Woodsorrels have Shamrock leaves
Oxalis species have trifoliate leaves
Not to be confused with Sorrels which are in the Dock family.
Creeping wood-sorrel Oxalis corniculata
This Oxalis is also known as Procumbent yellow-sorrel and is the smallest-flowered woodsorrel I’ve seen. It grows on my patio underneath my dining room doors. The small trifoliate leaves are approx 3cm across and have a purple tinge. In my garden it grows in gravel in full sun and flowers all summer. It is a low plant up to about 10cm high and creeping (unlike Oxalis stricta which is upright).
You can see from the flower pics that the flowering stems hold 2 – 3 flowers (unlike Oxalis exilis which only has one).
The small yellow flowers are about 1cm across with five petals and ten stamens.
Wood-sorrel – Oxalis acetosella
I found this lovely little plant – or rather hubby Mike did – in woodland in West Sussex among Beech trees. The larger white flower was fully open in April and the whole plant was only a few cm off the ground. The green trifoliate leaves looked as if they were drooping and were larger than the yellow sorrel above. The flowers were about 2 to 3cm across, only one per stem. Each flower was nodding while in bud and had five fat white petals with lavender veins, five yellow marks near the centre, and ten white stamens.
You can see that the little wildflower is growing near the base of a tree.
Pink-sorrel – Oxalis articulata
This introduced species is now found commonly in the wild. We have it in Seaford and I see it sometimes on my health walk near the cemetery. The one in the picture was growing in long grass at Rye Harbour nature reserve. It was in full flower in May when I visited. The small candy pink flowers are about 2cm held in umbels on stems about 15 to 20cm high.