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.
All the hot weather in July has brought on the bloom of Upland White Aster and very pretty it is, a neat, relatively low-growing aster, with shining white flowers. I thought I had better label my pots of young Upland White Aster, just in case anyone, inspired by the blooming plants in the garden, wanted to buy a few. So, just to be sure of the spelling of ‘ptarmicoides‘, I googled the species. And found out that ‘ptarmicoides‘ is spelled a-l-b-u-m. As in Oligoneuron album.
Yes, Upland White Aster, which long misled us by insisting on actually being a goldenrod, has been renamed from Solidago ptarmicoides to Oligoneuron album. Sigh heavily. It is still a very pretty white aster.
The long, blistering-hot dry period we just went through proved the garden value of a pretty, hardy succulent from the American mid-west. Rock Pink (Talinum calycinum) is a member of a genus which includes some summer-rain-intolerant species from the Rockies, collectively called Fame Flowers.
We are growing Rock Pink for the first time this year. It produces lovely vivid purple pink flowers on long wiry stalks, above the succulent green foliage. The flowers do not open until noon, last only one day, but are continuously replaced by new blooms.
Rock Pink’s home range is Texas to Illinois. William Cullina of the New England Wildflower Society, who is usually a pretty reliable authority, says the plant is hardy in Zone 4 if given excellent winter drainage. A south-facing rock garden would be an ideal home for this plant, in the north. We have recently planted several in groups of five and seven or more in our newly expanded rock garden. With the flowers a bit on the wispy side, they seem to call out for planting in groups. We need some vivid colour and we can certainly use a plant which loves heat in our summer garden. It is visited by bees.
Beaux Arbres has this plant for sale in the nursery, if you would like to give it a try. I cannot absolutely guarantee it will be winter-hardy but it is both charming and easy to raise from seed. It might even spread a bit by volunteer seedlings.
Amorpha canescens A very slow-growing, deep-rooted shrub from the Canadian Prairies, with delightful finely dissected pinnate foliage and spikes of purple blooms in July. It is truly small-scaled, seldom over 18″ high, and thus suitable for rock gardens. Extremely drought-resistant once established. Because of its very slow growth, it is seldom available in the nursery trade.
Beaux Arbres has a few five-year old plants for sale. It is a species we love, and will continue to propagate, but after these older plants sell, it will be five more years before equally large specimens of Leadplant are available again.
Growing conditions: Full sun and well-drained soil.
New Jersey Tea
Kalm’s St. John’s Wort
A really lovely, small, summer-flowering shrub that I am sure many people would want in their gardens, if only they knew it. With fine-textured foliage, a hardy and adaptable disposition, and conical orange seed pods which continue the show through August, Kalm’s St. John’s Wort hardly needs more appeal, but I can add that it is a real draw for native bumblebees.
Kalm’s St. John’s Wort (Hypericum kalmianum) is named for Pehr Kalm, a disciple of Carl Linnaeus, who botanized along the shores of the Great Lakes in the 1740’s. The shrub is almost a Great Lakes endemic – a plant found along the shores of the Great Lakes only — but unlike a strict Great Lakes endemic (Hill’s Thistle, Lake Iris and others), Kalm’s St. John’s Wort is native to in a few other places in the Great Lakes region, including the limestone shores of the Ottawa River. Our seed is as locally sourced as can be, collected from the Ottawa River shoreline in Bristol Township, Quebec.
In the rocky places where it grows in the wild, this shrub is often no more than a foot high. In gardens, it grows to about three feet, as tall as it is wide. It has a preference for calcareous (sweet) soils. Not that it is fussy, but it is not pleased by the acidic soils wanted by azaleas and blueberries. It likes lots of sun.
It is difficult to convey in a photo the great charm of Small-flowered Sundrops (Oenothera perennis). I was heartened recently when some discerning customers at the nursery made a bee-line to it.
Compared to the enormous luminous flowers of Ozark Sundrops (Oenothera macrocarpa), or the great flower masses of citrine yellow of Common Sundrops (Oenothera fruticosa), the flowers of Small-flowered Sundrops are indeed small. However, in a wildflower setting, where its companions might be Hairy Beardtongue or Long-leaved Bluets, the Pointillism-like effect of small dots of brilliant yellow is exactly right.
Beaux Arbres’s stock of Small-flowered Sundrops is from locally-sourced seeds. The plant makes small mound as wide as it tall, studded with brilliant yellow flowers in early summer. The fall foliage is a vivid red. The plant is more tolerant of light shade than you might expect from an Oenothera, sometimes found in open glades in woods.
Another wild rose we are propagating at Beaux Arbres is Shining Rose (Rosa nitida), also known as Maritime Rose. I collected the seed for this species in Nova Scotia. I understand it occurs in Quebec along the Gulf of St. Lawrence shore but it does not occur naturally in the Ottawa valley.
I particularly like this rose for gardens because of its relatively low stature and its fine foliage texture. Its leaflets are smaller and shinier than those of other North American wild rose species, Shining Rose has fabulous fall foliage colour — flaming reds and oranges — and small red hips. Its suckers in loose sandy soil, as do most wild roses, but it is constrained by tighter clayey soils. Topping out at three feet or less, Shining Rose is the ideal wild rose for smaller gardens.