In the garden: September

Wondering what needs to be done in the garden in September? Sharon Hanna spells it out for you in this handy list.


Cover crops, also known as ”green manures,” have been grown throughout the ages by farmers. These plants:

1. Increase organic matter, aiding the soil to hold nutrients.

2. “Mine” nutrients from deep soil to the surface, where they can be used effectively. This way, any fertilizing which has been washed down deep by our abundance of rain can be re-claimed and utilized.

3. Aid in control of various types of soil erosion, for example, on a hillside or bank.

4. Loosen heavy/compacted soil, allowing water and air to enter. – Keep weed seeds from taking hold.

5. Are aesthetically pleasing in fall and winter.

There are four main types of cover crops: legumes, grains, grasses, and “greens”. Legumes (peas, clover, fava beans, vetch) are capable of creating and fixing nitrogen in the soil for plant use.

One added benefit of legumes is that all or part of them may be eaten. The Austrian field pea, for instance, is used by local salad garden marketers as “pea shoots” in their organic salad mix. Greens like Tyfon (a Brassica cross), corn salad, and fava beans, may also be eaten.

Grasses and grains are somewhat less practical for the home gardener, although oats and rye can be used with some success. If you want to keep everything from growing over winter in your garden, try oats. They grow up, then die down and form a mat which keeps out most other vegetation. So cover crops are good for more casual or natural (formerly known as lazy or unorganized) gardeners. Shady spots in your garden? The poetically named “hairy vetch” will tolerate some shade.

Sow cover crops in applicable zones; see Sheena Adams for zone recommendations:

Try Trifolium incarnatum (hardy to zone 5), aka crimson clover. It is stunningly beautiful – large, slightly pointed flower heads, packed with florets which bees and other beneficials make a beeline for. Blooms are deep watermelon-red. You need to plant this by mid-September in zones 6+ – it will overwinter as long as you are not in a very cold frost pocket. The only problem with crimson clover is that you won’t want to dig it into the garden in spring. Feature this plant in your garden for its loveliness, and for IPM purposes. Sadly, it is not invasive! Try growing some in a large pot. It can also be sown in early spring, as an ornamental.

Rather than leave all my strawberries in this year, I’ll experiment, moving them to pots for winter. If you do this, keep them in a sheltered spot – no need for them to be in ‘full sun’, such as it is in B.C. in wintertime, for this period. It seems like a good idea to replenish hard-working soil by growing a cover crop like winter rye, field peas, or broad beans where the strawberries have been for a couple of years now. Fall is an excellent time to plant raspberries, blueberries and other small fruit from cuttings or seedlings.


In cooler zones of B.C. it’s time to give roses a light cutting back before winter sets in. Go easy, saving hard pruning for spring. If you live in an area with a lot of heavy winds (this is now so even in Metro Vancouver at times). Janet Wood, rose expert, suggests that you mound soil up slightly at the base of roses, and heel in (press down) with your gumboots. This prevents rocking and rolling in the wind – which roses do not like.


If you haven’t made pesto yet, be sure to use your beautiful basil before our temperature fluctuations start affecting the leaves – they seem to begin to turn black with the dampness and cold, and evenings have been very cool. There are thousands of recipes for pesto and other ways to preserve basil – check out my blog on how to freeze it in batches without using plastic.

You can take cuttings from woody perennial herbs this month (the earlier the better). Suitable candidates are the hardier ones like thyme, rosemary, oregano, marjoram. Place several in 4 inch pots, adding very little water to fast-draining soil mix containing perlite. Cover with plastic wrap, or cover with a plastic dome. These will work well in an unheated greenhouse on the coast, or a slightly heated one in coldest zones of B.C.

Cut back tarragon, and make tarragon vinegar. Remove and discard main woody stems, and place the leaves and smaller stems in a jar, cover with good-quality white wine vinegar, cap, and store in the dark for three weeks. It’s best then to strain and remove the leaves. This stuff keeps for many years in a cool dark place, sealed in mason jars. Use it in vinaigrettes, sprinkle on any chicken dish – lots of ways to use it. Or, give it away as gifts.

If you’d like to increase tarragon in the garden, dig the clump early this month (after cutting back to make vinegar or to use in other recipes – fresh as tarragon does not dry particularly well) separate or cut the root into pieces, and replant. Do not do this too late or you’ll lose them all – tarragon is not all that easy to get established. Did you know that tarragon evidently uses up elements in the soil quickly? It’s indeed a heavy feeder, unlike most perennial herbs. Keep that in mind in spring, when tarragon emerges, giving it a side-dressing with something rich.

Speaking of tarragon, always look for genuine “French” tarragon. You’ll sometimes see one that is very big and tall and skookum looking, sometimes called “Russian” tarragon. It has little or no flavour, and grows like a weed. French tarragon tends to be more discriminating, and usually doesn’t grow more than a foot or so tall.


Put windfall apples around tomatoes that are not ripening. Ethylene gas helps fruit ripen. Put the rest in the compost, or if you are patient, make apple sauce. Give apples away to neighbours and friends (you are likely already doing that!), slice, core and dry in your dehydrator, make applesauce.

Still have lots? Contact your local fruit tree sharing project – they are active in Richmond, Nelson, Vancouver, and Victoria. Go to GardenWise editor Carol Pope’s blog Sharing the Harvest for more on this. Perhaps you could start one in your area if needed! What a great fall project to do with friends.


