Euphorbia canariensis can grow in a tough, rocky environment

Peter Dowdall wonders at the ubiquity and range of a hardy perennial whose sap can cause a severe rash.

Many of the summer flowering perennials will benefit from being tidied up now and having spent flower stems removed, or else you will end up with a bedraggled looking garden.

Delphiniums, Lupins, Leucanthemums will all have produced many flowers by now and should have the first of their flowers, which have now gone over, removed. 

The heavy showers which the gardens have endured over the last few weeks will also have taken their toll, particularly on flower stems which were not staked and many will now be lying on their side or at best growing at precarious angles. 

Again, reducing the length of these stems will help in tidying up the appearance of the plant.

Euphorbia is one such perennial and its evergreen varieties such as Silver Swan and Purpurea are two particular favourites of mine producing lush, fresh flower stems from early spring. 

Euphorbia wulfenii: Responds well to sunlight and can withstand periods of drought.
Euphorbia wulfenii: Responds well to sunlight and can withstand periods of drought.

Emerging from within, the fresh foliage stems these blooms produce, though simple in make-up, are stunning.

However, emerging from tired and older foliage stems these blooms do not have anything like the same visual effect, rather the shrub looks forlorn, leggy and all over the place.

Cut back now to see more displays this summer. 

Flower stems which are finished should be removed, but also stems of foliage which have become too lanky and untidy need to get the chop. 

Don’t fret about being brutal, as the Euphorbias will thank you and repay rich dividend with new growth nearly immediately, and the plant will look once more at its best.

However, do be careful of the milky latex- type sap which will ooze from the stems when pruned. 

This is a nasty irritant to eyes and mouths and can lead to long-term and serious damage. 

Indeed, for many, contact with the skin can lead to blistering and the development of painful rashes, so do be careful, wear gloves, avoid contact with the face and in particular the eyes, and also keep small children and family pets away.

Euphorbia ‘Fireglow’ is one of the better-known varieties in our gardens and it produces dramatic orange-coloured stems up to 1.2m tall. 

It’s herbaceous, and as such, pruning isn’t as important as any of the untidy growth will be gone by the time the harshest of the winter gets to it and each spring new growth comes once more from ground level.

It’s vigorous though, and even during one growing season an established clump will cover a large area and thus a pruning now will also keep it in check. 

Technically, the actual flowers of Euphorbia are quite nondescript but produced as they are, with coloured bracts beneath and in long stems, they create a rich lush effect in the garden, the perfect accompaniment to some of the other more showy flowers in the summer garden.

They are used primarily for their foliage effect and as their flowers are more subtle, they are therefore an excellent plant to use among the more colourful and flowery plants as they will provide more constant interest and also a depth that flowers on their own cannot achieve.

Silver Swan and Tasmanian Tiger are two beautiful varieties with grey-green foliage edged with a creamy margin. 

I prefer Silver Swan as it is a brighter and whiter looking plant and ‘cools down’ whatever you plant it with.

I have used it in a much more subtle combination — not to contrast but rather to work with other plants to create the same effect. 

It is growing with the graceful bluey-grey ornamental grass, Heliotrochon sempervirens along with Convolvulus cneorum with its beautiful silver foliage and white flowers. 

I have the white Hydrangea, ‘Polar Bear’, in the background and the whole combination is underplanted with the simple foliage of Euonymus Silver Carpet.

The overall effect of this planting is calm and cool and is as much about the contrasting textures as it is a good example of using similar colours to create a relaxing planting scheme. 

Euphorbia pulcherrima from the Latin ‘pulcherrimus’ meaning beautiful, is another one of my favourites. In fact, this plant is grown for at least a month in nearly every single Irish home. 

Grown indoors and more widely known as poinsettia this is of course, grown as a houseplant during the Christmas season and it is this species which illustrates just how colourful the bracts of the Euphorbia can be.

Hard to believe the garden Euphorbias I referred to are members of the same genus as the poinsettia. 

This gives an idea of just how big the Euphorbia genus is and the mind boggles if you have a look at the Cathedral Cactus, the common name for Euphorbia trigona.


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