HEAVY rain followed by lots of sunshine has flipped the garden into summer mode. The hot border is filling up with colour and the rose arch is really starting to zing with the blooms of Rosa American Pillar.

But along with the flowers come the weeds and we are hard at work weeding across the garden, as well as getting in the last of the annuals and the dahlias.

As I was having a good weed down at the bottom of the hot border yesterday, making a place for dahlias to be planted, it got me thinking about how we define a weed.

One definition is a weed is a flower in the wrong place.

Another definition is that a weed is a plant that can grow, flower and set seed (often thousands at one flowering) more than once in a year, often in inhospitable locations.

Moreover, such seed can survive a long time and germinate at the slightest hint of cultivation.

So something that looks gorgeous anywhere like Echium vulgare (viper’s bugloss) currently flowering in our annual meadow is definitely a wildflower, but Stellaria media (chickweed), a single plant of which can generate 70,0000 seeds in one go, is a weed.

That led me on to thinking that surely plants that are so efficient in what they do must have some sort of purpose other than just being irritating to us.

The ubiquitous chickweed is reputed to have medicinal purposes, used for everything from coughs to constipation.

It was also one of the weeds that quickly colonised bomb sites along with willow herb (Chamerion angustifolium) in London and other cities after the Blitz.

Its leaves can be added to salad and it is a tasty meal for hens, hence its common name.

Ragwort is another interesting example. It is the most common cause of poisoning in farm animals and horses.

It is also a food plant for more than 40 species of insect, including 29 for which it is the only food source.

What is also interesting is that most animals will avoid it while it is growing, but can’t differentiate it once cut down and will eat it dry in hay or wilted and dry after being sprayed with herbicide (it is as poisonous dead as alive).

Even my two pet hates cleavers (Galium aparine) and ground elder (Aegopodium podagraria) have their purpose.

Cleavers has always been said to be good for the treatment of bad cuts and burns and modern clinical trials have borne this out.

It is also apparently good to eat as a wilted green. Ground elder was said by the Romans to cure gout and it is edible, having a lemony taste.

So even weeds which we might see as a nuisance or even a threat have their purpose.

Whether it has a medicinal purpose, is food for us or other species or it just looks lovely; even the most irritating are good for something other than annoying us.

Food for thought.