Driving around southern England visiting family and friends over the recent holidays, we’ve seen some intriguing plants growing alongside the motorways.

The most surprising, perhaps, were mature apple trees, well laden with ripe fruit. Two trees with bright yellow apples were spotted growing by the side of the A303 (one of the main routes from London towards the south west of England). There were just one or two green apples on the half dozen trees I spotted last year by the M25 (the huge ring road around London). And on the A14 in Cambridgeshire I noticed three trees in fruit – and only here was it possible to stop and take a closer look at one of them.

The A14, by the way, has an interesting history. It connects England’s two main north-south routes, the A1 and the M1, from east to west and it was first built to enhance the effectiveness of the nuclear deterrent. The American Air Force had a batch of nuclear-armed cruise missiles housed at RAF Molesworth, an air force base without a decent road that could accommodate their mobile launchers for twenty miles. So this major new road was built to allow the missiles out into the wider world. It was opened in the 1980s, but RAF Molesworth is now largely an intelligence gathering site. Bob Hope entertained at the base in 1943 and the base has the unique distinction of more of its American servicemen marrying English women than servicemen from any other American base in England.

Anyway, those apples… I also managed to pick a fruit safely. After scrubbing it well I found that it tastes rather like a soft and squidgy ‘Cox’s Orange Pippin’ (Britain’s favourite apple). A friend, having also tasted a slice, suggests it would be ideal for an apple fool.

The question is, where did these trees come from? Some, I’m sure, are the result of travellers struck in traffic munching an apple, eating their picnic before they got to the seaside, and wearily throwing the core out of the window. The trees on the M25 are sited at a stretch notorious for jams. But in recent years many trees have been planted alongside new and improved roads when construction is complete and these are mainly native species. So it has also been suggested that unscrupulous nurseries may have supplied surplus stock of culinary or fruiting apples instead of wild crab apples.

Either way, they're intriguing additions to our roadside flora.