I had to Google rowan berries and thought...aha, that's what I see regularly. Locally, there are lots of shrub and hedge edged public fields and paths, berries of all sorts abound.
Rowan, rose hip (red and black., blackberry, deadly nightshade, elderberries, blackthorn and more.
Deadly nightshade is a monumental no no of course.
I'm going to try rose hip tea soon, must motivate myself to get going...
It's always worth moseying around to see what's available in the hedgerows.

Rosehip makes a good jelly (together with apple) if you like the flavour. Rosehip is a bit like marmite.
Turned the rowan I picked into a batch of jelly. Basic recipe is as follows:
2lbs rowan berries (destalked)
2lbs apples, washed and cut up as is
10 allspice berries
1 good sized shard of cassia bark (the outer bark of cinnamon, available from chinese supermarkets)
2 pints water.
Put in a pan with a lid and cook gently till the rowan is very soft and the berries are beginning to pop. This will take somewhere between two to three hours as the skins are very tough. Mash the fruit pulp prior to straining.
Put in jelly bag overnight to drip out.
Then either 1lb sugar per pint of juice, or equal weight. The latter is easier if you know the weight of your preserve pan. Make as for any other jelly.