Trees in training

Topiaries and espaliers are shaping up to be good sellers

By Elizabeth Petersen

Both topiary, the art of pruning trees and shrubs into striking shapes, and espalier, the practice of containing trees on single, flat planes, claim distinguished histories. Both techniques developed as the result of European practicality — the restraints of walled gardens — or from European aristocratic aesthetics that required carefully controlled plantings centuries ago. In 21st century America, the need for dynamic plants in small spaces and a taste for more formal plantings are fueling a renewed popularity for the unique structural qualities of topiary and espalier.

The once unlimited, wide open spaces of the United States have increasingly changed into clusters of huge, formal houses on tight lots, where the room for plants is limited to a couple of urns flanking the entry. What plants look appropriate in these spots? The fanciful spirals, double spirals, poodle or pompon cuts and even more elaborate designs of topiary. And what about the large, blank wall with only a strip of soil beneath? Perfect for espaliered structures. With that in mind, Oregon businesses are growing and shiping neatly shaped and sheared topiary sculptures as well as trim, trained espalier trees to markets across the country and throughout Canada.

To topiary or not

Fairdale Nursery in Wilsonville, Ore., and its sibling business, Countryside Nursery, located just a few miles away in Aurora, produce two main types of topiary: pompon pines and shaped dwarf Alberta spruces. Peter Eastman, inside salesman for the nurseries, recently explained the processes and the products. Scotch pines (Pinus sylvestris) and some Austrian and Japanese black pines (P. nigra and P. thunbergii, respectively) are grown from seed in containers for three years, he said. Then these well-established liners are transplanted into the field, where they continue to grow unpruned for two to three more years, establishing their natural shapes and developing good size. At five or six years, the topiary shaping begins.

Trees are “severely pruned, stripped down to an attractive, balanced, sculptural form, with only tight buttons of growth left at the end of each branch,” Eastman said. After the initial shaping, the Scotch pines are left to flush out for another year before they are dug and sold. The Austrian and Japanese black pines take at least one year longer to develop their tight, “cloud-pruned pods,” Eastman said. Trees are cut back hard every spring, when newly sprouted candles are sheared off, and again in August, when any errant growth is clipped. As long as customers continue to cut back the candles, topiaries will stay sculpted, but left unsheared, they quickly lose their tight shapes and sprawl out into looser looks.

Fairdale and Countryside nurseries, a combined 250 acres on four farms, also produce topiary forms of dwarf Alberta spruce (Picea glauca var. albertiana ‘Conica’), a mainstay of the Oregon nursery industry. These trees “never see a field,” Eastman explained. All are grown entirely in containers, where they are hand-shaped. The process for creating single and double spirals consists of “spinning and shearing.” Each tree stands on a lazy-Susan-type rotating wheel, and a ribbon defines the spiral. Then workers use handheld shears to “spin and shear, spin and shear.” Finish trimming polishes the look and exposes the tree trunk.

Started in No. 1, 2, 3, 6 and 10 containers, the shaped trees are transplanted into the next larger pots, including No. 15 and No. 20 pots, and left to grow for two more years, when growth is full enough to be sold. “We originally offered topiaries only in 10-gallon and larger sizes,” Eastman said, “but we found that 3-foot-tall topiaries in 6-gallon pots are in high demand because they are an ideal size for growing in ornamental containers. Now, the 6-gallon topiary has become a very popular price point with customers.” Spiral and poodle-cut topiaries from these nurseries go to independent garden centers, rewholesalers and larger landscape companies from California to Maine, before finding their way to the gardens of consumers.

Monrovia takes topiary to new dimensions

Monrovia, poised to celebrate its 80th anniversary this year, also contributes to choices of topiary trees. In fact, Monrovia’s “trained topiary forms” set the stage at such entertainment destinations as EPCOT Center, Walt Disney World, Tokyo Disneyland and Disneyland. At the company’s California operation in Visalia, stylized junipers offer customers widely different looks, from the fast-growing, upright J. chinensis ‘Spartan’ that works well for spiral and poodle columns, to the slower-growing J. scopulorum ‘Medora,’ which forms narrow, bluish green columns for formal accents in smaller gardens.

The fountainlike, versatile J. chinensis Mint Julep, renowned for its brilliant mint-green foliage, grows wider than it does tall, making it a good choice for pompon shapes. ‘San Jose’ matures slowly into a wider-than-tall topiary sculpture with stiff, irregular branching, and J. procumbens ‘Nana’ (dwarf Japanese garden juniper) forms a dense mound of branches that can be shaped to look like the handles of a basket. The growers at Monrovia propagate and grow the plants, training them for as long as seven years before they are well-formed and ready for sale, explained product labeling manager Brian Jacob of Monrovia’s Dayton, Ore., site.