Late this month on the coast, earlier in cooler zones, begin to plant spring-flowering bulbs. Allium provide excellent value for the money spent, naturalizing if they’re happy, providing impact over a long period of time. From emergence through bud to bloom, even in dried seedhead they’re always eye-catching. As with all bulbs, it’s a good idea to plant in groups of 5 or more for effect. Grow close to your food garden (or right amongst the veggies) – their multiple “floret” flower heads are powerful beneficial insect attractors.

Size matters when it comes to bulbs; shop early for good selection – the biggest and best sell quickly. Larger bulbs contains more carbohydrate (of which the flower is “built”) and likely already has pre-formed stem tissue inside. Spectacular looking and healthy flowers grow from big bulbs. Speaking of bulb selection, when you reach into those bulb boxes to search out the “biggest,” be sure to wear gloves when handling Hyacinth, some other bulbs – they can cause skin irritation that is rather painful.

Though tulips are associated with Holland, they were introduced to China and Mongolia by the Turks, eventually making their way to the Netherlands several hundreds years ago. Try the “Impression” series – particularly Pink Impression: very long-stemmed, mid to late-season flowering, huge “cups,” vivid, true pink. Another one I love is “Verona” – early, double, delicate cream, looking a bit like a peony. Here’s an image.

Neither will naturalize (grow/multiply), at least they haven’t for me. Look for the word “naturalizing” or “species” on the label if you want your tulips to come back year after year. Naturalizing types tend to be early-flowering, and usually have smaller blooms with the exception of Kaufmanniana series – of which there are many! These waterlily-types re-occur well in my front yard. Click here are a whole lot of images.


On the coast, as early as possible this month, make haste to direct-sow arugula, mizuna and other Asian greens, mache, kale, Giant Red mustard, endive/escarole, scallions (green onions), and spinach. If you’re in a cooler zone, especially if you have raised beds, give it a try – using floating row cover to keep the heat in at night, or other method of cloche. Of course if you have a cool greenhouse, that works too!

Plug in some organically-grown shallots (from the store, if you don’t have your own homegrown ones) for fall ”green onions.”

Because of the “growing” popularity of food gardening, I’m hoping garden centres will have winter veggie transplants for leeks, broccoli, kale, chard, etc., if you haven’t had a chance to start them yourself. If they don’t, be sure to mention it to the nursery manager.

Begin to plug in your homegrown fall/winter vegetable starts, as spots become vacant in your garden.

Continue to save seeds…..hang seed-stalks somewhere dry and not too hot or cold. If it’s raining a lot (as it is now on the coast)….do not worry too much. Nature has provided pretty good protection for seeds – they’re able to withstand a lot. Do, however, gather and bring indoors before they get moldy.

Take cuttings from: Artemisia, boxwood, coniferous evergreens, Erica (heather), Forsythia (eek!), perennial Fuchsia, Hebe, Hydrangea – you can see where this is going – along with a whole lot of woody-type perennials. If you’re interested, Creative Propagation: A Grower’s Guide, written by Peter Thompson, is a fantastically complete resource. Avoid the brand new reprint (with a different cover) which omits the alphabetical Latin list which I find entirely useful.


In cooler zones, bring houseplants back into the house. If you have had to turn the furnace on already, bring the plants back in gradually, just as you hardened them off to bring them outdoors. This will minimize stress. Don’t overwater them at this time, and keep away from blowing hot air from furnaces – especially Ficus benjamina – notorious for losing its leaves for just about any reason. They hate draughts – cold or hot.


Irrigate when needed, but slowly reduce watering so plants get ready for winter. Watch your plants and notice what they are doing, then take your cue – continue to water fall-bloomers. Don’t water plants that are obviously waning or dying back. They don’t need water at this time.

After periods of heavy rain, notice where water accumulates in your garden. Improve drainage by digging, adding rocks, sand – various methods. Or, love it the way it is, and transform the area into a bog garden with marginal water plants!

Divide and move dormant perennials now. If you like, add a handful of kelp meal to encourage healthy root development.

I recently had a large, unwieldy Forsythia removed this summer – there are so many all around the neighbourhood and though they are a beautiful harbinger of spring, it was time for a change! In any zone, this is a great time to rethink your garden, replant, reposition various plants, move or get rid of that shrub that is bugging you or that is more “tree-like” than a shrub and it was really inappropriate for the space. Moving and/or dividing plants this month allows them to adjust and get a foothold over winter, and they’ll increase in size more quickly than if you waited to divide in spring. Do this at least three weeks before hard frost in your area.

Check local garden centres for bargains in the perennial/shrub department. If you know what you want, don’t be discouraged by what looks like a half-dead, scraggly plant. Just check to make sure the roots are fine, and get it into your garden now. If possible, plant in threes (at least) unless it’s a giant Miscanthus – you’ll be glad you did.


September is usually a great month to seed lawns, or patch – roots form quickly, and grass grows better with the cooler nights. Do not over-fertilize now. This causes weakness in any plant, and grass is, after all, a plant. Plants need to be hardy on their own to withstand cold temperatures, frost, etc.

Consider converting part of your lawn to veggies or small fruit. This can be done easily – check our Carolyn Herriot’s blog on “lasagna garden”. Not about growing Italian vegetables, “lasagna” refers to layering organic material right on top of lawn – no digging required – to create a garden bed easily and quickly. Another good thing about this type of bed – critters like slugs and sowbugs can’t get into the edges like they do in raised wooden beds, so they won’t be making nightly visits to your lettuce.

Those not interested in growing food at this time may want to convert some lawn areas into mulched garden beds. Plant up with drought-tolerant perennials, suitable native plants, shrubs!