If you have lots of space in your garden (acres), you could grow a collection of full-size deciduous or evergreen trees. We might explore the value of big trees in a future column, but we focus now on the space for trees and shrubs that are suitable for the space of typical residential gardens.
When gardening within limited space, gardeners often select dwarf fruit trees or smaller shrubs. These options could work well in the landscape, assuming the available space is large enough to accommodate the plant’s mature size and access for cultivating and (with fruit trees) harvesting.
The garden could include narrower spaces in which dwarf trees and larger shrubs would not fit well. Examples include side yards, a shallow bed before a wall or fence, or a narrow bed along a driveway or walkway.
The solution for such spaces is the espalier, which involves pruning and training a tree or shrub to control its form, and tying it to a wall, fence, or trellis to conform to a limited space.
Espaliers can be formal or informal in structure. The most popular formal structure is the cordon, which consists of a vertical leader and (usually) three tiers of horizontal branches. Several more elaborate forms have been developed over time, offering interesting configurations and greater pruning workloads.
Informal structures, typically based on a trellis, tend to have more natural appearance while being kept within the confines of a narrow space.
The ancient Romans initiated this method, and Europeans refined it into an art form during the Middle Ages. Espaliers are still popular today because in addition to their value as artistic features in the garden they can be positioned for ideal exposure to sunlight and reflected heat from a wall. Another benefit of espaliers derives from training branches to horizontal positions, which increases the production of flowers and fruits.
Espaliers might be called two-dimensional but they definitely have height, width and depth, The depth (the third dimension) is controlled to ensure that the plant fits into a narrow space.
The French term “espalier” originally referred to the structure (“shoulder”) on which the plant rested, and now refers to the plant itself, and also serves as a verb to describe the practice.
Espaliers can be more or less successful, depending on several variables. The most important variable is the gardener’s diligence in pruning and training the plant when it is young and throughout its annual growing season. Persistent snipping can produce a genuinely attractive and exceptionally productive plant.
Another important variable is the plant itself. Some trees and shrubs are well-suited as espaliers because their blanches naturally grow in horizontal forms, and respond well to pruning. Plants that grow vigorously can exceed even conscientious pruning and assume a shape of their own.
Even with well-chosen plants and regular care, espaliers are natural products that develop individual character and unique beauty.
My garden includes several espaliers, some of which are described briefly in the following paragraphs and accompanying photos. These are not exemplary espaliers, just case studies of practical gardening experiences.
Mission Fig. My column of last week included a photo of this tree. It has been growing close to a picket fence for over 40 years, and I have been working to limit its height to make the figs reachable and limit its depth to avoid intruding on the adjacent garden beds. I installed four-inch diameter posts on either side about 10 feet from the trunk and pruned away branches that increase the tree’s depth. A mature fig tree grows vigorously and responds to heavy pruning with rapid and strong growth. This project requires more monthly attention than I could provide.
The horizontal branches of this espaliered Gala apple tree produced a good crop in mid-July. (Tom Karwin)
Apple Trees. I planted two young apple trees that a nursery had pruned as espaliers. One is a Gala apple and the other has six different popular apple varieties grafted onto its branches. The Gala is planted against the garage wall, above a four feet deep planting bed. It has been growing well, but apple harvests require some agility to avoid trampling the plants in front of the tree. The multi-variety espalier is planted against a house wall, in an 18 inches deep bed. That tree’s fruit is easy to harvest (although the identifying tags are lost). These two trees demonstrate the value of proper placement.
Vigorous Rosa mulligani blooms in June. (A garden mirror is shown in the lower right.) (Tom Karwin)
Rose mulligani. This extraordinary rambling rose grows vigorously with canes that can reach 20 feet in length. I planted it against a redwood fence and installed three tiers of plastic-coated wire, held away from the fence on long-necked eyebolts. The rose is growing in a bed about two feet deep, so it is not difficult to access the plant to prune away canes that grow out from the plane of the fence, tie cooperative canes to the wires, and deadhead spent blossoms. This plant demands espalier treatment. Imagine what it would do if left to grow on its own!
