September is the last month to enjoy the garden. Annuals and asters have taken center stage. Roses and some perennials are in the midst of their second bloom. It’s almost the end of the picnic season. Mosquitos are replaced by bumblebees, and picnics become an exercise in evasion.
The color combinations so carefully planned for spring and summer are now giving way to the overall anticipation of autumn, when the trees turn russet, gold and brown. Even the deep reds and purples which seemed harsh in spring look fine in September.
Enjoy the particular clarity of the September light. You can ignore a certain disorder in the garden, unacceptable in spring, but the norm in September. Untidiness is forgivable in September, because by next month the ferocious pace of bulb planting will be underway, and once that is complete the garden must be put to bed. But for the time being enjoy September; it can be the most restful month in the garden, or the best month for some hard work. It’s your call.
This is a good time to shop, as the end-of-year sales at nurseries will be in full swing. While nurseries can easily hold over larger trees and shrubs until next spring, to carry smaller materials over the winter becomes costly.
City gardens are perfect for small bulbs. Try the smaller members of the daffodil family, the cyclamineus and jonquillas. Don’t forget snowdrops, crocus spring and fall, and colchicums.
Each year at this time I wish I had a Clematis paniculata, the autumn-blooming cascade of starry white flowers covering everything in sight.
|Sweet autumn clematis|
September is a good time to order clematis, for they are rarely shipped after mid-October. If you plant clematis in the fall, they will get off to a robust spring start and you will surely have blooms next summer. If planted next spring, you are likely to get only foliage.
Most perennials will welcome division now, but some definitely will not. These include phlox, Shasta daisies, and Siberian and Japanese iris. Don’t even try.
The Japanese anemone is the queen of the fall garden. Starting from a clump of basal leaves it will grow to three feet bearing several weeks of white or pink silver-dollar size flowers.
Other September bloomers are False Dragonhead (Physostegia virginiana), Brown-eyed Susan (Rudbeckia trilobum), Bluebeard (Caryopteris x clandonsis), a low-growing blue shrub better treated as a perennial, Sneezeweed (Helenium autumnale), and Rubeckia ‘Henry Eiler' (R. subtomentosa).
If rainfall is adequate, little watering will be needed from now on. The exception is new plantings and of course roof gardens which will need watering right up to hard frost.
Bring in pots of amaryllis that have been summering indoors.
Trim long stems of perennial vines and tie up or train as you like.
Cut back iris foliage to three inches
Don’t let phlox go to seed or they will self sow, reverting to their original magenta and the new seedlings will crowd out your carefully cultivated varieties.
Last call to bring the house plants indoors.
Pull out vegetable plants when all the crops have been gathered and plant a winter cover crop. Winter rye or small grains are good in our region.
Fertilize lawns and sow seeds in thin or worn areas.
You can still plant perennials, but they will have to be protected against the winter’s alternate freezing and thawing. More on that in November.
Start cutting back perennials. You can compost all but the leaves and stems of the peonies. These you must discard or burn.
This is the best time to plant daffodils, although almost everyone waits at least until October, and often drag their feet into November. Start early, and give yourself a gift for 2015.