A landscape should be viewed as a work in progress. Its main components are living organisms which grow, spread and change as they mature at different rates and in different ways. What we start off with is not what we end up with, sometimes in ways we did not anticipate. And that is part of the fun and wonder.
Planting for diversity is a common theme in arboriculture and urban forestry. The premise is to preclude a major disease or insect infestation wiping out a majority of the urban (or natural) forest as has happened in the past and is ongoing in the present. Diseases such as Chestnut Blight, wiping out American chestnut trees, Dutch Elm Disease decimating American elms, Oak wilt killing trees in the oak species. Insect infestations are taking their toll as well. Emerald Ash Borer kills native and non-native ash trees and the Mountain and Western Pine Beetles have decimated pines across western North America. Most of this devastation is evident in the monoculture approach to planting and proves over and over the wisdom of having an urban forest comprised of a diversity of tree species.
When it comes to the individual landscape, diversity is equally as important, perhaps for more reasons than just surviving a cataclysmic event. It should include not just a diversity of trees, but a variety of plants from herbaceous and woody shrubs, annual and perennial flowers as well as grass species. Besides creating an aesthetically pleasing appearance, these all contribute to a healthy, living eco-system that becomes self-sustaining in a way many don’t appreciate.
When considering diversity, you should consider not only species, but longevity, structure, size, characteristics such as blooming (or not), deciduous and evergreen. Why? Because not only does this give you a larger plant palette from which to choose, it also provides a more interesting design, will draw in an abundant variety of beneficial insects and will also contribute to diversity within the soil which means a healthier environment for the plants. This living eco-system you are developing does not stop at ground level but goes deeply beneath the surface.
Does your design matter? Only to the extent it meets your goals and desires. There are many designs and styles: Formal or informal; themes such as Italian, Oriental, English Country Garden, French. A design may meet your aesthetic goal but also serve a specific purpose: kitchen garden, xeriscape, encouraging pollinators and butterflies, or focusing on species from a specific area. It may be a combination of several. It doesn’t matter if it doesn’t fit into a specific designation or into many. What matters is that it suits you.
The wonderful thing, or I should say one of the many wonderful things about a landscape: it is never finished. It transforms itself daily if you pay attention, but even a casual observation will take note of the changing seasons with the perspective each gives. Then one day you realize you now have to look up to see the buds at the top of the little sapling you planted instead of bending down to note its growth. Perhaps that sapling is even now towering over your house.
Because you didn’t just plant trees, you planted understory shrubs and flowers, both perennial and annual as well, birds come in droves. Many of the annuals reseed themselves and so you have an ever-expanding flower garden that brings in pollinators and hummingbirds. Your landscape is now, literally, a-buzz.
Working in a garden becomes a time to share with a tremendous number of other living organisms as they go about their daily tasks. There is never a dull moment, many peaceful ones, but never dull. It is a time to let go of problems of the moment, let your mind wander. It gives you a task to focus on, gets you out-of-doors on your own terms, gives you physical exercise and mental stimulation. And at the end of the day, there is a self-satisfying feeling of accomplishment, the results of which you watch grow day-to-day.