September gives us a chance to miss the summer before it’s gone.
The heat is letting up, the evenings are cooler, and we start to anticipate the end of the harvest season. Suddenly, every tomato… every squash is more precious. And once the fall greens begin to come in strong, we can begin combining the bounty of both summer and autumn on our plates. Tomato Arugula salad anyone?
Now we can turn our attention to those jobs which summer’s heat made unpalatable, such as digging new beds or building new garden structures.
With heavy restrictions on indoor gathering this summer, you may have been thinking seriously about your garden’s need for a covered outdoor dining area or pavilion. These structures can help you navigate these restrictions and allow you to experience the last of the season with a small group of the people that you love, regardless of the weather.
Here at Oldmeadow we have used purpose-made polycarbonate sheets to waterproof the area under the deck for get-togethers, and for taking advantage of a rainy afternoon when a little outside time is needed.
I cannot recommend this project enough – it created a ‘room’ where there wasn’t one, and saved having to re-sand the brick patio every few years due to the eroding effects of a dripping deck. I’m also able to leave wooden tables, cushions, ornaments, and coolers outside during the season, fully protected.
After a dry summer, some trees (particularly tulip poplars) are experiencing some leaf drop a little earlier than usual. When a breeze picks up, the yellow leaves flutter to the ground and remind me to soak up every second of the growing season, for it will be over very soon.
“I should have planted that!” for the September garden
Carefully observing neighboring gardens month-to-month allows you to successfully increase your garden’s display season without having to experiment too much with regional timing. Make a note of the plants you love and keep it with you when you go plant shopping during the next planting season.
For the cooler month of September in the Mid-Atlantic, let me introduce you to a native beauty — the late-blooming great blue cardinal flower, Lobelia siphilitica.
Bearing bright blue two-lipped flowers on strong spikes, the great blue cardinal flower looks like it would be more at home accompanying primroses and daffodils in a spring setting, than showing up at the end of the party; but its bloom time is right around now and heading into October.
Much like its cousin, the cardinal flower (Lobelia cardinalis), it prefers moist, loamy soil along stream banks and dappled woodlands, but unlike its cousin, it does not tend to reach and flop when sun levels are lower. As much as I love red flowers, I find I prefer the strong habit of L. siphilitica to L. cardinalis, and I often discover its wind-sowed seedlings growing in both dry and moist areas of the garden.
I had nothing to do with introducing this exquisite lobelia into my garden. It simply showed up in one of my beds – its juvenile foliage looking a bit like evening primrose rosettes. Thankfully I didn’t weed them out. It continues to seed itself here and there, and reminds me that my best laid plans can always be improved upon.
If you’re trying to learn your Botanical Latin, this one is memorable. Yes, the species name reflects exactly what you think it does – it was once used as a treatment for venereal disease – two words I never thought would appear on this site. Deer don’t seem interested in it, but then they’re spoilt for choice.
How to Grow Lobelia siphilitica
The seeds of this lovely native perennial need stratification (a period of cold temperatures), so it makes the most sense to simply scatter them in late autumn, tamping them into a fine soil (and marking the area!). In mid-spring you will see small rosettes of basal foliage emerging. By mid-summer the clumps are larger and a bit taller, but they do not push their weight around, and are easily incorporated into other planting schemes. In late summer, 2ft flowering spikes emerge and are covered in two-lipped clear blue flowers that delight hummingbirds and late-season pollinators.
Outside Tasks in September:
♦The fall garden is here, whether you prepared for it or not. If you have good sized kale or collard seedlings, you should be able to get away with one more planting, but forget about a last sowing of green beans. Garlic should be planted soon for an early summer harvest and you should be able to squeeze in a sowing of leaf lettuce at the beginning of the month.
♦If you have a cold frame, planting lettuce seeds throughout the month can give you a respectable crop of winter greens. Look out for an old duvet or comforter at thrift stores for insulating your frame on cold nights.
♦Bulbs, bulbs, bulbs. At this time of year you can get a respectably-sized daffodil or allium from large chains and independent nurseries, but if you are looking for a specialty snowdrop, you’ll need to get that order in very very quickly. Like yesterday.
♦Great month of the year to build. A shed, a coop, a deck, a fence, a pavilion (as mentioned above). After the winter has had a good go at beating the heck out of pressure treated wood with wind and rain, you’ll be able to stain it in the spring. Always give treated wood at least six months before staining.
♦Time to move those plants you have wanted to move since July. If you want to move zone-marginal plants, trees, and shrubs, (those that are only just hardy in your zone), it’s a good idea to put this off until early spring.
♦If you have a lawn and wish to feed it, now is the time to do so. Re-seeding or sowing a new lawn is also a good job for cooler September days.
♦Test your soil pH and amend your soil as necessary to give the winter a chance to temper additions of lime or sulfur. This is not a job you want to do in the spring – plants can suffer from soil that’s had its pH recently amended.
♦Good time to amend the organic content of your soil with compost or manure, but avoid putting actual fertilizer (organic or non) on your soil till spring. The active ingredients will only leach out over the winter, particularly the nitrogen.
♦Are you a forager? With its kiss of cooler weather and an uptick in moisture levels, September begins the fall mushrooming season. I routinely find wood ears and oyster mushrooms at this time of year. Black trumpets and chanterelles still elude me. If you want to learn more about the history and lore of mushrooming, and get an ID handle on the ‘foolproof four,’ may I suggest Chanterelle Dreams, Amanita Nightmares, by Greg Marley.
Inside Tasks for September:
♦The earlier you can start thinking about your winter refugees (those plants that must be protected indoors) the better. Houseplants that you wish to display should come in earlier rather than later (ficus, schefflera, citrus) to minimize leaf loss.
Start to get an indoor seating arrangement in mind, so all is not chaos at the end of the month, and check and treat plants now for insects like scale and mealy bug to treat BEFORE they come in.
♦If you are potting up smaller plants, rooted cuttings etc… into larger pots for the winter, that plant needs as much time as possible to adjust to a larger pot and put some roots out. Make sure that unplanted pots are kept in a sheltered location with access to natural rainfall.
♦Don’t forget to gather unusual seed heads and dried flowers from your garden for inside decorations over the winter. If you let summer hydrangea heads go late into October, mildew will be the overwhelming theme of all bouquets.
“By all these lovely tokens
September days are here,
With summer’s best of weather,
And autumn’s best of cheer.”
– Helen Hunt Jackson
– from “September”