Follow Monty Don’s advice for a garden aglow with lime hues of euphorbias

Monty revisits one of his classic books, Gardening at Longmeadow, in an occasional series.

Euphorbias have an astonishing green intensity that adds an electric charge to the garden as they emerge, energising everything – including me – around them.

The first to come into flower at Longmeadow is Euphorbia amygdaloides var. robbiae, which is in the Coppice. 

It has dark, glossy green leaves with brilliant yellow flowers that it will carry into summer. It grows best in light shade and moist soil. 

British gardening expert Monty Don (pictured) gave people advice on nurturing euphorbias and growing radishes in an extract from his classic book Gardening at Longmeadow

The British gardening expert said euphorbia polychroma (pictured) only grows to just over 30cm, making a flat clump of stunningly radiant yellow in any garden

The British gardening expert said euphorbia polychroma (pictured) only grows to just over 30cm, making a flat clump of stunningly radiant yellow in any garden

The variety ‘Purpurea’ has a combination that I love of acid-green flowers and crimson stems and leaves, which gives it real interest for the whole year and not just when the flowers are doing their star turn. 

HOW TO PROTECT LETTUCE 

Monty also recommended growing lettuces 15-23cm apart so they can resist snails

Monty also recommended growing lettuces 15-23cm apart so they can resist snails

  • Slugs and snails love a juicy young lettuce. The best organic defence against them is to grow the seeds in sheltered, slug-free conditions, harden off for at least 10 days and then plant out 15-23cm apart. They then tend to grow strongly enough to resist slugs.
  • Lettuce root aphids attack lettuces later in the season if they have become too dry. The first sign is when the plants visibly wilt and then die. Do not grow lettuces in the same soil for a full year.
  • Downy mildew will turn outer leaves yellow, then pale brown, and the undersides will develop a downy growth. This fungal disease is encouraged by humid conditions, and the solution is to remove affected leaves and thin the batch to increase ventilation.
The gardening expert advised gardeners to grow lettuces in different soils to prevent lettuce root aphids

The gardening expert advised gardeners to grow lettuces in different soils to prevent lettuce root aphids

These euphorbias can get mildew in summer if they become too hot and dry, but a generous mulch around now will do a lot to combat this.

Euphorbia polychroma only grows to just over 30cm, making a flat clump of stunningly radiant yellow. 

However, this display is rather short-lived so needs to be accompanied by something that will take over its role from the end of May. 

I grow it among my ‘West Point’ tulips in the Spring Garden, the two showing off disgracefully for a few weeks before giving up in exhaustion. 

E. palustris is another that grows best in moist soil and also likes some shade. 

We have E. palustris ‘Walenburg’s Glorie’ in the Jewel Garden and in early spring the plants are just producing new growth, which will romp away once they get going and need support if they are not to flop over all their neighbours. 

The foliage turns various shades of orange in autumn, with ‘Walenburg’s Glorie’ notable for its exceptionally brilliant autumnal hues.

In early and mid-spring the best euphorbia for a border in full sun is E. characias. 

There are a number of excellent varieties to choose from – they all share the characteristic black eye to each electric lime-green flower and all have the most shrub-like structure of any hardy euphorbia, so are useful as structural plants within a border. 

We have E. characias subsp. wulfenii ‘John Tomlinson’ in both the Jewel and Walled Gardens, and the flower spikes last from late April right up to the middle of summer. 

In the first year it will produce spires of grey leaves without any flowers. 

This is because although the plant is perennial, the flower spikes are biennial, so they will follow the next spring. 

Once established it will have both kinds simultaneously so you will always have a display. 

Do not worry if it seems to be toppling over under its own weight – it has a tendency to start its growth bowed over but it gradually straightens up to become a long mane, about 1.2m tall, of inverted glaucous leaves topped by flowerheads. 

When the flowering has stopped, the stems should be cut back as near to the ground as possible.

Just one word of warning – all euphorbias produce a milky sap that can cause an allergic reaction to the skin, especially in sunlight. 

So wear gloves when you cut them back and if you do happen to get any sap on your skin, make sure you wash it off immediately.

Monty revealed that the first euphorbias to come into flower at Longmeadow have been Euphorbia amygdaloides var. robbiae (pictured), which are located in his Coppice

Monty revealed that the first euphorbias to come into flower at Longmeadow have been Euphorbia amygdaloides var. robbiae (pictured), which are located in his Coppice

YOUR KITCHEN GARDEN: RADISH

Radishes have been a mainstay of salads for thousands of years. 

These roots were cultivated by the Egyptians 5,000 years ago, and then introduced to Britain by the Romans nearly 2,000 years ago. 

Varieties include ‘Cherry Belle’, ‘Flamboyant’ and ‘French Breakfast’.

Their hot, peppery flavour is popular across all cultures but another reason for their ubiquity is that they are probably the easiest vegetable to grow.

Just sprinkle the seed thinly in a shallow drill (or groove) 1cm deep and they will appear within a week and be ready to harvest a few weeks later. 

Giving advice on growing radishes (above), Monty said amateur gardeners should thin then so they are at least 2.5cm apart and added that fresh radishes can be eaten in early May

Giving advice on growing radishes (above), Monty said amateur gardeners should thin then so they are at least 2.5cm apart and added that fresh radishes can be eaten in early May

It is important to thin them so they are at least 2.5cm apart. 

The thinnings can be eaten – leaves, roots and all – when they are the size of peas, although the perfect size is the circumference of a two-penny piece.

Fresh radishes in early May eaten with salted butter are one of the treats of spring.

They will run to seed in warm or very dry weather so sow as soon as the soil is warm enough in spring and repeat a sowing every two weeks. 

Water regularly – but be aware that too much moisture will produce extra foliage and split roots.