Autumn will not officially arrive for several weeks but for most gardeners, the passing of Labor Day signals an end to the summer season. September is my favorite month for gardening. Mild summer-like days intermingle with crisp, comfortable evenings providing an ideal opportunity to undertake many landscaping activities. Warm, dry, workable soils and hopefully, more reliable moisture during the fall season, make the month of September the ideal time to prepare new gardens and renovate lawns.
A stroll through our gardens in late summer, however, can be a disappointing journey. With barely more than a half inch of rain in August at the time of this writing, many lawns are dry and crispy and even established perennials are wilting. Wandering wildflowers, monumental clumps of crabgrass, and weedy intruders seem to have appeared out of nowhere and many of our borders have become a monotone, lackluster green, with sprawling foliage and unsightly withered flower stalks.
Weeding gardens has become my top priority this week, especially the removal of seed-laden intruders like crabgrass, oxalis, spotted spurge, and copperleaf. Bittercress and chickweed, that dispersed thousands of seeds this spring, are beginning to sprout and are also primary targets. Tiny dandelion sprouts are easy to extricate now, when their taproots are just beginning to form. Look up these common weeds on-line if you are not sure what they are. Be sure to look beneath the drooping foliage of waning perennials where many unwanted intruders lurk, secretly scattering their seeds. A few minutes each day will save hours of weeding next spring.
I grow vast numbers of hostas and daylilies, many of which are starting to look worn and tattered, although a few late-bloomers have lovely blossoms including the showy yellow daylily “Sandra Elizabeth” and the sweetly scented, pure white blooms of hosta “Royal Standard.” Spent stems and brown foliage can often be gently eased from among the new leaves of daylilies by using fingers like a rake. For hostas and other perennials, clipping the spent flower stalks and some of the flopping or declining foliage can dramatically improve the appearance of the garden.
As I wander from garden to garden, I pause regularly to critically analyze my lawn, gardens, and shrubbery. My notebook and camera are always nearby to note perennials that require division or trees and shrubs that need pruning or relocation. Digital images are snapped of my perennial borders to remind me of the mature size of my perennials at season’s end to avoid over-planting next spring when there appears to be so much empty space between the plants.
Light exposure in all gardens is also recorded several times during the day. As trees and shrubs mature, the availability of sunlight changes each year, often affecting the performance of many plants. Very few plants perform well in heavy shade and even some of my shade-loving plants struggled this season due to increasingly low-light from a dense overhead canopy. A little light pruning to thin out some densely branched trees may be done this fall, but major pruning of larger tree limbs will wait until early spring. Fall pruning may initiate soft new growth that can be damaged by freezing temperatures and large cuts may not have sufficient time to heal properly before winter sets in, plus the architecture of trees is easier to view in spring before the trees leaf out.
September is the preferred time of year to install or renovate lawns. Warm soil temperatures facilitate the prompt germination of grass seed and Mother Nature usually assists with consistent moisture. This is an ideal time to patch bare spots, remove thatch, aerate, overseed, spread lime, and fertilize.
Despite an overall good growing season, our recent lack of moisture is beginning to take a toll, particularly on woody plants. Some trees and shrubs are already starting to don fall color, a sign of stress and moisture deprivation. Many of our popular blue and pink mophead hydrangeas are wilted and my astilbes are turning brown. Supplemental moisture is critical at this time of year as many of our woody plants are in the process of setting flower buds for next season, especially mophead hydrangeas, plus astilbes will often succumb if allowed to turn crispy.
Once the gardens are clipped, there is usually new found space to add a few colorful seasonal fall favorites including chrysanthemums, asters, sedums, ornamental peppers, and kale.
— Suzanne Mahler is an avid gardener, photographer and lecturer. She is a member of a local garden club, past president of the New England Daylily Society, an overseer for the Massachusetts Horticultural Society and is employed at a garden center.