It is a bit gloomy outside today, but I have some pools of sunshine yellow brightening up the garden. Next month will be all about tasteful pastels, but in May we still crave bright colour.
In all the lanes round here, cow parsley is making a haze of white and it looks wonderful but it is not tame enough to grow in the garden.
For fabulous foliage in the brightest, freshest colours we need to go to another umbellifer which instead of having white flowers is wonderful for spreading pools of bright yellow in the dappled shade of trees. It is called Smyrmium perfoliatum. I know some people resist Latin names but this is a lovely name to roll around the tongue. ‘Smyrmium’ derives from the word myrrh, the Greek word for perfume and if you dig up this plant the roots smell spicy. And indeed it is edible, it has a vaguely celery-like flavour. It is a relation of Smyrmium olusatrum or Alexanders as it is commonly called. The Romans brought this to use as a vegetable and Roman soldiers would carry it on long marches as all parts of it are edible. So presumably where you see it growing alongside the road, Romans have passed by. But it can also be found on sites of medieval monasteries as monks used it as a pot herb. If you are tempted to try it then don’t confuse it with another umbellifer with hollow stems, hemlock, which is deadly poisonous as Socrates would tell you.
Smyrmium perfoliatum is delightful because the leaves are perfoliate which means they wrap round the stems as if a magician is spinning saucers round a pole. And they are such a beautiful colour and then you have the dear little umbels of chartreuse flowers. They look like euphorbias but they don’t have the horrible caustic sap of euphorbias so you don’t need hazmat suits to handle them. Actually, they are not flowers at all, they are bracts, but never mind that, they look like flowers. Flower arrangers love them because they set off whatever is in the vase so beautifully. In the garden they look fabulous with the blue flowers of brunnera or the mauve ones of Erysium ‘Bowles Mauve’. I remember seeing them at Great Dixter growing with the tulip ‘Spring Green’ and edged with forgemenots.
But for a bit of zing, my favourite combination is with the elegant bright red flowers of Tulipa sprengeri. It is not always easy to find this very late- flowering tulip and it is expensive but it sets copious seeds and if you grow these on you need ever be without it. The buds have not quite opened yet, this is one I took last year.
Smyrmium perfoliatum is monocarpic and that means it dies after flowering, but it seeds around exuberantly, some people would say too exuberantly. But I like to have puddles of it under the trees. I can’t see the point of only having one or two plants. And if it shows signs of taking over, you can always find willing takers for any excess plants. Or you can eat it.
After being so rude about euphorbias I do admit to growing some, although not as many as I used to because the sap is really awful if you get it on your skin and dangerous if you get it in your eyes. The colours range from sharp lime green to acid yellow. But those of Euphorbia mellifera are bronzey orange and they smell of honey which I find irresistible. It makes a nice nice large shrub with bright green leaves. It comes from the Canary Islands and Madeira where I have seen huge bushes of it. It doesn’t get so enormous here and it needs a nice sunny spot. Insects love the honey flowers and as you can see the ants are enjoying them.
Euphorbia polychroma is a must have plant at the front of my borders. Oh, hang on, I think it is called Euphorbia epithymoides now, but its common name is the cushion spurge. It is an outstanding plant in April and May with neat cushions of bright yellow flowers. It seeds about, but not excessively.
Other euphorbias in the garden were here when I came and refuse to be evicted. Euphorbia wulfenii crops up everywhere and I weed most of it out. But I like the way it has put itself in front of this old gate post at the end of the drive and it stops passing dogs from using it as a public convenience. A fully grown plant of Euphorbia wulfenii is a lovely sight with large domes of fresh lime green bracts.
Euphorbia robbiae is more invasive because it runs around. But I let a stand of it spread under some trees where it looks good with blue camassias growing through it. The lovely lime green flowers need to be cut off before they turn an ugly brown later in the summer.
Another invasive euphorbia is Euphorbia cyparissias, it makes an attractive groundcover with its little needle-like leaves and dainty yellow flowers, but I would never introduce it, it is far too greedy for space and I am forever pulling it out.
Somehow these shades of lime green, acid yellow and chartreuse seem to fit the season of May when all the foliage is so green and fresh. Soon we will be seeking a more sophisticated palette; once the peonies and roses take over, the garden will look as if it is dressed in velvets, silks and rich brocade and it will be wearing the most sensuous perfume. But for now yellow suits the mood.