|Standard Cyclopedia of Horticulture|
Pergola. The word "pergola" closely interprets its original meaning: from the Latin "pergula," a projecting roof, shed, or vine arbor, from "pergere," to reach forward or project; and from the Italian "pergola," a grape which remains upon its trellis all winter. From this derivation and use of the word, it will readily be seen how the term has become one of common usage in modern garden design, rightly or wrongly to designate almost any type of arbor or vine- support in the present-day garden. In order to understand the purer and less general meaning of the word, the garden vine-supports may be divided into two kinds or types: (1) treillages, decorative or otherwise, which may broadly be considered as designed in one simple geometric plane, perpendicular to the garden, their dimensions, height, and length being determined only by their use and detail design; and (2) pergolas ana arbors, designed or planned in three planes, having height, length, and breadth, and, in brief, being architecturally conceived tunnels over which vines are trained or grown, the arbor and the pergola differing only in the detail of their design.
The pergola is invariably flat-topped, its semi-open roof being formed either by rustic poles or timbers of varying size, laid at right angles to the length of the structure, or by similarly laid but regularly spaced rafters or timbers of definite size and cut, this partially open roof being supported in either case by posts or columns of an architectural character equally and oppositely spaced. In simpler description, the pergola is a horizontal vine-support raised upon piers or columns, each of the latter standing free and independent of the other, the vines being encouraged to lie flat over its top.
The arbor, in distinction from the pergola, is, in its simplest form, a treillage or vine-support of a skeletonized form, with sides and top generally alike, its top, or roof, being flat or curved as its design may determine. In detail, its construction consists usually of regularly and oppositely spaced wooden posts supporting not over-thick strips and rails of the same material, these extending horizontally. Other material than wood is often used in arbor-construction, but the design and character remain generally the same,—a skeletonized tunnel for the support and training of vines over its entire surface. Therefore, while similar in origin and use in the garden, the pergola and the arbor must not be confused in their character and design. The arbor is, in fact, a development of the even earlier-used pergola, which in medieval gardening often became the pleached alley (or allee), and in the early French and English gardens the very decorative and often complicated tunnel or gallery of treillage.
The pergola is numbered among the oldest pieces of garden architecture extant. The Egyptian used it as a covered walk from one part of his domicile to another, or to his garden house; Pompeii and ancient Rome prove its constant use, Vitruvius, describing the garden attached to the villa of Diomedes, saying, behind the fish pond ornamented by a fountain, there was a platform over which vines were trained on a wooden framework supported upon six columns of stucco. In Italy, the pergola can be traced through the various transitions of the Italian gardens from those of early imperial times through the medieval, to the architectural or formal gardens of the Renaissance and today. In the great medieval period, the pergola and the cloister were often synonomous in use, differing only in the material of their construction, the latter being largely the outgrowth and development of the former. As early as the beginning of the fifteenth century, the pergola was in common use in France, being found not only in the magnificent gardens of the kings, but as a feature of the smallest town gardens of Paris. Riat, in his most authentic garden history,
"L'Art des Jardins," carefully notes and describes the use of the pergola at this time; Hill, one of the earliest of English writers on gardening, in his "Gardener's Labyrinth," published about the middle of the sixteenth century, claims the pergola to be "so winded that the branches of the vine, melon, or cucumber, running or spreading all over, might shadow and keep both the heat and the sun from the sitter there under, and offer him cool and shaded passage." William Horman, in his "Vulgaria," published in 1519, tells us that alleys in gardens, covered with vines, do great pleasure with the shadow in parchynge heat, and clusters of grapis maketh a pleasant walkynge alley." Thus, in brief, it will be seen that the pergola and its close kin, the arbor, have been used in all time and manner of gardening, the earlier English colonists bringing both to America, where their popularity, especially of late, has been so great as often to cause their degeneration in design and misconception in use. There is no decorative or useful feature in the garden scheme which has been more inadvisedly used than the pergola. Like our gardening, which has naturally become composite and therefore often impure in taste, so the pergola has become subjected to all manner of diversity in use, material, and design. It can be made an excellent motif and component of a good garden scheme, if properly and carefully considered!. Its value is not as a mere floating incident, untied and non- related to some stronger element or to the frame of the garden. It must be given a "tying-together" or corridor value in order best to serve and express its use. The garden should be designed in a manner to call for its use as a covered passage between the house and the garden entrance; or to connect one garden, or part of a garden, with another; or to separate garden from garden, offering substitute for the wall, hedges, or lattice, which might otherwise be used; or allowed to enframe or terminate the garden, a situation in which it may often be used to fine advantage either alone or in combination with a garden house or shelter; but it should not be so designed and placed as to serve merely as an isolated decorative garden feature. For such location and use there is the garden shelter, the tea-house, the pavilion, the seat, and various exedra, far more suitable. As is generally the case with all decorative garden motifs, the design and material of the pergola should be in strict harmony with its more important and controlling architectural surroundings. This does not mean, nor does it necessarily follow, that the material of the pergola should be like that of the house, garden wall, or other more or less important adjacent architectural features; but it does mean that its architectural character or style, design, and scale, must be determined and dominated by that common to the entire problem, and its material be in harmony or at least reflective. The designer or builder is safest when he considers not only his pergola but all of the architectural features of the garden as details, the character of which are to be largely determined by, or closely interrelated with; the architectural treatment of the garden and its environment as a whole. Materials and minor methods of expression may vary with personal taste, but architectural period and style cannot, for with a lack of appreciation of the proper architectural relation between the interrelated parts of a garden comes a breaking down of one of the most important principles of garden or other composition, namely unity of idea.
While, of course, there can be no rules governing the dimensions of pergolas, the relation of width to height is most important, as is the relation of height to length. The scale may be either human or relative. The width of a pergola or arbor, however, is seemingly best when slightly greater than its height, for if less it will appear stilted and in poor proportion. From diagrams A to E in Fig. 2869, it will readily be seen that (A), showing a proportion of 4 to 3 is less pleasing than (B), 4 to 4, or even (C), 4 to 5. When the width increases noticeably over the height, as in (D) 4 to 6, or (E) 4 to 7. there is a resultant weakening in proportion. As for length, this of course is determined by the individual problem, but in no case should the length be merely equal to, or less than, the width or height. In summary, the dimension of the pergola should produce a form of sufficiently dominant and pleasing horizontal and perpendicular dimensions to produce a satisfactory feeling of stability and repose.
In regard to plant materials used in connection with pergolas, the effect sought is that the pergola shall count as a support for vines; the variety and kind of growth, however, must naturally be determined by the exigencies of the particular case. Vines of fine and delicate foliage, flower, and fruit are better suited to the delicate arbor or treillage, and the larger-leaved, more heavily fruited vines to the architecturally stronger and coarser pergola. Also, vines with coarse and woody stems, such as the wistaria, the grape, the bittersweet and the like, are better adapted to the true use of the pergola, as a rack upon which vines lie, not a treillage or support up which they climb or against which they are trained. CH
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963