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A History of Landscaping Indoors
by Scott D. Appell
In the beginning, there was light—but there was no glass. The trial and error task of mastering the art of glassmaking was, by far, the most important factor enabling the cultivation of plants indoors. Before people learned the secret of glassmaking, which entails fusing sand (silica) with soda (sodium oxide) and lime (calcium oxide), nature made glass in two different ways. When lightning strikes sand, the heat sometimes fuses the sand into long slender glass tubes called fulgurites—commonly referred to as petrified lightning. And the intense heat of volcanic eruption sometimes fuses rocks and sands into a glass called obsidian.
Historians do not know exactly when, where, or how people first learned to make glass, but it is generally believed that it was first manufactured sometime in the 3000s BC. Early glass manufacture was slow, and it required hard, hot work. Glass blowing or glass pressing were unknown and furnaces were small and lacked sufficient heat for proper melting. Glassmaking was such a costly enterprise that the ancient Egyptians relegated glass to jewelry making—achieving dazzling colors by adding metallic oxides to a basic recipe.
Starting in the 17th century, newly discovered flora arrived in Europe from all over the world aboard the trading vessels that crisscrossed the oceans. Orchids, pictured above, palms, camellias, aroids, sansevierias, and cacti were among the many plants that found their way into European glasshouses. [Photo: Alan & Linda Detrick]
Climate Control
The construction of artificial climates for plants is first alluded to in 500 BC Greece, in reference to the "Gardens of Adonis" (which were probably early precursors to cold frames). In his work Phaedo(n), Plato remarks: "A grain of seed, or the branch of a tree placed in or introduced to these gardens, acquired in eight days a development which cannot be obtained in as many months in the open air."
In the first century AD, the Roman Columnella, who wrote about gardening and agriculture in his work De Re Rustica ("About All Things Rural"), describes the cultivation of cucumbers in large, covered containers (ingeniously piped with hot water). "It is also possible, if it be worth the trouble, for wheels to be put on to the larger vessels so that they can be brought out with less labor. In any case, the vessels ought to be covered with slabs of transparent stone, so that in cold weather when the days are clear, they may be brought into the sun. By this method Tiberius Caesar was supplied with cucumbers during almost the whole year."
The aforementioned "transparent stone" was lapis specularis (according to Pliny and Seneca), the complex silicate now commonly called mica. This mineral forms in thin, flexible, transparent or translucent layers, which are easily separated.
It was in 50 AD that the first window glass was manufactured. This paved the way for the development of the greenhouse, glasshouse, and glazed windows for private residences during the next eight centuries. The enormous expense of manufacture made glass cost-prohibitive for most people, so glazed windows remained a luxury for the abodes of royalty, the homes of the landed gentry and wealthy merchants, and ecclesiastical buildings. Through most of history, the homes of the lower ranks were designed with small windows that either had little or no glass, relying on shutters that could be closed in inclement weather.
Glass Manufacture
In Europe in the early 1800s, there was a great demand for window glass, which was then called "crown glass." It was made by blowing a bubble of glass and spinning it until it was flat. This left a sheet of glass with a bump or "crown" in the center. The bump was removed, and the rest was cut into flat panes. A highly skilled craft, manufacturing crown glass required ten specialist glassmakers. By 1825 the "cylinder" process had replaced the crown method. In this technique, the molten glass was blown into the shape of a cylinder. After the cylinder cooled, it was sliced down one side. When reheated, the cylinder opened up to form a large sheet of thin clear window glass. Thanks to this process, larger, higher quality glazed windows were introduced—which were slapped with an incredibly steep tax based on the size of the window aperture. Consequently, in the homes of the majority of the population, windows remained small or were absent altogether. It wasn't until after 1890 that machinery was developed for precise, continuous manufacture of sheet glass and the glass tax was lifted in Europe, assuring glazed windows for everyone.
