New for 2021: Goldthread

The very glossy, evergreen leaves of low-growing Goldthread (Coptis trifolia) are most attractive, but before you start thinking this may be the ideal shade-loving ground cover for your shady garden, be aware that this little cutie demands a cool, acidic organic soil, and is not suited for warm urban conditions. It grows in damp moss under conifers and it sometime covers very old, decaying stumps, to lovely effect. When I lived in Toronto, I became accustomed to seeing Goldthread in only the coldest and most organic spots. So I was delighted, and a bit surprised, to see Goldthread in a woods near Beaux Arbres, romping along the side of an old logging track, in partial sun no less, forming an extensive low ground cover, even weaving in and out among the grasses and hawkweeds and other weeds in the trackway, finding the ordinary leaf litter and needle duff sufficiently organic for it to thrive. It is worth remembering that, compared to almost any spot in southern Ontario, this old track has cool and acidic soil. Still, it showed what is possible in the Ottawa area, if the right conditions for Goldthread are present.

Goldthread blooms in early spring. The pretty white flowers, with a boss of white stamens, are very briefly open. The white petal-like parts are actually sepals, and the true petals are modified into yellow nectar cups. If you can catch its very brief flowering, it is worth giving the flowers of Goldthread a close look. I have not been able to find out much about Goldthread’s pollinators but those little cups, brimming with nectar, suggest it is an important food source for somebody.

The plant spreads by thin rhizomes, which are bright yellow, and give the plant its common name. An older botanical name is Coptis groenlandica, the reference to Greenland giving us a clue to its preference for cold places.

Goldthread is one of the little woodlanders I will have in small quantities this spring. Although indisputably native to the Ottawa area, it is so little adaptable to urban conditions, I find it difficult to guess what the demand for it may be. Away from the downtown heat island, in a very well shaded garden, it might be worth trying Goldthread in, say, a wooden trough filled with a specially prepared soil mix (lots of well-rotted needle duff), with other charming miniatures, such as Common Wood Sorrel, Creeping Snowberry, and Bunchberry.

New for 2021: Starflower

The tiny white seeds of Starflower (Trientalis borealis) are easy enough to collect but I did not have great success germinating them. So I have only a handful of plant available for Spring 2021. I have no idea how popular this quiet but charming little woodlander will be. I can imagine folks who love the north woods might like it. It seems quite adaptable to a variety of shady situations, under conifers and deciduous trees.

Starflowers grows scattered throughout the woods at Beaux Arbres, in sites both moist and dry. (The soil at Beaux Arbres is mostly sandy and moderately acidic.) Their stems of whorled leaves resemble another woodland plant, Indian Cucumber Root (Medeola virginiana) but Indian Cucumber Root is much less common in our area, and occurs almost exclusively in relatively rich, moist bottomlands. In our woods, Starflower never masses to make a notable floral display. I don’t know if it is possible to coax it to do so in a garden situation. Worth trying, for the little starry blossoms have a lovely simplicity. They are also botanically interesting, for they are one of the very few flowers which have seven petals.

The indispensable William Cullina, who is only garden writer I know of who has taken Starflower seriously, has this to say about it:

[I]t adds a note of diversity and authenticity to naturalized plantings and woodlands, and I think it looks lovely growing among mosses, wintergreen, partridgeberry, and others.

The New England Wildflower Society Guide to Growing and Propagating Wildflowers of the United States and Canada, 2000.

Starflower has recently been put into the genus Lysimachia, with the yellow-flowered native Loosestrifes, such as the very pretty native Swamp Candles (Lysimachia terrestris). Thus Starflower should be properly called Lysimachia borealis, but most books and websites will have it listed as Trientalis borealis.

Feature photo, above: Matthieu Gauvain via Wikimedia Commons

New for 2021: Partridgeberry

Partridgeberry is one of the low evergreen vines that cover the forest floor in northern woods. It can easily be distinguished from Twinflower, Trailing Arbutus, and Wintergreen by the distinct pale midrib down the centre of each leaf. Although Partridgeberry comes into its own in damp conifer woods, it is also found in mixed forests, which suggests it is not quite as dependent on strongly acidic soils as the others.

Beaux Arbres expects to have Partridgeberry plants available in the spring. Last summer, when walking through the woods of our good friend on the next concession, I came across an enormous, dense patch of Partridgeberry, forming a thick and extensive ground cover. I had never seen such a lush display of this plant and it required that I re-evaluate my opinion of Partridgeberry’s potential value in the garden. Margaret generously allowed me to take cuttings from this patch (which didn’t make the slightest dent in its abundance) and as soon as they are well rooted, I will offer them for sale.

I prefer to grow from seeds, which creates genetic diversity, but for a few of the sprawling woodlanders, which are slow from seed but easy from cuttings, it is just more practical to propagate from cuttings. Creeping Snowberry is another little evergreen that is much easier from cuttings. If I can ever offer the handsome Pipsissewa (Chimaphila umbellata) — a long-term goal, not imminent — it will have been propagated from rooted offsets, as this glossy evergreen ground cover plant is impossible to grow from seeds in cultivation.

