The constant battle of keeping weeds at bay

“One year’s seeds means seven years of weeds.” The old saying is worth bearing in mind if you are plagued with them throughout the growing season.

Tuesday, 11th June 2019, 10:30 am
Euphorbia Robbiae is invasive. Picture by Tom Pattinson.

The simple expedient of removing weeds before flowers and seeds form can minimise future damage and give your cultivated plants a fighting chance.

If only the seeds we buy in packets would germinate and grow as readily as chickweed and groundsel.

They’re both annual ephemerals with relatively shallow root systems so hand-weeding or running the hoe through them on a hot, sunny day will see them off quickly.

However, that’s not the end of it. There will be more of the same in the soil they sprang from and within a week or so they’ll emerge for a repeat performance. These two common weeds can go from germination to mature seed-bearing within six weeks.

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In the process they not only compete for soil nutrients and growing space, but also play host to several plant pests. For this reason alone, it’s important to keep the land clear of them, even in winter.

Cultivating vegetables and some soft fruits in rows makes regular weeding a little easier, especially when the main offenders are annuals. Even summer bedding displays are manageable with regular hand-weeding, especially when initial planting has been close to deny any weed access.

The main headache in this fellow’s garden comes from the mixed ornamental borders. Where ground-covering plants, such as heathers are planted, weeds can’t gain a foothold, but the diversity of shrubs, herbaceous perennials, bulbs and annuals offers too much cover for the deeper-rooted perennial weeds.

Lost in the dense foliage, they’re often well-developed before we notice them. Even then, pulling-up couch grass and ground elder is not an option – do so and the perennial root section left behind quickly regenerates.

Nor is applying a contact herbicide the answer, not just because it goes against the grain and is fatal for any ornamental plant foliage it touches, it’s simply not effective enough on these two weeds.

Digging them out systematically, leaving no smaller pieces behind, works for me. When a group of doronicum was noted to be hosting ground elder last summer, we played a waiting game until autumn, then they were all dug out and laid on a hessian sheet, where roots could be teased apart.

Other herbaceous perennials lifted for this purpose, in their dormancy, suffer no ill effect when replanted, watered and made firm immediately afterwards.

This method is labour-intensive, but life could be worse. Thank goodness there’s no mare’s tail to dig out. Those roots go much deeper into the soil.

It remains common practice to treat perennial weeds on spare land or pathways with a herbicide, but the ongoing debate about the safety of chemicals such as glyphosate has some gardeners trying alternative control methods. For example, laying a tough membrane and covering it with gravel or bark mulch.