Savvy gardeners know that autumn provides optimal conditions for accomplishing a wide array of landscape tasks. These include bulb planting; transplanting of perennials and shrubs; installation of fruit, ornamental, and shade trees; fertilization and dormant seeding of lawns; tree fertilization and mulching; invasive species management; hardscape installation; and regrading of landforms to facilitate drainage or to address other issues.
All of these potential interventions arise from the one most salient aspect of the autumn landscape: it enables the fullest perspective from which to view the landscape for all of its assets and deficiencies. In the autumn garden, we can plainly see what worked and what did not; which plants may need more space; where we could have used some annuals or might plant some bulbs. Likewise, the details of the larger landscape – trees and woodlands – are also arrayed in stark relief and become more explicitly legible at this time of year. In short, autumn provides the greatest amount of information from which one may derive an accurate evaluation of our natural surroundings.
Before autumn falls to winter, I review all of my gardens from a variety of vantage points, and then note not only problems or issues that need to be addressed, but also the latent potential of the landscape that may be less obvious at other times of the year. Oftentimes, I know and note the solution immediately; it could be as basic as adding a few more individuals to enlarge an existing planting of one particular variety, or removing a variety that simply is not living up to my expectations.
For instance, several weeks ago, I decided that I am done with Siberian iris (Iris sibirica). While they may grow almost anywhere without complaint, they are finicky about flowering, sprawl sloppily around and over their neighbors, and require back-breaking removal, division, and replanting on an almost annual basis to maintain floral productivity and restrain their tendency to increase exponentially in size.
However, inherent in any problem is an opportunity. The removal of those now detested Siberians has opened an enormous space that can host new and exciting varieties. While I really enjoyed the irises’ grassy foliage, their stubbornness to flower suggested to me that I might as well just plant an swath of ornamental grass – in this case, the native little bluestem (Schizachyrium scoparium) – and still have room to add several individuals of the vegetatively restrained, yet quite floriferous Japanese iris (Iris ensata), as well as more ‘Goldsturm’ coneflowers (Rudbeckia fulgida var. Sullivantii ‘Goldsturm’). In addition, I will interplant bulbs amongst all but the coneflowers, which will spread to form a solid mass. Thus, in no time at all, a blob of flash-in-the-pan, uncooperative perennials can be transformed into a dynamic ensemble that provides multi-season interest. All it took was a short walk in the garden with paper, pen, and a critical eye.
The big picture
In reviewing my work, I do not focus on the details alone. No landscape is legible or rational if designed and executed without a holistic understanding of the dynamic interactions of all its constituent elements. The long, broad view of the panorama is the reality check by which I evaluate how faithful I have been to my vision, and indicates those elements that still remain at large, such as a spring-flowering specimen tree to punctuate the visual sweep of unforested part of my landscape. When my mind turns to that project in particular, I cannot avoid thinking about how wonderful it would be to have that element in place for the eventual reawakening of the landscape come spring.
Of course, the broad view of the landscape does not fade to soft focus at the boundaries of the cultivated site. Our wild surroundings not only form an important framing element for our built and cultivated environments, they also interact with these environments in ways both aesthetic and functional. If one of those halves is unsustainable, the whole has not a chance.
An appropriate example of such a discontinuity is the presence of invasive, exotic plants in the landscape. To those of us who are passionate about invasive species management, a beautiful garden surrounded by invasive species is similar in spirit to a Palladian villa set in the middle of a junkyard. Invasives impoverish the landscape in a multitude of ways.
Fortunately, the very nature of invasive plants allows us to easily identify, isolate, and eradicate them in autumn. Invasive plants owe much of their virulence to the fact that they break dormancy earlier than natives in the spring and defoliate later than natives in the autumn, thus achieving a photosynthetic edge over indigenous flora. If you see a shrub in the forest fully foliated or even green at this time of year, chances are that it is an invasive exotic. At the time of this writing, foliage of glossy buckthorn (Frangula alnus) has yet to even lose its green color, while burning bushes (Euonymus alatus) and barberries (Berberis thunbergii) glow in various shades of pink among the pale golds of Asiatic bittersweet (Celastrus orbiculatus) and Norway maple (Acer platanoides).
While one might assume that it is too late in the season to control invasives, most woody plants – trees, shrubs, and vines – remain susceptible to systemic herbicides during dormancy, particularly in autumn and late winter, and are often more easily accessible during those times. In sensitive locations, this is often the safest option, since treatment can be precisely targeted with minimal risk of adverse effects on non-target species.
A call to action; or, you snooze, you lose
Take advantage of what autumn allows us, and do so with all due haste, for winter will be upon us before we know what hit us. Planting and transplanting projects ought to be completed within the coming weeks, but trees and beds can be mulched essentially until there is snow on the ground. Likewise, grading and hardscape installation can occur until there is frost in the soil.
While the clock may be ticking away and our window for accomplishing fall tasks may be closing, it is never too late to evaluate our surroundings – built, cultivated, or wild – and begin planning for work to be done in the winter, as well as in the springtime that we will all await for the next five months.
By Terrence Trapp, Director of Horticulture
October 1st, 2011