Tuesday, 31 July 2012

Eurybia divaricata (Aster divaricatus)

The white woodland aster, or eurybia divaricata, is a quiet beauty. It has sprays of white, starry flowers from June to October in England, from late summer through the fall in North America. 

Eurybia divaricata Aster divaricatus
Eurybia divaricata, photo by Tom Potterfield, Creative Commons
The leaves are heart-shaped, with a slight twist at the pointed end, as if someone had tweaked them. They also have a surprisingly spring-like fresh green to them all season long. The purple-black stems are twisty, with the flower sprays pointing this way and that. These stems are what give the plant part of its name, since divaricata means "straggly, sprawling, or spreading". The leaves and stems have also provided common names for the plant: Heartleaf Aster and Serpentine Aster.

It is native to eastern North America, all the way from Ontario and Quebec down the eastern half of the continent, although it stops short of Florida. As you might expect from the name, eurybia divaricata is a woodland plant, favouring open, dry woods. It is a survivor, which sends down roots all over and sprawls its way into whatever sun is available. Tidy-minded gardeners deplore its sloppy posture and try to stake it, but the best way to handle it is to find a space where nothing wants to grow, and let it flop all over it. When you see how gracefully the leaves and flowers deploy themselves along the dark, twisting stems, you'll know you were right.

Eurybia divaricata flowers, by eleanord43

I had mine between my buddelia (butterfly bush) and the fence, an area previously colonised by weeds as little would grow there. The aster, and some red-leaved epimediums (barrenwort) filled in the space beautifully.

Wood aster also has gardening guru Gertrude Jekyll in its corner. She used it with bergenias as path edging, the aster spilling over the leathery leaves. Apparently she found the contrast between the delicacy and cloudiness of the aster and the glossy solidity of the bergenias appealing. I suspect that Europeans have taken this plant into their gardens in a way that North Americans, who after all see it in the woods everywhere, have not.

New Name

You may be thinking that it's time for a digression on plant names, and you would be right.The wood aster has fallen afoul of two different botanic quirks. 

The first is that whoever named a plant first has priority, and their name stands. In this case, while Linnaeus referred to this plant as an aster, the wood aster has been shown the door, and Alexandre de Cassini gets a chance. 

His choice for the wood aster was eurybia, from the Greek ευρυς (eurys), meaning wide, and βαιος (baios), meaning few. So when it was decided that all the North American asters were no longer asters, Cassini got his posthumous wish. (Small rant: the North American aster have been divided up amongst 10 different species, all of which have names like Oreostemma and Symphotrichum. Aargh.)

The second is that botanists are either lumpers or splitters. For a long time asters were lumped, that is, they were all put in the same group based on very superficial criteria. But now it seems that the splitters are in ascendant, and only Old World asters are still allowed to be asters. So our wood aster is now a eurybia.
Wikipedia Commons

But Eurybia was also a goddess. Or, more accurately, she was a Titan, meaning she was among the first set of immortals -  Zeus, Hera, Hermes and all the rest are their children. The story goes that Zeus (you may know him as Jupiter) rose up and overthrew the Titans, whose ruler was Cronos (Saturn). And so son defeated father and natural succession arose. But the truth is that the Titans introduced all the natural phenomena without which the cultural inventions of the next generation would have fallen on stony soil.
And Sea begat Nereus, the eldest of his children,
who is true and lies not: and men call him the Old Man because he
is trusty and gentle and does not forget the laws of
righteousness, but thinks just and kindly thoughts. And yet
again he got great Thaumas and proud Phoreys, being mated with
Earth, and fair-cheeked Ceto and Eurybia who has a heart of flint
within her. (Hesiod, Theogony 233  - 39)
And, you know, that may not be the worst name for a plant that is overlooked, but both tough and gorgeous.  Like its Titan namesake, wood aster is unkillable, and sends up spray after spray of starlike flowers (one of Eurybia's children was Asterion), surviving even the most unpromising environment.

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