Northeast Gardener's September Checklist

September is my favourite time of year certainly. Gardens anyplace have matured and are thrown out on sidewalks and over fences, and therefore are generally looking very lush and abundant with eye-popping annuals, textural grasses and herbs. Weekly visits to the farmer’s market are a joy, since there’s just so much to look at and to buy.

There’s also a lot to do to keep matters under control and looking their best. My garden carts are crucial as I begin the work of cutting back perennials, adding into the compost pile and hauling loads into the trunk of the lawn.

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Welcome wildlife with blossoms. Many wonderful annuals are hitting their peak today, like this sunflower, that has multiple blooms on strong stems.

Apart from producing a fantastic cut flower, sunflowers are still an essential food resource for pollinators; their seed heads could be left position to attract finches and other birds.

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Late-blooming perennials, like aster and obedient plant (Physostegia spp), take center stage and lure in migrating monarchs, who proceed across the area in their way to overwinter in Mexico.

New England aster ‘Alma Poetschke’ (Symphyotrichum novae-angliae ‘Alma Poetschke’, zones 4 to 8) is a standout.

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Another fantastic plant for extended bloom period is mountain fleece flower (Persicaria amplexicaulis ‘Firetail’, zones 4 to 7), a native perennial with terminal spikes in shades of pink and raspberry.

It is especially great for wet soils and onto a woodland border, or in sensible borders with vibrant zinnias.

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Summer would not be summer without zinnias. I start them in the greenhouse in April, babying them as transplants, and by mid-September they’re huge and have to be encouraged with canes or twine tied to fence posts across the vegetable garden border.

Only today a Tiger Swallowtail butterfly hovered nearby, collecting nectar onto a large white zinnia.

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Add late-season texture. Grasses are in full glory in garden centers this month, so take a peek at what’s available and consider adding some to your own garden. They unite to earn a living sculpture. Tall varieties look especially great against a hedge, fence or wall.

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The colors of grass appear to change from day to day — the seed heads are brownish, and then the foliage begins to yellow and darken into shades of caramel and rust.

Here fountain grass blends superbly with willow blue star (Amsonia hubrichtii, zones 4 to 9) in my Vermont garden.

Some other favorites for fall feel are switch grass (Panicum virgatum ‘Heavy Metal’, zones 5 to 9), little bluestem (Schizachyrium scoparium ‘Blaze’, zones 3 to 9) and feather reed grass (Calamagrostis acutiflora ‘Karl Foerster’, zones 5 to 9).

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Reap the crop. The craze for green smoothies is big where I live. In case you have a high-caliber blender and grow carrot, carrot, celery, lettuce, arugula and beets, you can earn power meals that will make you feel superhealthy.

Even without a blender, all of these are great for you, so get busy in the kitchen and eat your own sauce. Sow seeds of cool-season plants today for a late crop.

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Tomatoes are plentiful and hard to withstand this month. I’m savoring the fruits as they ripen on the vine.

Here in the Northeast we have a short growing season. Indeterminate tomatoes will produce fruits for an extended period — for many this is actually the highlight of summer!

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Feed the birds with fruiting shrubs. Concerning this time of year that I notice an increase in bird activity in my mixed border, where viburnum and redtwig dogwood offer a privacy screen from the street.

Viburnum ‘Mohican’ is especially showy, with veggies moving from red to black and leaves that turn reddish with the shortening days.

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Another fantastic wildlife shrub would be aronia (Aronia arbutifolia ‘Brilliantissima’, zones 4 to 9), commonly referred to as chokeberry. You can’t beat it for fall color, and also the fruits persist into fall.

Other garden actions this past month:
Cut back perennials.Trim hostas along with daylily scapes.Plant mesclun, lettuce, arugula, kale and other cool-season crops.
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