|Euphorbia "flowers". Creative commons, Jarek Zok|
Euphorbias come in a wide variety of forms, everything from tiny cacti to poinsettias, but in this article I’m sticking to the perennial varieties that you’ll find in most gardens. And right up front I have to admit to something: I’ve only got experience of one half of the euphorbia world. Because their world is divided, like the Tories or 1920s America, into Wets and Dries. The Dries are the ones you see in gravel gardens or in Mediterranean plantings. The Wets, thanks to heavy clay soil, are the ones I’m more familiar with. The minute I heard of euphorbia palustris (of marshes) I knew I would be planting it. I too wanted green flowers,but without having to buy new ones every spring.
All the eurphorbias I’ve grown are ones that can cope with wet and heavy soil. Euphorbia palustris, the marsh spurge, gets to about three feet high, and flowers in early summer. Like all euphorbias, though, you can just leave the flower heads all summer long. This is because technically they’re not flowers at all but bracts, a specialized sort of leaf that often is decorative in its own right. The actual flower on most euphorbias is tiny, and the bracts may help to guide pollinating insects. I have always been fond of the marsh spurge, and plant it in several places around the garden. It goes well with most colours, and it doesn’t get too big.
For a larger, bolder shape, try euphorbia schillingi, which gets high praise from gardening gurus. It needs a bit of space, because it gets to about four feet high, and tends to splay out from the base. Discreet staking may be needed. The advantage that schillingi has is that it flowers in July and August, later than most of the spurges. Mine always made a fine display next to the monardas, phlox and monkshoods. I just wish I had a picture.
Another good one is oblongata, which is very easy to grow from seed. Sarah Raven’s catalogue says that it is actually a short-lived perennial, but it flowers best in the first year, so she advises treating it like an annual. I haven`t noticed a huge fall-off with my older ones, but Sarah Raven uses her flowers for cutting, so hers probably work harder than mine do. I might add that she recommends euphorbias as greenery in flower arranging, asserting that their yellowy-green colour is flattering to most flowers. The staying power of the flowers/ bracts is an asset as well; once spring is well underway, I have always been able to find some to use with any flowers I had cut or bought.
For the ”hot” section of my garden, I wanted a euphorbia that was more strongly coloured. I found a plant called ‘Fireglow’, a form of euphorbia griffithi, which was tall enough to stand up with heleniums and the grasses, and had lovely orange bracts in spring that fade to dark yellow as the summer wears on. The stems are reddish as well, and the plant has a faint suggestion of poinsettia about it. (Plant one instead of trying to keep your Christmas gift. First, it’ll probably die on you, unless you live in Mexico. Second, in the wild, poinsettias are about six feet high and nine feet wide. The ones in pots are chemically treated with dwarfing compound, and it wears off.) Another plus with ‘Fireglow’ is that is looks fabulous when it’s sprouting; it sends up shoots like asparagus, which are vividly coloured in reddish-orange. It looks great with tulips, too. I had ‘Gavota’, ‘Ballerina’, ‘Abu Hassan’, and good old ‘Queen of Night’ around my two, and if you look to the left of the picture below, you can see a stem of the euphorbia.
|(Picture by Simon Ross)|
Another one that I have grown, but can’t seriously recommend, is euphorbia amygdaloides var. robbiae ‘Purpurea’. (Also known as wood spurge, by the way.) Apart from being able to show off by knowing the name, I haven’t had much joy of this plant. I may have been fooled by the description of it as a shade plant, but the ones I grew under my buddleia (butterfly bush) stayed squatty little things rather than the ground cover I was looking for. They usually come with warnings about how much they spread, and how they sucker, but mine never spread at all. The dark-coloured leaves were pretty, but in the end I junked them in favour of epimediums.
And then there’s the mystery euphorbia. This comes up by the dozens every spring, sometimes quite thickly, and it’s not quite like any of the others. I suspect that it is the bastard child of oblongata and amygdaloides, but who knows. At any rate, it’s a perfectly good euphorbia, with very yellow bracts that are very attractive in the spring, and a reddish tint to the leaves when they`re new. I always leave a few because they’re perfectly good plants, about two feet tall, that don’t get in the way of other things. When they start showing their seedheads in August, everything else has filled in and I can pull them out.
And that’s the funny thing about euphorbias. At first they seem like the dullest plants imaginable, green all over. But they can take hold of you. I`m a mild case, but there are intense ones, like the man in England whose whole allotment is dedicated to euphorbias.(An allotment is a community garden plot, usually dedicated to growing vegetables.) His website is called http://www.euphorbias.co.uk. So don`t write them off too quickly. They have structure, they give colour and interest for months, and they make a wonderful foil for all the richer colours in the garden.
 For a good article on the Dry euphorbias, see here: http://www.guardian.co.uk/lifeandstyle/2011/jan/22/gardens-euphorbia