First, an admission. I have an unabashed love for Euphorbia cyparissias, cypress spurge. It is one of the best looking groundcovers around and it is easy to grow. Cypress spurge has incredibly soft foliage, making it a candidate for sensory gardens. Watch the sap, however, as it can be a skin irritant.
If you search online you will find a fairly even split between retailers enthusiastically selling you on the merits of cypress spurge, especially the cultivar ‘Fens Ruby’, and various DNR’s and conservancy groups warning of cypress spurge’s terribly invasive nature and the dire consequences of letting it loose.
I offer this write-up with a warning: Because cypress spurge can be aggressive, other gardeners are not so happy with it in their gardens, and despite my affection for this particular Euphorbia, I understand and support their outlook. Cypress spurge is considered a noxious weed in some areas, including Colorado, Connecticut, Massachusetts, and Wisconsin, among other places.
Native to Eurasia, cypress spurge is especially rampant in the northeastern United States and Midwest.
I happen to live in a place where Euphorbia cyparissias is not invasive, despite having been introduced to the United States during the 1850’s. As a matter of fact, I’ve only seen it twice any place outside of my own garden: The State Botanical Garden of Georgia, and the Trial Gardens at the University of Georgia.
The first time I saw cypress spurge, it was at the afore-mentioned trial gardens. I asked UGA Professor Allen Armitage about it many years ago and he told me what it was and then casually mentioned they keep mousetraps hidden in the beds to ward off those who might prowl the trial gardens at night.
I didn’t steal any of the Euphorbia, but the Mariana ferns over at the Institute of Ecology were in constant danger of being purloined.
Cypress spurge is easy to grow
As is often the case with invasive exotics, Euphorbia cyparissias is adaptable to a wide range of growing conditions. It can handle direct sun, although we grow it in mostly shade. It is drought-tolerant and likes poor, rocky soils. We grow it in the rich loam common to our garden and it does fine. Perhaps due to the growing conditions in our garden, cypress spurge does not compete well against other perennials, which is one reason I like it.
In our garden cypress spurge fills in the spaces between the coarser perennials without threatening them. Part of the reason it is so despised in other areas of the country is that cypress spurge can overwhelm native communities to the point where a monoculture of Euphorbia cyparissias is established. Simplifying ecosystems is never a good idea, as it is their complexity that helps keep them stable.
I have personally had no problem controlling cypress spurge in the garden. We have a much tougher time with northern sea oats and lamium. I am not putting forth my own experience as some type of evidence Euphorbia cyparissias is not an ecological threat in other areas of the country. What I am offering is simply observational data about the impact of this species in southeastern gardens and landscapes.
Euphorbia cyparissias spreads via rhizomes and it is amazing how tough such a delicate-looking plant can be.
Grown primarily for its foliage, cypress spurge produces small yellow flowers that for me at least are pretty much an afterthought.
Deer and rabbits do not bother this Euphorbia.
There are sterile and non-sterile types of cypress spurge.
I suspect I was sold a sterile version, as I’ve never seen it reseed in our garden. Additionally, according to the USDA Forest Service, most populations in the United States are the sterile version. Cypress spurge is also known as graveyard spurge or graveyard moss because at one time it was planted in cemeteries. The belief is Euphorbia cyparissias escaped cultivation from graveyards and old homesteads late in the 19th century.
What’s the bottom-line? Should we plant cypress spurge in our gardens?
It’s a question that confronts us with many exotic plant species. If you are living in a place where cypress spurge is well-established to the point of becoming naturalized, then the horse has already left the building. Maybe. There are efforts to eradicate cypress spurge. Hawkmoth has been introduced to attack various invasive spurges, including cypress spurge. Still, releasing new exotic species to eradicate other exotic species is potentially environmentally disastrous, even if it is an attempt to make the best of an already bad situation.
We learned about the invasive nature of Euphorbia cyparissias years after introducing it into our own garden. Ignorance is not bliss by the way. I’ve researched the issue and considered removing the Euphorbia cyparissias, but have thus far refrained. At the end of the day, we have over 150 years of data suggesting cypress spurge is not invasive in the southeastern United States.
Whether it is yellow flag iris or horsetail or on and on and on, there is a risk involved with introducing any exotic plant into an ecosystem. It’s not just a case of yes or no, but an opportunity to examine the impact of our actions where we live.
|Common name(s)||cypress spurge, graveyard spurge, graveyard moss, Bonarparte’s crown, yellow weed|
|Of note||research in your area before planting – easy to grow in a wide variety of conditions – one of the most beautiful plants to touch, but don’t get the sap on your skin as it can irritate|
|Water requirements||drought tolerant, average, moist soil conditions|
|Soil quality||rich, well-drained, average, poor|
|Hardiness zone(s)||4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b|
|Deciduous or evergreen||deciduous|
|Exposure||full sun, afternoon shade, filtered light|1 3