Late Colour in the Hoop House

On a dreary November day, with the golden tamaracks providing the only colour in the landscape, the interior of the hoop house is only a couple of degrees warmer (still quite chilly) but colourful fall leaves still linger. The brightest colour comes from the leaves of Wild Geranium. I like the green and red carpet of Prairie Smoke. The lovely soft apricots of Bowman’s Root have mostly faded to brown but one plant is still glowing.

September Highlights

Rock Pink

Rock Pink (Talinum calycinum) has been in bloom for weeks and it just got better and better, as long as the warm weather lasted. I love the bright magenta of the flowers against the natural greys of the rocks and stone mulch. I hope it proves to be hardy, here in western Quebec, but even as an annual it is worth growing for mid to late summer colour in the rock garden. Small bees love the flowers.


A useful contrast to all the tall yellow daisies, the bright saturated purple of ironweed (Vernonia sp.) glows in the autumn sunshine. This plant is tall and rugged.


Ironweed and Switch Grass.

Tall Sunflower

Of the many tall yellow daisies for late summer and early autumn, my favourite is Tall Sunflower (Helianthus giganteus). It can be very tall – to 3 metres. That’s a plus. If you are going to do tall, do it! Even small gardens have lots of room in the vertical direction. Tall Sunflowers flowers are a lovely clear yellow and the purple stems are a nice contrast. On warm afternoons the plants hum from the volume of pollinators. After the flowers fade, the seeds are relished by goldfinches.


Heart-leaved Aster

Now, I warn customers that pretty Heart-leaved Aster (Symphyotrichum cordifolium) is a pushy native that spreads, but let’s face it: most gardens have spots where a tough, pushy plant is just the thing. We have an ancient clump of common lilacs, as do most old farmyards. The lilacs are fragrant and lovely and visited by Canadian Swallowtail Butterflies, for about a week in the spring, and then, for the rest of the summer, they are a big, boring green lump with no fall colour. Heart-leaved Asters are willing to grow in the dry root-filled conditions under the lilacs and bloom in a beautiful pale blue ruff at their feet. Like other asters, they are important for late-season pollinators.

Closed Gentian

Daisy-form flowers dominate late-season wildflower gardens. Native plants with distinctive and unusual flower shapes are always interesting and even more welcome when they bloom in the fall. This is a white-flowered garden selection of the native Closed Gentian (Gentiana clausa).




Giant Swallowtail Caterpillar

First spotted as a tiny hatchling, by Mo Laidlaw, about three weeks ago, this caterpillar of Giant Swallowtail seems a little bit bigger each time we check on it. It had eaten all the leaves on its seedling Hop-tree (Ptelea trifoliata) so I moved caterpillar and denuded seedling into the hoop house underneath a larger Hop-tree. The caterpillar moved over handily. We hope that the added protection of the hoop house will allow it to get up to size before cold weather sets in. This species overwinters as a chrysalis.

Giant Swallowtails have only recently moved north to the Ottawa Valley. They are still an unexpected sight this far north. They are the largest butterfly in Canada. Their caterpillars eat plants in the citrus family. Prickly Ash (Zanthoxylum americanum) and Hop-tree are the host plants in Ontario. We saw what was probably the mother of this cat checking out the Gas Plant (Dictamnus), a decorative European flower in the citrus family, in our garden but it seems she preferred the Hop-trees in our nursery for her nursery.

Prickly Ash is common in some parts of the Ottawa Valley, especially on calcareous soils, but it is a large, thorny, suckering shrub unsuited to almost all gardens. The Hop-tree, native to the Carolinian zone of southern Ontario, is a neat, non-suckering, tree-like shrub with scented flowers. It is hardy as a garden plant in the Ottawa area and is a more attractive option than Prickly Ash for gardeners wanting to entice beautiful black and yellow Giant Swallowtail butterflies to their gardens.

We Recycle Pots

We recycle our nursery plastic. If you have a potting shed full of pots looking for a good re-use, consider bringing some when you visit Beaux Arbres.

We do not use or want: Compostable pots (speckled brown), cell packs or flimsy pots, pots in vivid colours, or rigid round green pots. We use a few round green and vividly coloured pots in seeding but we have enough, thanks. What we really like are:

  • 2 1/2 ” tall square in black
  • 4 1/2″ tall square in black
  • 1 gal and 2 gal nursery cans (mostly they just come in black or sometimes grey)

Why can we recycle pots while most growers do not? Growers of annuals start their plants in heated greenhouses in February or March, which are difficult conditions, and they are quite rightly very afraid of introducing diseases of any sort via inadequately cleaned pots. I like being able to go to the garden centre and select a few colourful annuals already in bloom for my hanging baskets, and possibly you do too. So let’s not be too critical of the growers who enable us to do this. (And let’s shop at local producers.)

At Beaux Arbres, we are growing wild plants, mostly perennial, and we start nothing ahead of its season. The plants we bring to the spring sales were started May or June of the previous year. As seedlings, they would be starting in ordinary soils in nature, and if they don’t have defences, they aren’t going to make it with us. We also grow a large variety of plant in small quantities — diversity gives resilience. We are not growing named cultivars but species, with genetic diversity. We do not attempt to grow orchids or others very fussy plants.

We do clean, very carefully, our pots for re-use. Its is labour intensive and not economically justifiable. We re-use out of our environmental commitment.

Wild Senna Beats the Heat

This tall yellow wildflower loves the heat and seems to laugh at drought. Five or six feet tall on sturdy stems, Wild Senna (Senna hebecarpa) has typical pinnate Pea Family foliage but the individual flowers are more open than typical in the family. Wild Senna belongs to an early-evolved branch of the Pea family tree. The open flowers are very appealing to large bumble bees. fullsizeoutput_3f0

We have also seen hummingbirds visiting the Wild Senna flowers this year. Our hummers are foraging hard this season because so many of our cardinal flowers, the hummingbird favourite, died in the drought, and the wild Spotted Jewelweed along the seasonal stream is a fraction of its usual self.

Wild Senna does not occur in the wild in the Ottawa Valley — it hails from a little further south and occurs in southern Ontario south of Brantford. A lovely yellow butterfly whose caterpillars rely on Wild Senna — the Cloudless Sulphur — also occurs south of here. Wild Senna is an acceptable host plant for some other butterflies, including the Silver Spotted Skipper, that eat a diversity of native plants in the Pea Family, We have an abundance of Silver Spotted Skippers because we have a lot of their main host plant, Black Locust. I would never recommend planting Black Locust, which is an extremely aggressive suckering tree and thorny as all out. We are trying to beat back our Black Locusts. It is nice to know that if we ever succeed in eradicating the Black Locust (not too likely) we can still provide for the Silver Spotter Skippers with a handsome and well-behaved herbaceous flower, the Wild Senna.

Plant Wild Senna at the back of a sunny border. After the flowers finish. thin black pods remain decorative through the autumn. This plant does not need staking, fertilizing, or dividing. It consorts beautifully with tall ornamental grasses.


Miniature Crevice Garden

This hypertufa trough, planted only weeks ago, is doing remarkably well. I used a technique I read about in the North American Rock Garden Society quarterly, and sandwiched  a thick clay mud between vertical slabs. One would think that the little Erigeron pinnatisectus or Feather-leaf Fleabane, perched at the top, would not have had a hope of surviving, but this is a plant of steep slopes and high ledges, and it seems to be thriving. Let’s see how this little garden survives the winter.