Euphorbias are starting to amaze in cool-season plantings whether they be in containers, or as the perfect pansy partner in the landscape. More than likely your first thought is euphorbias for the summer landscape like Diamond Frost but I'm talking Ascot Rainbow that has been the rage since it was declared a Texas Superstar in 2011 and Miner's Merlot debuting this year.
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. Purge the spurge, right? Not so with 'Ascot Rainbow,' and Miner's Merlot.
Ascot Rainbow is considered perennial in zones 5 to 9, and zones 6-9 for Miner's Merlot. While they are classified as perennials, they hate the heat and humidity of the south. So, plan on using them like you would ornamental kale, or cabbage. The difference is that when these euphorbias bloom/ they become an incredible dazzling crescendo to the cool-season landscape. I have babied them through a Georgia summer but it is better to just buy them again in the fall when it's time to plant pansies.
Ascot Rainbow reaches 20-inches tall, with an equal spread. The foliage is deep green, with golden margins in the cool season. A drop, in temperatures, fires them up with shades of red, pink, and even orange. In April and May, the bloom is among the most unique of the garden world 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.
Miner's Merlot is a selection of Euphorbia amygdaloides purpurea. I suppose you should grow it so you can tell your neighbor the botanical name and he would think you were a genius. The foliage as you might guess is a deep dark purple or burgundy. It is so beautiful you would care less that it too sends up a spray of incredible lime-green blooms. It will reach a little taller and wider than Ascot Rainbow.
Since we will be using them as cool-season annual you can be the Monet of the production and rest assured that any way you use them will make it look like you have been to design school. Pansies, snapdragons, dianthus, kale, and cabbage are ideal partners. But so are golden conifers, blue conifers and any other plant you can imagine. These euphorbias are extremely versatile in the cool-season garden.
I treasure them in the landscape and as the thriller plant in cool-season mixed containers. If your container is large enough, then your options are limitless as in the landscape. Like other types of spurge we grow, these are NOT to be eaten, and perhaps handled with gloves, but they are to be enjoyed for the beauty and texture they offer your garden.
(Norman Winter, horticulturist, garden speaker and author of, "Tough-as-Nails Flowers for the South" and "Captivating Combinations: Color and Style in the Garden." Follow him on Facebook @NormanWinterTheGardenGuy.)
(c)2019 Norman Winter
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