How do we learn what parts of a garden are more important than other parts?
Works of art have a natural and constituent hierarchy.
“In every work”, wrote Samuel Johnson, “one part must be for the sake of others; a palace must have passages, a poem must have transitions”.
These passages and transitions aren’t less important. They are simply different. They are sometimes invisible, though, because the observer is blinded by the wittier parts, like the ‘sun standing at noon’.
It’s hugely useful to understand these differences because they help the designer make cost and maintenance-commitment decisions. Here’s a helpful thought experiment: imagine moving through your garden as it is now, or as you imagine it. Let your eyes linger as they will, without forethought or pretense. Every movement engenders anticipation because you want to know what is around the corner. There is a sort of suspense, only sated as you discover natural or contrived ‘focal points’ where your eyes fall naturally on one spot, and then another, sequentially and predictably.
It’s a playful and simple game that loosens the imagination, revealing perspective and scale. There is nothing secret or profound about it.
Johnson wants us to focus on the passages, the supporting garden zones between the focal points. It’s counterintuitive, isn’t it?
Let’s look at some useful plants that bring structure and support to your garden design, plants you use to create support for key, focal plantings.
How do we chose these structural plants? We don’t want Hibiscus, or Ginger, Psittacorum, Plumbago, Bougainvillea, or any of the Pretty Boys that prance before our eyes demanding attention. What is wanted here is the strong, silent type.
Like all worker bees, our structural plants must be vigorous and reliable. They must dependably form a monoculture and need little-to-no mulch when mature.
And think about maintenance burdens, too. We allow high maintenance plants only where highly exposed, not in the support passages. This only makes sense: why spend money constantly pruning shrubs that you rarely see?
Not at all! Here are nine examples, from the largest to the smallest:
Clusia (Clusia guttifera) is a large shrub with thick leaves and, in many situations, preferred over Ficus or Viburnum as a dependable hedge. The indestructible Clusia, at eight feet tall and four feet wide or more, has a fabulous texture and does well with partial shade.
Saw Palmetto (Serenoa repens), of course, can reach eight feet or more for the silver variety, and slightly less for the more common green version. Slow growing, they are practically indestructible, and should be planted five feet apart or so.
Ficus Green Island (Ficus macrocarpa 'Green Island') is easily the king of small structural shrubs. Maintained at 24” or so, this medium-textured plant will form a dependable monoculture when planted thirty inches apart in full sun to part shade.
The Boston Ferns (Nephrolepis spp.) are actually a group of related plants in a variety of sizes, all with similar horticulture and all forming solid, maintenance free beds. Use them anywhere except the deepest shade or the fullest summer sun. Plant them about eighteen inches apart, but space the three foot tall Macho fern a bit wider. Control them by turning the weed-eater parallel to the ground and gently pushing the perimeter back.
Wart Fern, too (Polypodium scolopendria) will fill available space with an interesting texture about eighteen inches high and in the same conditions as the Boston Ferns. With time, a mature bed of Wart Fern or Boston Fern will scoff at all but the driest droughts, requiring only occasional supplemental water;