There are many truisms in gardening but “one year of seeds equals seven years of weeds” is resonating louder than most at present. On cultivated land and out in the countryside, plants that do not know when to stop colonising are shaping up to grab as much growing space as possible.
Sometimes the very plants we buy and love develop invasive tendencies and we have to take action. Aquilegia, foxglove, borage, welsh poppy, viola and oregano keep trying to overrun this garden, seedlings popping up where they’re not wanted. Such occasions demand resolve and a firm hand on the hoe.
Annual weeds such as groundsel and chickweed may appear innocuous, but don’t let familiarity breed contempt. Running the hoe through them on a hot sunny day, raking together and removing the debris, should only be seen as a stopgap measure. A new generation will emerge from seeds already in the soil, germinate and grow to maturity in a matter of weeks. This continues not only throughout the growing season, but all year round.
Clearly, it would make sense to grub out all weeds before they flower, let alone set seed, and in doing so break the so-called seven-year cycle. But life’s not as simple as that. Some seeds can remain dormant in the soil for decades then spring to life when conditions are suitable.
Controlling perennial weeds is a constant battle of wits. You can remove the top growth and prevent seed formation, but some of the root systems either go deep into the ground or send rhizomatous growth in all directions. Miss the smallest piece of ground elder or dandelion root and it will regenerate immediately.
Nor does reaching for herbicides necessarily solve the problem. Once perennial weeds infiltrate the root system of herbaceous perennials in a border, as ground elder did in a section of mine last year, there is only one option. Wait until the dormancy period, lift the plants one at a time, separate the roots on a sheet of thick polythene and pick out every last piece of the invader — then re-plant. This year the follow-up has been critical. I have monitored that section, digging out any of the weed that persists.
How such troublesome plants appear in the garden is interesting. It pays to examine anything from outside, just as a precaution. The potted shrub or border perennial bought at a charity plant stall could well be a Trojan horse carrying invading weed seeds. Bird activity is another channel, seeds attached to the feet by mud or passed through the digestive system and deposited in your garden with manure. That’s how the young brambles keep springing up.