A deer fern, scientific name Blechnum spicant, is one of 18 species of the group known as hard ferns. It is a semi-evergreen perennial native to North America and Europe and has been naturalized across most of the world. The deer fern has two types of glossy green leaves and large numbers of sori. It has a moderate to rapid growth rate. This species can tolerate a wide range of conditions and is relatively easy to grow and maintain.
Hard ferns, members of the genus Blechnum, are characterized by their tough, leathery leaves with a distinct glossy sheen. A deer fern grows in dense clumps and spreads outwards via rhizomatous growth. This is a method of asexual reproduction in which the plant produces a number of underground trailers called rhizomes. The rhizomes tunnel through the soil away from the parent plant and send new shoots through the soil surface. These shoots develop into replicas of the parent plant; once they begin to mature, these offspring put out their own rhizomes.
This species produces both fertile and sterile fronds, or leaves. Sterile fronds are usually shorter and paler in color. Fertile fronds are longer and usually stand more erect. These plants are classed as semi-deciduous; only the fertile fronds are deciduous and fall away during late autumn, whereas the sterile fronds are evergreen and live through the cold weather. On the underside of the fertile fronds, masses of sori are produced.
In relation to ferns, sori are small mounds which contain huge numbers of sporangia. Sporangia are tiny sacs which contain large numbers of spores released as they mature. The spores are the equivalent of seeds and create new plants.
The deer fern is tolerant of a wide range of conditions and is therefore reasonably easy to grow for even an inexperienced gardener. Able to cope with a wide pH range of 5.5 to 7.5, this species can grow in almost any soil type providing the soil is moist and has good drainage. It is often grown in exposed locations because it rarely suffers any damage from wind and weather.
This plant cannot tolerate long periods of drought, however, and is unable to cope if exposed to temperatures below -5° Fahrenheit (-20° Celsius.) If the deer fern is exposed to these extreme temperatures without any protection, it will die. To offer some warmth and protection, the deer fern can be covered with gardening fleece, and mulch can be deeply piled around the base to keep the temperature at safe levels.