March / 2000
The Trellis Trend

by: Nancy S. Grant

  Remember the trellises of your grandparents' day? A plain white fan by the front porch with a rose rambling along it? A flat latticework grid leaning up against a wall with ivy or clematis weaving up to the top? Today, Kentucky gardeners are experimenting with new shapes, new materials, and a variety of plants to create trellises that are delightfully eye-catching.

Garden centers, hardware stores, and home improvement warehouses throughout the Bluegrass State have expanded their traditional offerings of redwood and cedar trellises to include pressure-treated lumber, vinyl-clad metal, wrought iron, and even sturdy PVC plastic trellises in a variety of shapes and sizes. And backyard do-it-yourselfers are experimenting with bending wood (fresh willow branches form easily) to create appealing designs such as hearts, leaves, and arched tops. Why the sudden revival of trellises in Kentucky gardens?

  Trellises offer a relatively inexpensive way to add a new design element to any size garden. Louis Hillenmeyer, Lexington native and owner of three garden centers there, notes, "A trellis can create a softening effect on a wall. I compare it to hanging a picture on a wall indoors: outdoors, if you have blank space between two windows a trellis can add interest. If you have a narrow space that's not quite big enough for a tree or shrub, a trellis might be just right."

  Not all trellises are anchored to a wall or porch. A freestanding trellis can function as a screen to hide work areas, as a fence to divide one section of a garden from another, or to mark property lines. An attractively shaped trellis can also stand alone as a focal point, similar to the effect created by a statue or birdbath. 
A trellis can provide instant shade, something many homeowners with few trees in yards with southern exposure really appreciate. The north side of a trellis in such a situation can become a microclimate, with the dappled shade and slightly cooler temperatures that are just right to encourage certain plants to thrive at its base. It's also a perfect spot for a bench or lawn chair for relaxing. 

  Rick Durham, Lincoln County native and home horticulturalist specialist with the county Extension service at UK, notes another advantage: "With a trellis, you're extending your growing space upward. A trellis adds height for plants and that's a good option for many small-space gardeners." 

  Indeed, fruit and vegetable gardeners are discovering that ornamental trellises make fine supports for blackberries, raspberries, pole beans, and tomatoes. Durham says, "The best tomatoes for trellises are the indeterminate type, that is, a tomato plant that keeps growing all season and can be pruned. The grape tomatoes work especially well and look terrific."

  Durham also recommends vining (not bush-type) cucumbers and garden peas for trellis culture. Gourd vines enjoy a ramble up a trellis, too, and provide a surprising accent in the garden.
Flower choices aren't limited to old-fashioned roses or clematis, either. "Just about any plant that you can train will work well on a trellis," Hillenmeyer says, "if you're willing to put in a little time and effort. 

  Hardy pea vines are quite vigorous growers with lots of flowers, and Gold Flame honeysuckle vine also looks good. There are some new climbing hydrangeas on the market, too." Hillenmeyer also likes two plants native to Kentucky-trumpet vines, which attract hummingbirds, and Dutchman's-pipe, a flowering vine that's important in the life cycle of several native butterflies. 

  Many other fast-growing vines make good companions for trellises. Morning glories and sweet peas, traditionally grown on fences, can literally reach new heights on trellises. Durham notes that some non-native perennial plants from warmer climates can also be grown successfully on Kentucky trellises, if they're treated as annuals. Mandevilla, sometimes called Chinese jasmine, grows readily from seed and produces fragrant pink or white flowers. There's even a native passionflower vine (passiflora incarnata) that survives Kentucky winters by dying back to the root, then sending up fresh shoots in the spring. 

  Kentucky's weather extremes do require a little extra planning on the part of trellis gardeners. When attaching a trellis to an existing wall, Kentucky gardeners have found that it pays to leave at least 3 inches of space between the trellis grid work and the wall. Not only does this give the plant room to grow, it also promotes good air circulation during humid summers. 

  Freestanding trellises must be firmly anchored to the ground to withstand Kentucky's gusty winds in any season. Whether installing a commercially made trellis or a do-it-yourself creation, Kentucky gardeners need to use 18-inch stakes belowground to provide a firm attachment for the trellis' uprights.
As with any garden project, it's important to match the size and shape of the structure to the growth habits of the new plant.


Trellis Types
Whether wood or wire or plastic suits your gardening scheme, you'll want to think about the size and shape of your garden structure first. Here are your choices:

Trellis
  A flat framework attached to a wall, or a freestanding flat structure that offers support for a plant; may consist of a simple rectangular grid pattern, curving lines, or some combination.

Arbor
  Provides an over-the-head growing space with an open, shady area underneath, rather like an inverted "U"; top may be arched or flat.

Pergola
  An arbor big enough to walk through, rather like a tunnel; often used dramatically to accent the view at the other end.

Espalier
  Not really a structure, but the effect of training a plant on a structure so the plant takes a certain shape; a plant growing up against a trellis, arbor, or pergola may be tied and pruned to form a certain design; wires and strings may be attached to a wall or fence to provide something for the plant to be tied to.-Nancy S. Grant


Trellis Tips
  Consider the effect of the weather on your building materials. Use galvanized nails or waterproof nylon cord to hold trellis pieces together. Avoid materials that will rust or rot.

Plan ahead for maintenance. If you're attaching a trellis to an existing wall or porch, use hooks and eyes and a furring strip instead of screws. If you change your mind or need to paint, you can move the trellis with ease.

  Choose a style you'll be comfortable maintaining. Do you have the time to clip, trim, tie, and otherwise train a plant into a formal shape? Would you prefer a wilder, more natural look that takes little effort?

  Match plant size to the structure. A mature wisteria vine is extremely heavy and needs a very sturdy trellis to grow on. Get to know the growth habits of the plants you're considering before you install your trellis.

  Be willing to experiment. Vines are a natural for trellises, but plenty of other plants will appreciate some support. Zinnias and sunflowers can be attractive poking up through a latticework-and they won't be flattened in the next windstorm. Try new combinations-you might make a beautiful new discovery!

Energy journalist NANCY GRANT is a member of the Cooperative Communicators Association and the American Society of Journalists and Authors.