Home > Great Big Greenhouse Blog > July 2015 > The Great Indoors-Ferns

The Great Indoors-Ferns

Ferns are very old plants, appearing in the fossil record over 300 million years ago, long before the dinosaurs.  There are over 10,000 species of ferns, displaying wonderful diversity in leaf shape, color, size, texture, and habit.  The word “fern” is from the old Anglo-Saxon fearn, meaning feather.  The uncurling new fronds of ferns resemble the scroll at the top end of the neck of a violin or fiddle.
Although ferns and their allies (mosses, lichens, etc.) are the only plants that do not produce flowers, they are highly desirable for their beautiful foliage.  With a distribution world-wide in a variety of environments from the Artic to the equator, there are tiny moss-like ferns, as well as eighty-foot tall tree ferns. Within this wide range of ferns, there are many suitable for use as houseplants, some of which make wonderful specimen plants while others add charm and softness to container gardens.  All indoor ferns can be used outside in warm weather to turn shady porches, patios, and decks into green oases.
Ferns gained their popularity as indoor plants during the Victorian Era.  The Victorians took their fads seriously, and so a fern “boom” took place, with ferns in the garden, in the house, and especially in the conservatory.  Beautiful old prints and photographs from this era show botanical gardens displaying exotic tree ferns and almost mystical shady ferneries.
Ferns reproduce by spores rather than seeds.  Most of us are familiar with the interesting arrangements of sporangia along the undersides of fern leaves.  We frequently receive phone calls from customers concerned about the tiny brown insects on their ferns.  If they form a discernable pattern or are evenly distributed along the leaf, you have spores—insects are not inclined to line up like little soldiers in formation.
Like all life forms, the earliest ferns were water dwellers, and ferns still require water in order to reproduce.  When ready, the sporangia release the spores which drop onto the soil below in what appears to be a fine dust.  The spore germinates and becomes a prothallus, which then develops male and female organs which in turn produce sperms and eggs.  When a drop of water is available to it, the sperm swims to the egg, and they unite and form a zygote which develops into the new fern.
One of the most popular indoor ferns is the Rabbit’s-foot fern (Humata tyermannii), with its fuzzy white rhizomes (creeping or climbing stems) that crawl over the edge of the pot.  If you don’t catch it in time, the rhizomes will completely encircle the pot, making it very difficult to repot the plant.  Other nice “footed” ferns include Deer foot (Davallia fejeensis ‘Major’), Lacy Hare’s foot (D. fejeensis ‘Plumosa’), and Squirrels’ foot fern (D. trichomaniodes, also Brown Rabbit’s foot.)  Other ferns grown for their interesting rhizomes are Kangaroo paw (Microsorum diversifolium), E.T. fern (Polypodium formosanum), and Possum Tail fern (Scyphularia pycnocarpa).  Beautiful feathery or smooth green fronds arise from the rhizomes of these mostly epiphytic ferns.  Epiphytes are plants that grow up in trees but are not parasitic.  These plants are taking advantage of light that is more abundant in the branches than on the forest floor.
The Boston fern (Nephrolepis exaltata ‘Bostoniensis’), while still the most widely used fern, has some competition in other Nephrolepis ferns, including Kimberly Queen fern (N. obliterata) and the Macho fern (N. biserrata).  These ferns are difficult inside in the winter, but can be kept over if desired since they are not winter hardy here.  Bright light and cool temperatures are required.
Among the most beautiful of ferns are the many Maidenhair varieties (Adiantum raddianum and others), with their delicate, lacy fronds.  They require a bright situation with good air circulation, and must be kept moist, avoiding water on the foliage.  Also popular and quite beautiful are the Birdsnest ferns (Asplenium species and cultivars).  These rainforest natives have evolved to catch leaf litter and insect and other animal poop in the central tussock as their fertilizer, and this circular, symmetrical growth habit makes them an ideal specimen plant.
There are many more ferns suitable for indoor use, but I have to mention the Staghorn fern (Platycerium species and cultivars).  These striking ferns grow up on the trunks and branches of trees, with a sterile frond known as a “shield frond” covering the roots and providing a place for the plant to capture tree and animal litter for nutrients, while a fertile frond produces spores for reproduction.  This fertile frond earns the plant its common name by resembling a rack of antlers.
Ferns with a leathery, as opposed to a papery, leaf tend to better handle dry indoor air.  While everyone loves the look of the magnificent tree ferns, these plants are extremely difficult to keep inside due to their high humidity requirement.  They do, however, make a nice summer annual for a shady spot in the garden or on a porch.  Keep them wet. 
Most ferns fare better inside if the temperatures are a little on the cool side (60-70 degrees), especially the Boston and other Nephrolepis.  While ferns like moisture, good drainage is essential to prevent water-logged soil.  Apply a dilute solution of a high nitrogen fertilizer (e.g., 10-5-5) regularly from March through September.  Repot ferns as needed in the spring.
TIP:  A tired, pale, or lackluster appearance of an indoor fern can usually be reversed by a period of outdoor rest and recuperation.  Place the pot in a shady, sheltered location in warm months, and let the fresh air and rain rejuvenate the plant.
Posted: 7/24/2015 by Margot | with 0 comment(s)
Filed under: ferns, Great, Indoors, Margot, The
Blog post currently doesn't have any comments.
 Security code