In Oregon, where Monrovia has fashioned plants for 20 years, the crop consists of a completely different line: topiary shapes are grown primarily from dwarf Alberta spruce. Conifers grown there, both trained and untrained, account for upwards of 40 percent of the nursery grounds. “The demand for dwarf Alberta spruce is incredible,” said Jacob, so Monrovia’s production stays pretty steady, hardly reacting to market fluctuations.

Trees at Monrovia are pruned in the containers in which they will be sold, in sizes from No. 1 to No. 25. They come in such shapes as spiral, double spiral, pompon or poodle cut and a recently introduced line of Italianate forms.

“Experienced topiary craftsmen select unpruned trees from among the rest of the crop, picking out plants that have the appropriate characteristics for pruning into particular shapes,” said Jacob. “Since shaping is done freehand, these artists develop a keen eye for this type of potential.

Trees in the new line are named for Italian cities and fashioned after plants discovered in Italy by the late Monrovia craftsman and plant hunter Cliff Comstock. These topiary sculptures combine shapes on a single plant, such as pompons with spirals, for a more unique look. “This new line has gone over pretty well,” Jacob said. At the Oregon operation, about 1.5 percent of production is in topiaries, and of those, about 7 percent are made in the new Italianate style.

Later this year, Monrovia will introduce a scaled-down choice in topiary trees, the new Tabletop Topiary Collection, which will offer four plant varieties (Laurus nobilis, Myrtus communis, Olea europaea and Rosmarinus officinalis) shaped into three special forms, each grown in a 7-inch terra cotta pot.

New-old European espalier techniques come to Oregon

Fruit tree and grape growers have been using espalier techniques to maintain plants on flat surfaces, be they walls or other structures, for a long time. In recent years, Cascadian Nurseries in Hillsboro, Ore., has taken espalier and pollarding — another size-control method in which new growth is cut back to the permanent structure every year — in a new direction.

Cascadian’s efforts offer new options for gardeners and landscapers: ornamental and flowering trees with branches meticulously trained to grow in horizontal tiers on bamboo trellises. The trees are marketed under the name Trees with European Artistry, a credit to the inspiration that struck owner Fred Meisner, who had emigrated to the U.S. from Holland in the 1960s. On a visit back to Europe, Meisner observed the strikingly elegant trees with symmetrical, tiered branches that are widely grown, and he thought they would be appreciated by discriminating Americans, too.

The new program started with experiments using the London Plane tree (Platanus x acerifolia), which proved highly adaptable to the shaping process. Cascadian Nurseries now offers a selection of beautifully tiered trees, that includes three varieties of linden (Tilia cordata ‘Greenspire’ and ‘Shamrock’ and T. americana ‘Redmond’) and four varieties of flowering pear (Pyrus ‘Edgewoodii’ and P. calleryana ‘Aristocrat,’ ‘Autumn Blaze’ and New Bradford). The elegant formality of these trees is popular not only for use in confined areas, but also on large estates, where they are used to line long driveways or to establish privacy screens, and in commercial landscapes where they stand out as unique statements.

Cascadian general manager Jim Larson explained the process. First, 1.5-inch caliper bare-root trees between 8 and 12 feet tall are planted in long rows, about 10 feet apart, in winter. Trees grow unencumbered for about a year, and then branches about 30 inches apart are chosen for the permanent structure and tied horizontally to bamboo trellises to start the training. All other branches are removed, and for five to seven more years, growth is cut back to the main structure once or twice a year. Finally, well-formed trees grown in a flat plane, all with horizontal branches the same height, are ready for sale.

Landscape contractors and architects may specify the use of a single tree or they may plan to line up several and use them to create a wall for effect or privacy. Either way, trees that might naturally grow 30 or 40 feet tall are kept at well-controlled 12- to 14-foot heights and as broad as the permanent structure allows.

The biggest issue for dealing with these specialty trees is transportation. With bamboo frames attached, trees are awkward and unwieldy, especially when mature. “We can only fit about 12 in a semi-truck,” Larson said, “and they have to go in diagonally, so they take up a lot of space. But, we stuff other plants around them to fill the trucks.”

If the demand continues, consumers may soon find even more trained trees to choose from. Experiments continue at Cascadian Nurseries to find new varieties of ornamental and flowering trees that respond well to espalier and pollarding. For instance, both katsura tree (Cercidiphyllum japonicum) and evergreen dwarf magnolia (Magnolia grandiflora ‘Little Gem’) are now growing in long, narrow rows there. Under careful supervision, they may be the next to carry on the ancient European tradition.

Elizabeth Petersen writes for gardeners and garden businesses; she coaches students and writers; and she chairs the Oregon Plant A Row for the Hungry project. Contact her at gardenwrite@comcast.net.

Digger magazine is produced by the Oregon Association of Nurseries Publications Department. publications@oan.org