People and Plants
What, exactly, were the Romans growing in their lapis specularis-covered structures in addition to cucumbers? Historians don't know precisely which plants were cultivated, but they do concur that in all likelihood, they were destined for the dining table. Members of the well-heeled aristocracy of the Roman Empire were apparently very partial to tasty, out-of-season, and possibly aphrodisiacal vegetable tidbits. However, the Romans did force flowers for sheer pleasure, as this remark from Seneca indicates: "[Is it not] contrary to nature to require a rose in winter and to use hot water to force from winter the later blooms of spring?"
During the Crusades (1096-1291) a wide variety of hardy herbaceous and woody plants—including roses, tulips, and peonies—were brought back from the Middle East to be cultivated outdoors in European church gardens and royal landscapes. The landscape was devoid of greenhouses, and plants weren't cultivated indoors; the Age of Exploration was several centuries in the future.
Organized collections of plants destined for the viridarium (a heated wooden shed for overwintering plants) first appeared in the 14th century, most notably in Salerno and Venice. In the 16th century, they evolved into botanical gardens throughout Europe with the founding of the universities at Padua (1533), Pisa (1544), Bologna (1568), Leipzig (1580), Leyden (1587), and Paris (1597). It was not until the Renaissance that there was a methodical approach to the study of nature, and, in particular, the growth of plants.
Importing Plants
Newly discovered flora arrived by the shipload in European glasshouses from all over the world, thanks, of course, to the vast fleets of trading vessels and the ever-elongating reach of commerce. European gardeners of the 17th through 19th centuries saw the arrival of orchids from the Philippines, palms from Madagascar, camellias from China, aroids from South America, sansevierias from South Africa, aspidistras from Japan, and cacti from North America. In the latter part of the 17th century, the first pineapple (also indigenous to South America) was grown to fruition in the greenhouses of Hampton Court Palace in London. By 1739, the brazier-heated greenhouses and glasshouses of the aristocracy were brimming with tropical plants, but ordinary people were still not growing plants in their homes.
It took another 120 years for the notion of growing tropical plants within the home to be legitimized as an engaging hobby, making the phenomenon a surprisingly recent occurrence. By the 1870s the technology of indoor horticulture was evolving at breakneck speed, as people developed a frenzied interest in anything tropical. Indoor gardeners on both sides of the Atlantic witnessed the arrival of creatively designed horticultural home furnishings in vast quantities and myriad styles. Rolling planters, plant cabinets, indoor arches and trellises, Wardian cases, ornate pot brackets, attractive arborettes (designed specifically for ferns), and plantable ceiling chandeliers abounded in the front parlors of any family with "discriminating taste." The trend-setting paraphernalia of the time enabled horticulturists to landscape their interiors—assuming there was sufficient ambient light. It is no surprise that those plants that tolerated low light levels became immensely popular. Aspidistras, palms, rubber trees, sansevierias, aroids, English ivy, and ferns became a must for any parlor garden.
As a side effect, the number of horticultural products geared towards indoor gardeners became staggering—for the time. Water-spraying squeegees and syringes, as well as insecticide sprayers and hand-held fumigators, made their appearance. And the manufacturers of horticultural products answered the needful clamor of the new indoor gardening public by introducing the mail-order garden catalog.
People have remained fascinated with indoor gardening, and many of us are familiar with a succession of interesting fads: the "bromeliad tree" of the 1920s and '30s, the terrarium craze of the 1960s, and the macrame plant hangers of the 1970s. The houseplant hobby lagged for a decade or so but experienced a renaissance in the 1980s. And it shows no signs of slowing down as an ever-increasing number of people desire to bring the outdoors inside in new and innovative ways.
Scott D. Appell is director of education for the Horticultural Society of New York and a member of the Publications Committee of the Pennsylvania Horticultural Society. He is a contributing author to Smith & Hawken's Book of Outdoor Gardening and Rodale Press' 1001 Ingenious Gardening Ideas as well as a botanical consultant for Gardens by the Sea: Creating a Tropical Paradise, published by the Garden Club of Palm Beach. In addition, he has written three books, Pansies, Tulips, and Lilies, all published by Friedman/Fairfax Publishers, Inc, New York. His private consultation company is called The Green Man.