Two Climbing Roses. These selections are Graham Thomas’ and ‘Polka, both capable of reaching 10 feet or more in height. They are planted against the house in three-foot deep beds, growing on hand-made copper trellises about six feet tall, so their height needs control. They are prominently placed and effectively located for periodical pruning of branches that grow out from the intended plane. Their location lacks sufficient width for horizontal branching, so blossom productivity is limited.
The Chilean Jasmine keeps climbing above twenty feet on this narrow copper trellis. (Tom Karwin)
Chilean Jasmine (Mandevilla laxa). This is a vigorous vine growing in an 18 inches deep bed on a six-inch wide hand-made copper trellis that rises about 20 feet on a post that supports a small deck. Its tendrils tend to grasp the adjacent apple tree, so they need control. Otherwise, this is a well-behaved plant that blooms regularly from late spring through the summer.
Lavender African Star Flower (Grewia occidentalis). This is a new project for a three-foot-deep bed in front of an eight-foot-high wall. The selection, found at the UCSC Arboretum & Botanic Garden, is an uncommon, not-too-large tree with attractive blossoms. It is well-suited for this microclimate, which has limited early sun and afternoon shade. This tree’s natural growth structure tends to be erratic so the discipline of espalier pruning will encourage it to grow into the intended form.
The Lavender African Star Flower’s blossom, shown in Barcelona. (Photo by Consultaplantas via Wikimedia Commons.)
Lessons learned: the success of an espalier could depend on plant selection, location, and (most important) regular pruning, ideally on a monthly basis.
If you have a narrow location that has full sun exposure and that an espalier could enhance, now is a good time of the year to begin such a project. See below for references to helpful websites.
This Lavender African Star Flower, the garden’s newest espalier, has been pruned to encourage horizontal branching. (Tom Karwin)
Advance your gardening knowledge
A good introduction to espaliers is Peter Thevenot’s article, “Everything You Need to Know About Espalier.” This is available on Fine Gardening magazine’s website, www.finegardening.com/project-guides/pruning/espalier.
Fruit trees are popular subjects for espaliers. The Grow Organic website presents a good video overview of issues related to fruit tree selection. Browse to https://www.groworganic.com/collections/bareroot-trees.
Wikipedia, one of my “go-to” sources of information on plants and gardening, has a helpful page on espaliers. Browse to https://en.wikipedia.org/wiki/Espalier and scroll down to Species Choices for lists of trees, shrubs, and woody vines that are well-suited for espaliers.
Fine Gardening magazine has announced a fee-based virtual course, “Sustainability in the Garden.” Here’s their description: “Join us as we take a deep dive into the complex and sometimes controversial gardening topic of sustainability. This on-demand lecture series features four separate classes related to the overall theme. Each highly engaging session is modeled after a college course and is taught by a leading expert in the field. With each class you’ll receive not only in-depth instruction but also informative handouts to help you understand and visualize the concepts being discussed. Each class is offered on-demand, so you can view it at your leisure.” The course instructors are well-qualified gardening specialists. To learn more and register, browse to https://tinyurl.com/b62zb542.
Enjoy your garden! The Cactus and Succulent Society of America’s recent webinar, “Out Of This World Succulent-Scape at the Orange Coast College Planetarium,” was quite interesting. Horticulture educator Joe Stead described the process of developing a large succulent garden at the college, and then relocating the garden to another site on the college campus. The garden design was impressive, and the large-scale garden development work was amazing. This institutional project demonstrated designs and installation methods that could be applicable in more typical residential gardening projects. The recorded webinar can be viewed at www.facebook.com/CactusAndSucculentSocietyOfAmerica/.
The Cactus and Succulent Society of America has posted several of its webinars online Browse to Youtube.com and search for “Cactus and Succulent Society of America” for a long and wide range of cactus and succulents topics from the CSSA and other sources. Some presentations are less than five minutes long while others are up to an hour in duration. Some are very competently done, and others are rather casual, but still include solid information.
Enjoy your garden!
Tom Karwin is a past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society, a past president and Lifetime Member of the Monterey Bay Area Cactus & Succulent Society, and a Lifetime UC Master Gardener (Certified 1999–2009). He is now a board member of the Santa Cruz Hostel Society, and active with the Pacific Horticultural Society. To view daily photos from his garden, https://www.facebook.com/ongardeningcom-566511763375123/. For garden coaching info and an archive of previous On Gardening columns, visit http://ongardening.com.