Buttercup oxalis / Bermuda buttercup / Sourgrass
(Oxalis pes-caprae)
Edibility
The vibrant, acid flowers work great to relieve thirst when I’m working in the garden. The plant is all edible, and has a refreshing acidic taste. The flowers are very beautiful and tasty in salads, but you can also use the leaves and stems in spreads, soups, pestos… However, buttercup oxalis should not be consumed in large quantities, because if the high content of oxalic acid. The amount of oxalic acid can be reduced with cooking. Although buttercup oxalis is so acidic that it would be quite unlikely to consume it in sufficient amounts to do damage.
Other uses
The bright yellow flowers can also be used to make dye. You just gently heat water with buttercup oxalis flowers until the water turns bright yellow (at least 30min). In this case the oxalic acid is even beneficial as it binds the colour to the wool or silk.
Invasiveness
Buttercup oxalis is an invasive plant that is difficult to control because it propagates with underground bulbs, so instead of bringing the plant into your garden, look for a place that is already full of them.
