I’ve been doing some weeding. This is in our British garden where the weeds are always jumping at this time of year, especially when it’s been so wet and it’s been unwise to get on the soil.

I’ve also been having a clear out, bringing files and folders out from the back of the file cabinets and what did I find? My weed collection, three fat folders of pressed plants, that I made when I was a student at the Royal Botanic Gardens at Kew in London almost forty years ago (below right, click to enlarge).

And the first pressed plant I found in the first folder I opened was the same plant I’d just been pulling out of the garden: hairy bitter cress (Cardamine hirsuta). We have a close relative, Pennsylvania bitter cress (Cardamine pennsylvanica) in our American garden.

And this brings me to my first rule of weeding: our top weeding priority should always be to pull out are the weeds that are in flower or developing seeds. Hairy bitter cress rarely grows more then 10in/25cm high but can still can produce 700 seeds and fling them 31in/80cm, but it can also produce seeds when just two inches (5cm) high. So pull it out. Now.

Many of the traditional rules of gardening have little value but “One year’s seeding makes ten years weeding” really is true. Dandelions (below), which as annoying in Pennsylvania as they are in Northamptonshire, can produce over two hundred seeds in one seed head. So - obviously - don’t let them seed.

My second rule of weeding is always to shake the soil off the roots after you pull out the weeds and before they go on the compost heap or (in those cities with green waste recycling) in the green waste bin. You can ship out a huge amount of good soil if you’re not careful.

And my third rule of weeding is this: get them when they’re young. When nasty perennial weeds like bindweed come through at this time of year, a one inch shoot is often an indicator of yards of root underneath. Later, when their twirling stems become entwined with our garden plants, it’s all but impossible to remove them. It’s so much easier when they’re just an inch high and, at this time of year, if you disturb the plants you’re trying to protect when extracting bindweed roots they’ll soon settle down again. By the time the bindweed is strangling your cistus (top) it’s far far FAR too late.

My final rule is this: Don't spend half a day weeding and then the rest of the week nursing your aching back. I did half an hour this morning and half an hour this afternoon and I’ll try to keep that up. But if I’d spent two hours forking out weeds at a single stretch this morning (as I was tempted to do) I’d not be able to get out there again tomorrow or the next day or the rest of the week. Little and often…

OK, it's time to get back to the bindweed and dandelions and the dreaded hairy bitter cress.