Controlled Form In The Garden

I was off today although I did pop in briefly to pick something up. I saw Larry, Bill, Dr. Gredler and Vern. I heard that Marv and Marianne were in earlier as was Janice and the other carpenter Grumpies. In the course of sifting through my 2010 photos, I've been running across many woodies that have been sheared, snipped, guided, encouraged and otherwise controlled for various purposes. All woody plants have a natural form; rounded, upright, horizontal, etc. However, there are certain types of woodies that have been historically selected because they can be controlled and shaped in to forms with a specific intent in mind. For instance, the hedge above (Chicago Botanic Garden) is a yew (Taxus sp.) hedge that separates two garden areas. This close spacing of yews has allowed a very tight arrangement that has become a "living wall" that is functional and could serve as a backdrop for other plants beyond its primary intent of garden separation. In the three pictures below are some boxwoods (Buxus), also at the Chicago Botanic Garden, planted tightly and controlled to create these squares that also define open spaces that have seasonal plantings for color, seating areas or a formal setting respectively. Shaped forms like these require frequent attention and need to typically be sheared at least twice per year to keep a tight shape. Access can be tricky depending on adjacent plantings and other obstacles. We have many sheared hedges at RBG and they do require some TLC and time must be found to keep up with not only the shearing but debris collection (related to shearing) as well. Most of us have shears and/or hedge trimmers in the garage and bring them out on occasion when some of our foundation plantings get overgrown or need a light haircut. We all have the overzealous neighbor that is "really in to it" too. I have four large yews (Taxus) in front of my house that are about two years behind on trimming. Sheared forms can lend a sense of formality to a landscape or can become focal points because of their interesting shape and/or position in the landscape. Again, the implications of maintenance need to be considered. A good example is the formal allee' of lindens (Tilia) at the Chicago Botanic Garden (directly below) that always look good but have to be sheared not only on the sides but need to be leveled on top and below. I can't imagine the amount of work involved with this perpetual process but wow, what a statement! Look closer at the picture and see the repetition of concrete spheres along the pathway that helps define the ground plane and lead the eye through the space. I'll address repetition in a near future blog. If you are considering using woody plant material to create a hedge, do more research regarding appropriate spacing to make sure you will have a "full look" in a reasonable amount of time. Some woody plants are sparser down low and may require a closer spacing to make sure foliage is full all the way to the ground (if desired). As hedges grow, it's important to be wary of the fact that a hedge will start to shade itself out with age and it's not uncommon to see larger (taller) hedges that have become wider at the top as the lower foliage (more shaded) can't keep up with the same growth rate. It's recommended, in most cases, to encourage/maintain a slight slant on the sides of a hedge (leaving the hedge wider at the bottom). This allows the lower portions of the hedge more light early on in life. The other consideration is that when you are shearing (keep them sharp!) or running hedge trimmers over a plant, you don't have to shear every square inch of the plant! Meaning...only address the growth outside of your "window" of desired shape. Less vigorous areas that look like they don't need shearing, should be left to keep filling in their space even if they have new growth. Below is the hedge collection at the Morton Arboretum (Lisle, IL) which shows a wide range of hedges. That's Marv and Terry eyeballing the hedges. They do most of our hedge trimming but Big John, Larry, Bill and Little Jerry also keep busy too. Further below is a large burning bush (Euonymus alatus) hedge at the New York Botanic Garden (NYBG) and an "arching" yew (Taxus) hedge that is parallel to the grade at the Brooklyn Botanic Garden, and an impressive, sinuous yew hedge at the Central Park Conservatory Garden. Hedges can be tall or quite short as seen with the boxwoods defining the Martha Stewart Herb Garden at the NYBG (four pictures down).
Controlled form of woody plantings (not just evergreens and broadleaf evergreens) may also lend itself to a certain garden style or intended garden function. Below is a "bear" form at the Huntington Libary, Art Collections and Botanical Garden (Los Angeles). I'm not sure if that is boxwood but it sure lends itself to serious pruning. Growth rates will vary depending on the plant itself, climate and amount of nurturing. Japanese and Chinese gardens have very beautiful plant forms that have extreme human inputs for training and shaping. Further below are some boxwoods (Buxus) in the Japanese garden at the Chicago Botanic Garden and the Japanese garden at The Huntington. While this garden style is informal, the "hand of man", so to speak, is quite evident and vital in creating the forms that create such strong symbolism and effect in these gardens. Our Japanese garden is no exception in terms of diligent maintenance.
Other controlled forms mighty include espalier (directly below), bonsai, etc. Regardless of the intent in controlling the form of a woody plant, doing it well is vital to maximize the visual appeal and perhaps function of that specimen. Gardens can quickly become overgrown and shearing and downsizing plants is a common task that many of us become involved with annually. Know your plant first and create a maintenance plan that works. The bottom photo features the sheared azaleas (Rhododendron) at the Getty Museum in LA. Their challenge is not only the shearing but catching/collecting debris so it wont get in to the water feature! This involves plywood bridges over the gaps and a whole lot of work.