hunting burdock and finding thistle

After a hard week I asked myself what I needed. I’m running out of herbal vinegars, so it makes sense that when nourishing food and something to ground me was at the top of my need list, making burdock root vinegar came to mind – a walk, digging in the dirt and producing great food.

I set off in the sunny morning, hoping to keep ahead of the coming snow storm. I went to my favourite burdock haunt only to find it had all gone to seed and was now spent. Burdock is a biennial, which means it flowers and seeds in the summer/autumn of its second year of growth and then it dies. By that time all the energy and nutrients in the roots are spent. If you want biennial roots you need to harvest them in the autumn of the first year, or the spring of the second year (i.e. before they flower and seed).

I find with biennials that often there is a population of only one year at a time. So there were no first year plants alongside the old seeded ones. I went to a friend’s farm who I knew would know where burdock was if he had any. We walked his place but apart from one or two very small first year plants there was nothing. On to another friend’s place where burdock grows in the driveway. Normally I wouldn’t harvest from a drive with lots of car traffic but in the absence of plants elsewhere I’ll sometimes go with the not ideal. No plants in the drive either.

I wonder if all the rain we’ve had in the last 8 months has made it a poor year for burdock. I’m used to seeing them growing in rocky places so maybe they like well drained soil?

On my burdock search I did pass the milk thistle paddock, full of lush first year plants.

A few words on names of plants: common names are notorious for being used for several plants that have no relation to each other. ‘Milk thistle’ is used for both Silybum Marianum (a thistle) and Sonchus spp (a relative of the lettuce) known in NZ as puha. They are of the same family (Asteraceae), but they are not closely related enough to be used interchangeably as medicine, although there are some similarities. This is why it’s always good to ID food and medicine plants by their Latin name.

In New Zealand ‘milk thistle’ means puha (aka sow thistle or Sonchus spp). In the US to herbalists it means Silybum Marianum. Silybum marianum in NZ is usually called variegated thistle. What I was looking at in the paddock was Silybum marianum, the variegated thistle. Clear as mud!

Silybum is a commonly used plant in herbal medicine. Both traditional use and modern research know it as a potent liver herb. The seeds are generally used for this, but I remembered something about being able to eat the leaf. I dug three plants, roots and all. They came out very easily (all that rain in the soil!), the roots being off white and rather short for the size of the plant. I’ll have to look again later in the year to see what the older plant roots are like.

At home I tasted the plant, being careful to cut the spines from the leaf edge. The leaf is crunchy like lettuce but tougher. Definitely a green taste, bland at first. There is an increasing taste of the bitterness that you would expect in a thistle but not overly so. The stalk, fibrous and juicy, is reputed to be more bitter but I found it more bland than the leaf. I’m sure growing conditions would affect this alot. Bitter is common in liver herbs. It stimulates digestion in the stomach and production of bile.

The root is interesting, not strong but a unique flavour – earthy, a bit reminiscent of burdock but milder, and with an almost peppery undertaste, like a very mild radish. Both leaf and root are definitely palatable.

I could find only two references to silybum edibility. Richard Mabey (UK) said all parts have been eaten traditionally. Tim Low (Australia) says the leaves are still eaten by tribes in Israel and North Africa.

I washed and coarsely chopped the whole plant and filled an agee jar once with the plant and then again with apple cider vinegar. Note the white markings on the leaf, a key to IDing Silybum, that’s the variegated bit.

I wrote on the jar the name of the plant, parts used, menstrum (vinegar in this case), place of harvest and date. I’ll let it sit for at least six weeks and then decant to use the vinegar on salads, greens and grains, or just a tablespoon in a glass of water.

Vinegar is good at extracting minerals and other valuable nutrients so herbal vinegars make a good mineral supplement. I have no idea what the nutrient content of silybum leaf and root is but am usually game to make vinegars from edible plants to see what they are like. I’ll be interested to see what it tastes like.

Here’s a close up, showing an interesting red ring appearing in the root cross section.

Maybe that bigger root would be more peppery than the one I ate.

The next day I check the brew, stirring with a chopstick to get any remaining air out and topping up with more vinegar so the plant is completely covered. It reminds me of globe artichoke vinegar which I make from whole, green artichoke heads. Artichoke makes a fantastically flavoured vinegar and I find it very beneficial to my liver function, producing a definite relaxation in the digestive organs.

Globe artichokes and silybum are fairly closely related. Silybum flower heads can be eaten like artichokes, although I’d guess they’d be more fiddly to prepared. The silybum vinegar smells of the plant now, and I can see the  potential for it being a similar food type ally for the liver.

(Did I mention that burdock is a kind of thistle?)