By Julie Boudreau
I know I’ve already said that primroses, oaks, walking irises, alpines, rhododendrons, hellebores and fritillaries are my favorite plants. Well, I lied! My favorite plant is the tiarella!
How can you not melt like caramel in the sun at the sight of the small spikes of delicate white flowers of the tiarella? Blooming just after the trilliums, tiarellas are a beautiful find during my spring hikes in the forest. Because the pretty varieties that we grow in the garden all have a little something that is uniquely ours: the tiarella, also known as foam flower, is a plant native to eastern Canada. However, and prepare yourself for a HUGE plant scandal, the heart-leaved foam flower (Tiarella cordifolia) is NOT native to the province of Quebec!
Drama in the Land of Quebec Tiarellas!
What! But everywhere, in horticultural books, they say that the heart-leaved tiarella is a plant native to Quebec. For years, I have loudly proclaimed its native character in my writings. It is sold as a plant native to Quebec. And worse than that, I see it everywhere in the forest. How is this possible?
A few years ago, I experienced a horticultural tragedy when a very talented botanist wrote me a little message to tell me that no… Tiarella cordifolia is not present in Quebec. I went through all the phases of mourning, swinging from denial to negotiation and finally accepting the truth. This tiarella that I have photographed so many times in its natural environment is in reality the northern foamflower (Tiarella stolonifera). My acceptance process ended with several checks, worthy of the incredulous being that I was: the northern foamflower multiplies by leafy stolons! So, everywhere in Quebec, I scratched the layers of dead leaves to check: does this plant have stolons? And from stolon to stolon, my conversion was accomplished.
The plant we’ve always considered native to Quebec, Tiarella cordifolia, is in fact native to eastern North America. However, its natural range does not extend this far north; it is found only in the U.S. states between Maryland and Georgia.
We can still be kind to ourselves, though, because before 2021, several American tiarellas were grouped together under the name Tiarella cordifolia.
A Small, Select Group
The Tiarella genus is not the most prolific in the world’s flora. There are only seven species of foamflowers, but they are distributed throughout the world. For example, Tiarella austrina is concentrated in five states of the American Southeast, Tiarella trifoliata runs along the American West Coast, from Alaska to California and Tiarella polyphylla crosses central China and extends towards the Himalayas and Japan.
As for the northern foamflower, it is quite easily observed in rich forests, both in deciduous forests and in mixed forests. Our native species is very present on both banks of the St. Lawrence, up to about Quebec City. It does not seem to settle much further north than Mont-Laurier. It does not mind settling near a small spring stream and it frequently coexists with trilliums, aralias and ferns.
Growing Tiarellas in Your Garden
The beauty of tiarellas is that they passed through the hands of hybridizers who have developed even more aesthetic varieties. First, the flower, very often white, took on shades of pale pink. Then the leaf returned with more or less deep cuts and the brown spots that generally run along the veins of the leaf were enhanced.
Foamflower remains a small plant, about 20 cm (8 inches) in height and width, and its preference for shady locations is a prerequisite for enjoying the foliage. If it is planted in too much sun in dry soil, the foliage will burn and dry out. Tiarella also prefers soils rich in humus. It is therefore a perfect plant for the edge of a deciduous undergrowth, which is essentially its natural habitat.
Good Companions
Several undergrowth plants coexist very well with tiarellas, including Siberian bugloss (Brunnera spp.), wild blue phlox (Phlox divaricata), violets, bloodroots and small hostas. You can choose to combine them with low ground covers with plain green foliage or with larger plants, such as ferns or astilbes. Since the foliage of horticultural tiarellas is very interesting, it should be surrounded by neutral foliage that will highlight these leaves.
Native plant lovers will combine it with wild ginger (Asarum canadense), trilliums (Trillium spp.), as long as these plants are ethically produced.
A Word About Heucherellas
Anyone who thinks that tiarellas bear a slight resemblance to heucheras is absolutely right. These two plants are part of the same botanical family, Saxifragaceae. In fact, they are so close cousins that it is possible to cross a heuchera and a tiarella together! This results in a variety that does not exist in the wild, the heucherellas (X Heucherella spp.). There are also many beautiful varieties to discover in this group!
Some Interesting Varieties for Nordic Gardens
There are about 30 foamflower cultivars for gardens in Quebec province and the surrounding area. Unfortunately, nurseries often only offer one or two options. Therefore, some of the varieties detailed below will require a little more research to find.
- ‘Appalachian Trail’ – H.: 15 cm (6 inches); W.: 30 cm (12 inches); USDA Zone 4; – White flowers. Well-cut foliage with a very attractive, almost black mark along the veins.
- ‘Happy Trails’ – H.: 25 cm (10 inches); W.: 40 cm (16 inches); USDA Zone 4; – Very pale pink, fragrant flowers. Deeply cut foliage. Discreet markings on the leaves
- ‘Pink Bouquet’ – H.: 40 cm (16 inches); W.: 25 cm (10 inches); USDA Zone 4; – Very pale pink flowers. Prolonged flowering. Deeply cut foliage. Brown markings on the leaves. Bronze foliage in autumn.
- ‘Pink Skyrocket’ – H.: 15 cm (6 inches); W.: 30 cm (12 inches); USDA Zone 5; – Very pale pink, fragrant flowers. Deeply cut foliage. Discreet markings on the leaves
- ‘Spring Symphony’ – H.: 25 cm (10 inches); W.: 30 cm (12 inches); USDA Zone 5; – White flowers with a hint of pink. Prolonged flowering. Deeply cut foliage. Small brown spot in the center of the leaf.
- ‘Sugar and Spice’ – H.: 20 cm (8 inches); W.: 30 cm (12 inches); USDA Zone 5; – Pale pink flowers. Deeply cut and toothed foliage. Beautiful dark red mark in the center of the leaf.
- T. wherryi – H.: 30 cm (12 inches); W.: 45 cm (18 inches); USDA Zone 4; – Native plant of the southeastern United States. Very pale pink, almost white flowers. Slightly cut foliage. Beautiful dark red mark in the center of the leaf.
Although a single foamflower in the garden can be a beautiful sight, tiarellas are spectacular when planted in large masses. So I encourage you to plant dozens of them! It’s particularly for that spectacular mass effect, combined with the delicacy of the inflorescences that tiarellas are my favorite plants… until my next horticultural crush!
Thanks for this very informative and interesting article. Also one of my faves – and yes, they are stoloniferas. But this winter the rabbits decided they liked them too (but this was a hard winter) so the patch was decimated (but not quite depleted), and I’m in Ontario’s banana belt.
Merci! I can’t wait to look for the stolons on my wild-growing Tiarellas when I open my cabin next week in the Laurentians. What do you think of T. Wherry’s (now called t cordifolia var. collina (I am always looking for more Z4 plants)?