by Ron Kujawski

* Plant trees and shrubs through September. When planting, dig a hole 2 to 3 times wider — but no deeper — than the root ball. Loosening soil at the bottom of the hole can lead to too much settling of the tree or shrub. If soil drains poorly, make the hole slightly shallower so that the root ball ends up an inch or two above ground level.

* No frosts in sight yet, but it is September. So, be prepared to protect tender crops from early frosts. What an annoying thought!  Spun-bonded row covers can be used to provide some protection, down to about 28 degrees F. The lightweight row covers can be left on the plants during the day and will allow for some heat buildup before nightfall.

* Perk up colorless flower borders now by planting chrysanthemums. Though the early birds have picked over many of the choicest plants, there is still a good supply available at most retail nurseries and garden centers.

* Check window frames to see if they need caulking or sealing. This is not just to keep you warmer this winter but also to keep out insects looking for a winter home.

* Fertilize lawns. There is no better time than now. If your soils are sandy, use a lawn fertilizer with at least 50% of the nitrogen in a slow-release form.

* Cut back and reshape plants in hanging baskets. Give them a late-season tonic of diluted fertilizer solution, and they may give you one more burst of bloom or fresh foliage before fall.

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Like most folks, I usually leave major work in the perennial garden to early spring. However, September is an ideal month for digging, dividing, planting or renovating. The soil is still warm, and soil moisture levels are usually high. With cool nights and less intense sunlight during the day, transplants are less likely to be stressed. These plants will quickly establish their root systems.

If only a few plants need dividing, as indicated by overcrowding and reduced flowering, dig these up. Then, cut away and save the vigorous outer shoots for transplanting. 

If an entire border needs renovating, tackle this task by doing small sections at a time. It is less foreboding, and if you run out of time, the garden won't be left looking like the aftermath of a rock concert. When renovating, dig up all the plants, except for those which detest transplanting, i.e., peonies and gas plants. Set the plants aside in a shady spot. Then renew the soil by adding organic matter, limestone if needed, and a source of phosphorus such as rock phosphate, bone meal or super-phosphate. Water the soil to help it settle; then replant.   

 Ron Kujawski began gardening at an early age on his family's onion farm in upstate New York. Although now retired, he spent most of his career teaching at the UMass Extension Service. He serves on Berkshire Botanical Garden’s Horticulture Advisory Committee. His book, Week-by-Week Vegetable Gardener’s Handbook, is available here.