cosmos (RHS/PA)
cosmos (RHS/PA)

Keen on cut flowers? Here’s how to grow your own

Garden designer and cut flower aficionado Carien van Boxtel shares her top tips.

Ella Walker
Thursday 08 April 2021 08:00

A bunch of flowers in a jug on your desk, or sunnily arranged in the middle of the dining table, is a sure-fire way to inject brightness into your day. Even more so if said flowers are ones you’ve nurtured and fretted over from seed, and then (with a slight pang as the secateurs got to work) cut and arranged yourself.

Never felt that satisfied, slightly smug joy? It might be time to turn a portion of your plot – or even a pot on a balcony – into a cut flower garden.

This year’s RHS Cut Flower Garden, designed by award-winning Dutch designer Carien van Boxtel, will appear at the RHS Hampton Court Palace Garden Festival (July 5-11), alongside a cut flower garden demo tent, so you can nip in for advice and to ask questions. However, if your inner florist is itching to get going, van Boxtel’s ultimate cut flower tips and tricks are an ideal place to begin…

1. Buy dahlia tubers or sow them

Try any variety with long stems and watch it grow like mad from mid-May. Dahlias are incredibly productive as cut flowers as they regrow in the same season following the principle known as ‘cut-and-come-again’, which means that if you keep on picking flowers, the plant will form new shoots and new flowers, as long as you keep on feeding, staking and watering it well. They are amazingly easy to sow under glass too, especially the single varieties such as ‘Black Jack’ and ‘Bishop of York’.

2. Sow Cosmos from seed

Cosmos should be your number one annual cut flower plant. I have always found it unbelievable that this plant is never grown by the Dutch flower industry, as even my grandmother knew that with only one package of seed you could fill up many vases with ephemeral flowers in summer. They come in the best colours, including antique red, pristine white, lovely soft pinks and burgundies. There are now exciting new yellow and even salmon varieties too! The choice is endless. Easy to grow, under glass or straight in your cut flower bed.

3. Sow annual grasses and amaranth in lots of colours

Grasses and Amaranth are perfect fluffy fillers and will give any bunch of flowers a tremendous lift and airy volume. They are incredibly easy to grow, even straight into the soil. But now (early spring) is the time to sow them under glass. Although a big job as seedlings are tiny, pricking out is very rewarding. Suitable grasses are Panicum capillare or Panicum violaceum (millet), Polypogon monspeliensis (annual beardgrass), Hordeum jubatum (Foxtail Barley), Agrostis nebulosa (cloud grass).

Interesting Amaranth varieties include Amaranthus paniculatus ‘Oeschberg’ in burgundy with curvy floral spires, Amaranthus lividus subsp. lividus, a beautiful dark burgundy fast growing foliage plant, Amaranthus cruentus ‘Hot Biscuits’ or ‘Kuferberg’ in copper and the more compact Amaranthus hypochondriacus ‘Pygmy Torch’.

4. Consider Phacelia tanacetifolia

Not a cut flower per se but it is a beauty of a fast growing and very hardy plant and great for pollinators. I particularly love the fern-like foliage and the powdery blue flowers. They grow incredibly fast after you sow them in raked soil. If you keep on sowing them during the summer you can have beautiful foliage as well as flowers (and bees) in your cut flower garden in spring and summer.

Carien van Boxtel (Rosanna Castrini/RHS/PA)

5. Don’t forget about perennials and herbs

Some of our most beloved garden plants also work well as cut flowers.Some perennials, like herbs, particularly well-established ones, really don’t mind the occasional haircut that much and can be a great addition to a cut flower garden.

Suitable options are Sanguisorbas, Alchemilla, Peonia, Rosemary, Phlox, Aster, Lavendula, Calamintha, and Penstemon. Try and avoid compact varieties: look for longer stems. Perennial grasses like Pennisetum, Molinia and Miscanthus are such beautiful additions to any bunch of dahlias.

6. Roses are worth a punt

Garden roses are not primarily bred for cutting, but in my eyes are far more beautiful, fragrant, wild and romantic than any bunch you can buy in a flower shop. I am particularly fond of the cream and soft pinks of smaller flowered roses like moschata hybrid ‘Easy to Cut’, modern varieties ‘Belgian Lace’, Dentelle de Bruges and antique pink and apricot Meilland rose ‘Acropolis’. Make sure the rose has pretty foliage too, as this will make your arrangement so much better.

Cut Flower garden illustration (Kitty Rice/Minka Prints/PA))

This year’s RHS Hampton Court Palace Garden Festival runs July 5-11. Tickets available now.