Gardeners who accept the changing nature of plants have the most interesting and successful gardens.
Some plants can thrive—or just hang on—for many years. Plants with the shortest life spans are those we call annuals, which sprout, bloom, drop seeds, and fade away in a single season. Actually, these plants continue through multiple generations by going through seed phases each year. This life cycle differs from that of perennial plants, but it’s easy to perceive life continuing for these plants through their regular periods of “seed dormancy.”
Given favorable conditions of soil nutrients, moisture coupled with the desired degree of moisture retention, and the desired degree of exposure to sunlight, most plants will continue for many years.
We must acknowledge the importance of occasional attacks by insects or diseases, but healthy plants are generally capable of surviving such hazards.
The growing environment is most important. Some plants have evolved to thrive under specific conditions. We generally think of plants that grow best in good garden loam, with moderate moisture and six or more hours of sunlight each day, but there are many exceptions to this standard.
Some plants grow well in soil with greater proportions of clay or sand, or with minimal nutrients.
Then there are epiphytes: plants that grow upon another plant or object merely for physical support and live on airborne moisture and nutrients. Kinds of epiphytic plants include lithophytes, which grow on bare rock or stone; chasmophytes, which grow in the crevices of rocks, and cremnophytes, which can grow on cliff faces.
Some “aquatic” plants grow immersed in water. I have recently added an Erebus Canna (Canna glauca x generalis hybrid and an Anytus Japanese Iris (Iris ensata ‘Anytus’) to my pond. Conversely, “xeric” plants manage with very little water. Such plants include succulents, notably, e.g., cacti, aloes, agaves. There are many gradations within this wet/dry range.
Then, we have sun-loving plants and those that prefer very little sunlight and could even burn when placed in full sun. Again, plants have preferences for various levels of exposure.
Other habitat preferences of plants relate to wind intensity, site altitude, air salinity, etc.
All this variation raises the importance of the gardener’s research into a plant’s native environment. Plants have evolved for several generations to flourish under particular circumstances, so the gardener should select plants that could grow well under his/her specific garden conditions, or take reasonable steps to provide the plant’s preferred conditions. Fortunately, many plants can adapt to conditions that are not quite what may be best for them, but they will generally grow best in a spot that resembles their native habitat.
The gardener represents the greatest threat to a cultivated plant’s survival.
The dangers begin with the installation of a plant in a spot that lacks the conditions that the plant requires. This is “right plant, wrong place” problem. The eventual result is a plant that should be moved to a more compatible spot and perhaps replaced with a plant that would be better suited for that location.
At another level, we have plants that have outgrown their original location, so that they are crowding nearby plants, obstructing a garden walkway, or simply being out of scale for the landscape.
Whenever a plant has suffered under incompatible growing conditions or has grown beyond the intended or desired size, the gardener should recognize the problem and correct the situation decisively. A garden visitor might provide an independent yet diplomatic assessment of a particular plant’s misplacement. The gardener should avoid the view that plants are permanent assets or irreplaceable sentimental attachment, and instead accept the occasional need to transplant or recycle a plant, and welcome the concurrent opportunity to introduce a new botanical treasure into the garden.