Clump-forming Euphorbias for the Border
– zur deutschen Version – Euphorbia may not be top of the wish list for many, but they really deserve a closer look, as they can add great character to a planting scheme. The genus Euphorbia contains a wide spectrum of plants. From the well-known poinsettia used to adorn the house at Christmas, (Euphorbia pulcherrima), to drought-tolerant cactus-like plants, as well as a wide range of useful and decorative hardy garden plants.
They cover a wide range of habitats, from dense shade to full sun, from moist meadows and water margins to dry steppe-like conditions. Some have spreading, invasive root systems, making them useful groundcovers. Some happily self-seed and will scatter themselves in informal planting schemes whilst others are reliable, well-behaved clump-forming perennials.
Two opposites meet in one border
I would like to share two particular contrasting species which we have introduced into the herbaceous borders at the Garden Academy in recent years, that I would not like to be without any more. Their natural habitats could not be more different: one likes it dry and well-drained, the other likes to have its feet wet. Thanks to our long-term commitment to soil care, we have obtained a lovely dark crumbling texture, that is remarkably good at retaining moisture during the hot, dry summer months. As a result, we only water occasionally.
Over the years I have observed that, like people, many plants have a certain degree of tolerance and will put up with wetter/drier/sunnier/shadier conditions – up to a point. Some are more flexible than others, and usually several factors will influence a plant’s well-being. They may, for example, cope with a sunnier position, as long as sufficient moisture is available. Too hot and too dry, may just be too much to cope. There are plants that will cope with considerable frost better when standing in a particularly dry spot than when in a normal bed.
Euphorbia palustris ‘Wahlenburgs Glorie’
This plant is often found thriving in moist meadows or river edges in Europe and across to Asia, as far as north western China. Palustris is the Latin term meaning marshes. Saying that, it seems to be equally happy growing in normal garden conditions.
This early-flowering perennial is a great partner for tulips. It provides a good early volume of light green foliage, topped with luminous yellow-green flowers that provide a fresh contrast to all tulip colours. As the summer draws to an end, the foliage will thin out a little, but finishes the season with a great burst of orange-red autumn colour. It is one of the few perennials that will add some good foliage colour and contrasts well with the warm yellow of Molinia.
Some years ago, I visited a trial of these Euphorbias in Weihenstephan. I particularly liked the cultivar ‘Wahlenburg’s Glorie’. It is strong-growing and can reach up to one meter in height or more. Therefore, I use single plants spread down the border in the second row.
Euphorbia seguieriana ssp. niciciana
This plant originates from dry, stony steppe-like environment in Eastern Europe into Asia. It takes a few years to come into its own, but the wait is well-worth it. I have used it as repeating front-of-border plant, scattered along the margin. Together with Nepeta ‘Walker’s Low’, Stachys monierei ‘Hummelo’ and Sedums it is part of the scarf of planting I like to use to hide small problems such as unsightly dying bulb foliage, holes left by early perennials or brown legs of asters whose lower leaves turn brown before they have even started flowering. They have just come into full flower right now, and look stunning with the inky colour of Salvia nemorosa ‘Caradonna’ and of course our roses. With the neat, narrow foliage, the plants will continue to look good well into late summer/early autumn, which is why I so value them in the front row, where they can reach up to 50cm in height.
I love using Euphorbia for the luminous chartreuse green colour. It is not quite green, it is not yellow and it fits all colours. Dramatic contrasts are achieved in combination with strong colours like pinks, reds or dark purples, subtler harmonies are achieved with whites and yellows. Although the colour effect is similar to that of Ladies Mantle, it has a much longer flowering season.
These plants with strong architectural character and luminous colour are well worth considering to bring a touch of sunlight into the garden on dull days.