I’ve written about Heptacodium trees before; but perhaps you missed the item
by Art Drysdale
by Art Drysdale


Art Drysdale, a life-long resident of Toronto and a horticulturist well known all across Canada, is now a resident of Parksville, British Columbia on Vancouver Island, just north of Nanaimo. He has reno-vated an old home and has a new garden there. His radio gardening vignettes are heard in south-western Ontario over radio station Easy 101 FM out of Tillsonburg at 2 PM weekdays.

Art also has his own website at

July 22, 2018

Above, One cluster of Heptacodium flowers on my Toronto tree, over ten years ago. Author photo. Below, a medium-sized Heptacodium tree in full flower
photo courtesy of Nancy J. Ondra,




My Heptacodium miconiodes (the seven son flower) is not normally in bloom until mid-September. That name will not likely ring any bells with readers, and that's precisely the reason I'm writing about it. This small tree or shrub has been growing in my front garden in Toronto for three years now and the more I see of it, the more I like it.

The fact that it flowers in September, even later in the season each year than the much-better-known Rose of Sharon, is just one of the plus factors this little-known tree has going for it. Now, the flowers aren't spectacular--small clusters of creamy white florets (in groups of seven--thus the name "seven son flower") somewhat resembling small honeysuckle flowers in spring. The clusters at the ends of the branches, however, are not large--perhaps about a third the size of those on the Japanese tree lilac in June. There is some fragrance but again, not a great deal. Nevertheless, a tree with any kind of flowers in September in our climate is more than worth noting.

Heptacodium is a fast-growing tree/shrub, a native of China, which has been grown by a few nurserymen here in southern Ontario for the last seven years or so. All trees planted thus far survived the devastating winter of 1995-96, so it is obviously hardy at least in southern and south-western Ontario. It is a little better known along the eastern seaboard of the US, and gradually it will become better known here. Just remember you read about it first here!

The bark of my young specimen (just 6 cm in diameter about 30 cm up from the ground) already shows a handsome exfoliating habit during winter months--i.e. the upper "paper" layer of bark which is tan in colour peels back to reveal a darker brown colour beneath.

The tree has other attributes as well. When the flower petals have fallen, the calyces (green lower part of the flowers)--normally falls with petals on most plants stay on and continue to grow while taking on a reddish colour. This, however, is not the end of the Heptacodium's autumn colour! Soon after, fruit develop and these are of an even brighter--red to mauve colour. They do not endure, lasting only a couple of weeks before they turn to a tan colour.

The foliage of this unusual tree somewhat resembles that of the PG Hydrangea, but is slightly larger, and thinner. It takes on a unspectacular yellow colour in Autumn, but does stay on the tree late into the season.

Heptacodium (I prefer that somewhat tongue-twisting botanical name to the lengthy "seven son flower," that accompanied the tree from its native China) is rare still today, and even in China. It came to the attention of the Western world only in 1916, and was introduced into cultivation in North America much more recently by the Arnold Arboretum, Boston, and the National Arboretum, Washington, DC They expect it will be hardy in Canadian zones 5 to 9; possibly a better guideline is that it is likely to be hardy where PG Hydrangea, sugar maple, amur privet, Virginia creeper and Vanhoutte spirea survive.

As already mentioned, Heptacodium may be grown as either a small tree (perhaps reaching a height of seven metres [20 ft.]) or a multi-branched shrub of a lesser height. It is fast growing but mine at least, is not broad spreading. Nurserymen tell me it is tolerant of most growing conditions including wet/dry and acid/alkaline soils. Though it likes sun, it seems to take part shade as mine only gets sun until early afternoon.

Now, that's the good news!

The bad news is availability--I don't know where to tell you to find this tree! And that is precisely why I am writing about it. One St. Catharines Ontario wholesale nurserymen had a modest crop of these three years ago, and couldn't find any retail nursery/garden centre who wanted them. He subsequently sold virtually the entire crop to Germany. There are at least two southern Ontario wholesale nurseries growing small trees, and these should be available as small size specimens soon. Ask the managers at your favourite garden centres--especially if they're people who like to have new plants, to see if they can find it. And, if you don't have success next spring, then try again the following spring.


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