Mention the word “ascot” and you probably think about a silky, men’s tie most likely worn by the upper crust of European society. Then there is the Royal Ascot horse race, where the word is associated with royalty and high society. Today, however, I want you to associate the word with ‘Ascot Rainbow,’ an evergreen, perennial euphorbia that is capturing the imagination of the gardening world.
Botanically speaking, ‘Ascot Rainbow’ is known as “Euphorbia x martinii.” It is native to Australia, where the name “Ascot” is associated with an old, wealthy suburb of Brisbane. In truth, it is known as a spurge, which we most often associate with a host of terrible weeds. ‘Ascot Rainbow,’ however, is worthy of garden royalty.
First, know that the plants are perennial in zones 5 to 9, which means much of the country can enjoy the incredible texture this plant offers the landscape border. They reach 20 inches tall, with an equal spread. I am plant-lusting them now in mixed containers where they have been partnered with other cool-season flowers like pansies, violas, kale and snapdragons. There is just something about the plant that holds my attention.
The foliage is deep green, with golden margins in the cool season. This drop in temperature also fires them up with shades of red, pink and even orange. In spring and summer, the bloom is among the most unique as it features a cup of lime-colored bracts with red centers.
The ‘Ascot Rainbow’ is drought tolerant, and boasts another trait that will thrill gardeners everywhere – they are rabbit and deer resistant. As you would probably think, a drought-tolerant euphorbia from Australia needs good drainage and thrives in full to partial sun.
In a way, I think of them as evergreen perennials, but it helps in design if you consider them more as dwarf shrubs. Plant them in a cluster of three with ornamental grasses and perennials like purple coneflowers, rudbeckias and blue salvias. They fit this type of border, perfectly adding a great deal of interest from both leaf texture and bloom.
If you are the lucky gardener with rocks or a slope, then let ‘Ascot Rainbow’ dazzle all of your visitors as you combine it with other drought-tolerant, tough-as-nails flowers. But as I have stated, you will treasure them as the thriller plant in cool-season mixed containers. They naturally form a rounded ball, and with a layer of pansies, including some trailing in front, they are most picturesque. If your container is large enough, then your options are limitless as you can use them with tall snapdragons, and dianthus and blue-leafed kale, which contrasts with the golden variegation of ‘Ascot Rainbows.’ You are the artist and simply using it will make your neighbors think, “Look who took a special gardening class!”
Maintenance is easy. Remove old bloom stalks all the way to the ground in late summer or fall. Like other spurges, we grow this one not to be eaten, but to be enjoyed for the beauty and texture it offers your garden.
(Norman Winter is the director of the Coastal Georgia Botanical Gardens at the Historic Bamboo Farm in Savannah, Georgia.)
Known as “Euphorbia x martinii,” 'Ascot Rainbow' is native to Australia, where the name “Ascot” is associated with an old, wealthy suburb of Brisbane.Download Image