The best self-seeding plants for a natural garden

Want to embrace a more relaxed way of gardening? Here are my favourite flowers to let run riot...

Cow parsley

Geranium ‘Mrs Kendall Clark’

Dahlias

Cow parsley

Diarmuid Gavin

July 16 2022 08:00 AM

It’s mid-July and gardens are at their peak. There’s a profusion of green in the proverbial 40 shades with every tree and shrub now in full leaf and a rainbow of colour as flowering plants compete with each other to attract the pollinating bees and butterflies to rest awhile on their petals. Some of the spring-flowering herbaceous plants are starting to set seed. For example, the spires of tubular flowers on foxgloves are now starting to ripen. And it’s at this stage that you intervene…or let it all happen.

I’m talking about those plants that freely set seed and, if allowed, their offspring will be found randomly growing in your plot next year. You can halt this process by cutting back the flowers, and this method will encourage the plants to try and flower again and achieve their reproductive mission. It’s up to you which flowers you’d like to see more of and which of the ‘weedier’ ones you’d like to control.

I have a few firm favourites that I let run riot in my garden, and their natural repetition through the area has a unifying effect. It’s a more relaxed approach and one that is gaining in popularity as more and more gardeners turn their backs on weed killers and embrace the natural world.

Here are some of the best self-seeders:

Anthriscus sylvestris ‘Ravenswing’ is a cultivated form of wild cow parsley that you will see in hedgerows across the country billowing with frothy foams of creamy white flowers. ‘Ravenswing’ has dark purple stems and leaves and is pretty easy to identify as a seedling because of this distinctive colour. It has self-seeded in my front garden underneath the birch trees and been useful in extending the season of interest that starts with spring bulbs. It likes well-drained, sandy soil and performs in sun or dappled shade.

Alchemilla mollis is an easy-going perennial with round leaves and sprays of limey-green flowers. It has a great ability to burrow its way in cracks and crevices and between paving stones in a charming fashion. This capacity to grow in very poor, stony soil makes it a good option for those hard-to-plant areas such as dry shade. Always looks delightful after a rainbow as the raindrops sit glistening on the hair leaves.

Foeniculum vulgare or common fennel is dotted around my garden, its elegant tall stems wreathed in fine, frothy, fragrant foliage. At the height of summer, the tall stems are topped by flat heads of yellow flowers. If it threatens to become a weed for you, then cut off these flowers and pop them in a vase.

Digitalis purpurea, our native foxglove, tends to self-seed in clusters, so you get little groups of them standing together. The seedlings are easily identified by the furry leaves in a rosette formation. These are biennials, so you can sow now for next year but also buy some one-year-olds in pots to plant for this year. Tall spikes of wonderful spotted purple tubular flowers which bees love

Geranium palmatum has taken over a good portion of my garden and I’m happy about this as I love the green, ferny foliage and the profusion of pink flowers at this time of year. If you find it getting a bit out of hand, you can easily pull up seedlings by hand and chop off the flowers of bigger plants before they begin to set seed.

Valeriana officinalis is a tall perennial and has been used as a medicinal plant for centuries, most notably as a sleep aid for insomnia. It’s an elegant plant with clusters of pale pink flowers on top of stout stems. It prefers damp conditions in sun or dappled shade.

Echium pininana, or giant viper’s-bugloss, is one of my favourite plants — great for adding drama and excitement as they grow several metres tall. They are biennial, so, for the first year, you will see big rosettes of hair leaves forming, and then, the following year, they send up these enormous spikes covered in violet blue flowers. I can think of no other plant that attracts the same amount of bees.

Other good self-seeders are poppies, Lunaria (honesty), Mexican daisy, borage, verbena, forget-me-nots, aquilegias and Welsh poppies.

Plant of the week

Geranium ‘Mrs Kendall Clark’

Geranium ‘Mrs Kendall Clark’

Hardy geraniums are a staple in many gardens — they’re easy, floriferous and charming, and different varieties are suitable for many situations, from full sun to full shade. It’s hard to single out one of them for additional praise, but ‘Mrs Kendall Clark’ is particularly beautiful. Forming a large bushy plant a couple of feet tall, it is covered right now in the most delicate grey-violet flowers. Wonderful planted among other perennials and roses.

Reader Q&A

I was told petroleum jelly on the stalks of my dahlias would keep earwigs away. Is this true?
Patrick

Dahlias

Yes, this can be a successful means of preventing the earwigs climbing up the stalks. Just get a jar of Vaseline or similar and apply to the base of the stem. You could also try sticky tape to prevent their ascent. They come out at night, so you can also patrol by torchlight and pick them off. In their defence, they are otherwise beneficial insects for the garden, eating aphids and larvae of other undesirables, so best not to kill them if possible, just rehome elsewhere in the garden.

Submit your gardening questions to Diarmuid via his Instagram
@diarmuidgavin using the hashtag #weekendgarden

Diarmuid Gavin: For instant colour, plant some penstemons today and you’ll be enjoying their blooms until the first frost