Silverweed is a cool temperate root crop (hardy zones 4-8 ) that may have been harvested for human food since the last ice age ref. It still is sold in markets in Tibet and Nepal, although little cultivated now in areas of the world where the potato has taken it's place as a staple crop. Officially the species name is Argentina, but most references will still refer to it as Potentilla (there is some naming confusion too see eat the weeds ). In Europe the main species is Potentilla anserina. In North America both P. anserina and P. anserina spp Pacifica (pacific silverweed) were cultivated and eaten as a staple carbohydrate for many peoples of the PNW. Coastal gardens were created and cultivated to increase the area suitable for silverweed, springbank clover and rice root fritillary to grow. Although silverweed prefers a damp soil, it will persist in quite rocky areas.
Silverweed is a perennial plant that spreads by runners over the surface which put down roots at nodes every few inches. The fern like divided leaves are silver coloured undeneath and may be silvery on the top side as well. The plant has buttercup like golden flowers. The silver and gold colours giving it the name 'richette' in French. It is also called goosefoot (anserina is latin for goose) possibly because geese like to eat it, or someone thought the leaves look like the feet of geese.
Silverweed in Scotland
The nodes send down 1 to 4 storage roots which are up to 30cm or so long and may have thickened sections. If the plant is left to regrow these are replaced with fresh roots the following summer. The roots are rich in carbohydrates, having more starch in than potatoes per unit weight. They also have some protein (being complementary to barley), minerals and vitamins. From eattheweeds.com:
Per 100 grams of steamed roots it has: 132 calories, 3.1 grams of protein, 0.6 grams of fat, 29.5 grams of carbohydrates, 9.5 grams of fiber. ....... The B vitamins are B1(thiamin) 0.01, B2 (riboflavin) 0.01 and B3 (niacin) 2.4 mg. The minerals line up: Phosphorus 109 mg, sodium 65 mg, magnesium 60 mg, calcium 37 mg, iron 3.5 mg, zinc and copper 1.1 mg each, and manganese 0.8 mg.
Many online sources describe the roots of pacific silverweed as bitter and that the roots are steamed or boiled to make them more palatable. It may be that this bitterness is varable with growing conditions and harvest period ref, or possibly be associated with genetic differences in the plants themselves.
thickened storage roots
This video for children shows how to identify silverweed and how it grows near the beach in North America (skip the first half)
In Scotland silverweed was eaten too, especially in the highlands and islands where is has been described as 'the seventh bread of the Gael' and 'spring carrot' ref and appears to be generally less bitter. The gaeilc for silverweed is brisgean referring to the brittleness of the roots. The roots were dried for later use and used in stews or as a flour substitute.
All parts of the plant appear to be edible, although the leaves less often mentioned as a food source. The plant is also used medicinally pfaf stating "The whole plant is antispasmodic, mildly astringent, diuretic, foot care, haemostatic, odontalgic and tonic". Mentions are also made of placing the leaves in shoes to prevent blisters.
Let's share our experiences of planting, growing, and using silverweed!
I've been interested in silverweed since I realised it used to be a staple crop round here. It actually grows quite happily in grassland, although doesn't appreciate being closely grazed, or maybe it is previous ploughing that knocked it back. A few years ago I went to the trouble of collecting some different plants from round the island to try and get a breeding population, since I'm not sure whether it is self fertile. I've tried eating them before and found them quite tasty - like hazelnuts when raw, and like baked potatoes when cooked. The only time I found them bitter (which many of the ethnobotany reports mention) is when we harvested them in September before the foliage had fully died back see my neolithic menu thread.
silverweed growing in long grass on Skye
So I had a lot of silverweed creep into my simple farming area last year - It was in the roots bed as that had failed, and it was happily cohabiting with the potatoes this year. Since I was digging the bed pretty thoroughly to get the potatoes out I thought I'd see what the silverweed harvest was like. So this is from a 10 foot row of my 'Skye blue' potatoes.
silverweed v potatoes
The potato yield wasn't great; just over 6lb from the row. I suspect I have a virus as these tubers have been saved locally for several years. One or two tubers weren't as good as they looked as there was a little slug damage, but not too bad. The silver weed as pictured was about 2 1/2 pounds. No noticeable pest damage to the silverweed roots at all.
So I sorted the silverweed into multi rooted plants and single rooted plants (plus broken bits). I'm assuming now that the multirooted plants were ones that regrew from last year and the single rooted plants were ones that grew from this year's offsets. There was 4Oz of broken bits, 15 Oz of single root plants and 1lb 2Oz of multiroot plants. The multiroot plants often had the shrivelled remains of last year's storage root which I removed.
sorted silverweed roots
I selected some of the nicest looking roots for replanting in my polycultures area. I'm not really sure what characteristic will be most useful - thicker roots (which tend to be shorter) or long straight roots (which are maybe easier to clean, but often break off) so I selected some of both. The longest unbroken root was about 18 inch long and the fattest roots were generally about 8mm diameter.
selected silverweed roots for replanting
The rest of the roots I cleaned by rubbing them in cold water between my fingers. This was slow and I wonder if there is a quicker way. You could probably get almost all the mud off by rinsing with some sand in the water, but I tried to get most of the skin and little hair roots off, as I think this is where some of the bitterness comes from, plus I prefer the white clean look of the roots! When clean and trimmed of the remains of the growing points I had about 1lb 8Oz of good roots. About half I dried in the lower oven to preserve for future experiments with dried roots, and about half I boiled for a few minutes to try cooking with those. I'm thinking - something like rosti, oatsilverweedcakes, leavened griddle cakes, maybe cheesy scones....
boiled silverweed roots
I tried drinking the water from the boiled roots, and it tasted like carrots, but without the sweetness. It might be nutritious, but not very pleasant!
dried silverweed roots
So watch this space - hopefully some more silverweed adventures to come!
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