Although only a mile away from us, the headwater wetland in the woods behind Margaret’s farm is wetter and more acidic than almost anywhere on our farm. Some beautiful little plants, such as Bunchberry and Trailing Arbutus, flourish there, but the cold, organic, acidic conditions gives us clues as to why these lovely plants can be challenging to establish in urban gardens.

Feature photo, of Partridgeberry, above: Ryan Hodnett, via Wikimedia Commons

Back for 2021: Virginia Waterleaf

The nodding flowers in mid to late spring are modest to our eyes but extraordinarily attractive to all manner of forest pollinators. Although usually pale lavender in colour, the flowers of Virginia Waterleaf in the wild can be pure white, a nice mid-range purple, or pale pink. The distinctively lobed leaves emerge in the spring spotted with silver. It is the silvery spots which give the plant the name Waterleaf. Alas, the pretty spots fade as the leaves mature.

Virginia Waterleaf spread by rhizomes and by seeds so, where it is well suited, it can easily form a robust ground cover. It prefers dappled deciduous shade and it is tolerant of heavy clay soils. Thus it is an excellent choice for shady city gardens with compacted soils. If summer droughts have left the foliage looking tattered, the plants can be cut down and they will produce a crop of fresh leaves for autumn.

Good companions for Virginia Waterleaf might be White Snakeroot, Wild Geranium, and Zigzag Goldenrod.

New for 2021: Canada Mayflower

Canada Mayflower is such a small, ubiquitous woodland plant, it is easy to take it for granted. It grows in just about every kind of forest, in every kind of soil, and is one of the few natives that manages to eke out some sort of straggly existence in spruce plantations. It is a great colonizer and, with so much of its energy going into vegetative spread, relatively few of the leaf clusters will put out a flowering stem.

Canada Mayflower grows in all the forest areas at Beaux Arbres. Although I am very conscious of the demand for adaptable, shade-tolerant plants for city gardens, Canada Mayflower seemed just too trifling to cultivate. I have overhauled my opinion. There is a spot beside the side road where I walk Kapik nearly every day, a damp depression in deep shade, which is thickly carpeted with Canada Mayflower and it slowly dawned on me that, there, Canada Mayflower made a handsome ground cover with two seasons of interest.

Canada Mayflower is closely related to False Solomon’s Seal, which has more history as a garden flower. Like False Solomon’s Seal, it has a sprig of small, sprightly white flowers in late spring. Despite the common name, Canada Mayflower is more likely to be blooming in June in our part of the world. As summer comes to a close, each flower stalk bears a small cluster of bright red berries.

Another common name for this plant is Wild Lily-of-the-Valley, from the similarity in leaf shape and colonizing habit to the European garden plant. Unfortunately, the existence of this name has misled many into thinking that the non-native, indeed invasive, Lily-of-the-Valley is a native species that can be introduced into woods. It is not. I love its fragrance, muguet, and if there were a way to safely contain the plant, I would grow it, to pick little nosegays to bring into the house. Alas, there is no safe way to grow Lily-of-the-Valley if you are near native woodlands, as it spreads both by rhizomes and by seeds contained in the poisonous red fruit. (Note: the fruits of Canada Mayflower are not toxic. Not tasty, but not poisonous. Some years they disappear quickly as they are eaten by many species of birds.)

Another consequence of my lack of serious attention to this plant is I do not have a good photo of it of my own. The feature photo above is by Blue Canoe from Wikimedia.

Great Plants for Shade

I love Spikenard (Aralia racemosa), a big shrub sized perennial. The flowers are not much, small and greenish white, but the bold leaves and dark purple stems are handsome enough throughout the summer. It is in the autumn that the plant shines. The little white flowers develop into red berries that turn black when fully ripe. The little fruits grow in large showy clusters.

We grow this shade-loving forest plant on the north side of our barn, where we need something large to be in scale with the wall but where any woody shrub would get crushed in the winter by snow and ice crashing off the barn roof. The herbaceous perennial Spikenard is safely underground for the winter.

Spikenard fruit is appreciated by birds. Spikenard is fast-growing for a shade plant, and it will bear fruit in its third year from seed. If you have a shady spot and want to provide for birds, a planting of Spikenard will reward you and the birds sooner than most shade-tolerant shrubs.

Very few wildflowers for shade have large showy flowers. Producing big flowers is just not in the energy budget for a plant that survives on the scraps of sunlight that the canopy trees miss. What they lack in size, forest wildflowers make up in charm. The bright pink flowers of Panicled Tick-trefoil (Desmodium paniculatum) are a fraction of the size of those of its meadow-growing relative, Showy Tick-trefoil (D. canadense). They are, however, held upright in dainty, airy sprays, which maximizes their effect. Both of these wildflowers from the Pea family are attractive to native bees. Both also have sticky seeds, the tick-trefoils, so its is wise to site the plants carefully, away from paths where the family pooch walks.

New to me this season is American Ipecac (Gillenia stipulata). This plant of oak savannahs and rocky glades does not occur in the wild in Canada; native to Michigan and New York State down to Texas, it is adapted to drier conditions than its close relative Bowman’s Root (G. trifoliata). It has more finely divided leaves and very similar starry white flowers. Not for deep shade, but it will likely prove to be a useful addition to the roster of plants for dry, dappled or part-day shade.