Thursday, July 16, 2009

Wood sorrel (Oxalis incarnata)

Wood sorrel grows around borders and up against rises and mounds.

Raw, the leaves and stalks have a bright, sour taste. You can use them in both sweet and savoury dishes.

Wood sorrel - savoury uses
The leaves and flowers are nice tossed in a green salad, and the flowers make a good edible garnish.

Wood sorrel goes well with root veges, fish, and chicken. It's yummy with cream. I love chopping up a big handful of leaves, stalks, and flowers and having it in a potato salad with a cream dressing.

We also had a delicious wood sorrel, kumara and potato gratin last week: two handfuls of chopped wood sorrel layered with pre-boiled, sliced potato and kumara, and cream poured over the top ... baked at 180 degrees C, until it was starting to brown.

Wood sorrel is tasty on its own, but also delicious with two other herbs that you can forage for at the moment - onionweed and wild parsley.

Wood sorrel - sweet uses
For desserts, try adding wood sorrel to apple, peach or pear pie. I'm keen to make a wood sorrel jelly, and will post the results when I do.

If you want to experiment with wood sorrel, a good starting point is to find a way to use it in a recipe in place of lemon.

Wood sorrel as medicine
I don't think wood sorrel is used heavily as a medicinal herb these days, but it does have some traditional uses: to cool and lower fevers, to restore appetite, and as a gargle for mouth ulcers.

For more on its traditional uses, try the historical classic - now online - Mrs Grieve's Modern Herbal. I'm keen to try making that conserve with orange peel!

Wood sorrel as a curdling agent
Because of wood sorrel's high acid content, you can use it in some simple cheese recipes in place of lemon, adding it to milk to separate the curds and whey. I haven't managed to find the right technique to do this properly yet. If anyone has - I'd love to hear!

Wood sorrel's place in the world
Wood sorrel is an Oxalis. Other small Oxalis plants are eaten around the world, too. In his native edible plants book Andrew Crowe has an entry on the Bermuda buttercup, which is an Oxalis about the same size as wood sorrel, and similar looking, but with slightly narrower, darker heart-shaped leaves, and a yellow flower. I've seen a wee bit of it round Wellington but not as much as wood sorrel.

Sorrel just means 'sour' or 'sour plant'. The two main plant groups referred to as sorrels are those in the Oxalis genus (like wood sorrel and Bermuda buttercups), and those in the Rumex genus.

Garden sorrel and French sorrel (which look large and lettucey, and are cultivated as garden plants) are both species of Rumex.

The Oxalis and Rumex genuses are not really related to each other.

Because of wood sorrel's high oxalic acid levels you don't want to eat too much, but general consensus seems to be that in small amounts, it's fine. (Unless you have gout, kidney troubles or rheumatoid arthritis and are avoiding all high-oxalic-acid foods - which also include spinach, rhubarb and more ...)

Wood sorrel links:
Wood sorrel/onion weed butter with fish

Wood sorrel in Gwen Skinner's NZ foraging classic on googlebooks

Plants for a Future database

Google Images


Heather said...

Hi Johanna,

I heard your piece on National Radio and had a thought about your cheese-making dilemna. Have you tried chopping the oxalis and then putting it in a muslin bag, and adding it like that to the milk? The acid should still get into the milk, but separation will be easier. We do this with cores/skins/pips etc. when making jellies and marmelade. If you don't have a muslin bag, you can improvise with a men's hanky tied with string, or you can buy muslin really cheaply from Spotlight etc.

I've only used oxalis in soups and salads so far (and for nibbling on), but your apple pies sound great and I'm definitely making some soon! We have a bay and an ornamental banana in pots and they always have a good crop of oxalis underneath them (the yellow kind, mostly), which from time to time I have to prevent helpful people from weeding for me!

I actually discovered oxalis as a very young child when I spontaneously ate some (as kids do...) and thought it was really yummy. Then my parents discovered me, didn't know it was edible, and scared me off. Many years later in Switzerland my flatmate introduced me to 'Waldklee' (literally 'forest clover') when we were out walking. I put it in my mouth and instantly recognised it as familiar, although it was a while before I placed it as the 'poisonous' weed I'd enjoyed as a preschooler!

Johanna Knox said...

Hi Heather - the muslin bag idea is brilliant! I will absolutely try that. Thank you.

'Forest clover' is a nice name for it ...

AJB said...

Hi Johanna,

The Oxalis in your picture (which is commonly found in NZ) is the South African Ox. incarnata. As far as I know Ox. acetosella isn't in NZ.

Still growing CPs? :)


Johanna Knox said...

Hi Andrew - thanks for this important correction!!

How are things with you? We've had a few upheavals over the past year and haven't managed to keep more than a couple of CPs alive. :( I hope to get some more soon.

One of your pinguicula had a baby a couple of years ago! Both grew really well for a while, but sadly we lost them both at the start of this year due I'm sorry to say to my neglect.

I have also been meaning to join the group that the guy in Nelson started. Is it very active?

Best wishes