºC.

Unlike their native cousins, indoors, ferns are not shade lovers. Most originated in the tropics and thrive in indirect light, such as an east or north windowsill. Compost must be kept moist and never allowed to dry out. Moist air is necessary so spray the plants regularly or sit the pots on a tray of pebbles with water added. Repot in the spring when the roots fill the pot and do not bury the crown.

Whether you add a fern to your indoor or your outdoor garden, you are sure to enjoy these wonderful plants.

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