I’m currently reacquainting myself with stinging nettle. For many years I made nettle leaf infusions, and then my body and tastes changed and I haven’t used it for a long time. Now with the wet spring there are nettles everywhere I go, so it’s hard not to be thinking about medicine again. I’ll do some posts about nettle as food and medicine, but first I want to talk about the plants themselves.
We have a handful of nettle species here in NZ, most are native and several are introduced.
Urtica ferox, ongaonga, tree nettle: endemic (grows only in NZ).
Urtica incisa, dwarf bush nettle, scrub nettle: non-endemic (grows in Australia too).
Urtica linearifolia, swamp nettle: endemic.
Urtica aspera, grows in the South Island: endemic, rare.
Urtica australis (aka U aucklandica) ongaonga/okaoka, onga, taraongaonga, taraonga (I’m guessing the number of Maori names is due to the mix of Northern, Southern and Chatham Island dialects), Southern nettle: endemic, rare, found in coastal Fiordland, Stewart Island, the Chathams and the sub-Antarctics. Originally grew as far north as the bottom of the North Island (probably).
Urtica urens, stinging nettle, small nettle, nettle: common throughout most of NZ, but uncommon in places (West Coast, Fordland, Taranaki, North Auckland).
Urtica dioica and subsp gracilis, stinging nettle, perennial nettle, tall nettle: uncommon.
Urtica membranacea, a Mediterranean nettle: I’ve not seen it but it’s listed as naturalised in Canterbury at least.
I’m going to write about the most common species. Nettles are plants of the disturbed ground. They grow in places where the soil has been bared, and so are common along roadsides, tracks and where land is overgrazed or otherwise cleared. Nettles love nitrogen and grow in places where the nitrogen is very high eg animal manure. I suspect that nettles play a crucial role in breaking down animal manure in places where the soil is marginal and struggling to re-establish other plants.
Nettles are most notable to the general public for the hairs on leaves and stalks that sting, sometimes quite painfully. Nettles are good medicine and food (being very dense in nutrients), and are useful in the garden and for fibre. As such they are another important plant to know well in preparing for the powerdown/post peak oil future.
Urtica urens is our most common weed nettle and was introduced in the 1800s, most likely from the UK (first recorded in NZ in 1860). It’s an annual, grows in disturbed soils, and seems to especially like sheep shit. I find it most often under and around stands of trees that sheep like to shelter under (manuka, kanuka, pine etc) but it will also sometimes grow in the open where the rabbits have been digging or where the soil has been disturbed in another way. My ex-neighbour always had a great crop of annual nettles in her garden because of the chicken manure and digging. Unlike some of the other nettles, urens has an affinity for dry ground.
Urens will often grow on a single stalk, but it can also grow multiple stalks and fan out into a small bush. It is a darker green than the other nettles (getting darker as it ages) and has a more rounded and textured leaf than the perennial. It’s sting is less painful than the perennial nettle but it has more stings and on both sides of the leaf (as well as the stalk). Most of the references you see to nettle as a medicine and food are not to this plant (more on that in a later post). They’re to its sister the perennial nettle:
Urtica dioica, a perennial nettle, was also introduced in the 1800s. It’s uncommon enough in NZ that I’ve never seen it growing wild, despite looking hard. In the US people talk about it growing near water. It has a pointier leaf than the annual nettle and looks similar to lemon balm in shape.
Unlike the annual, the stings on the perennial are predominantly on the top of the leaf, which is why some daring folk will eat them raw.
It’s considered a pest plant in NZ (what used to be called a noxious weed), mainly because its strong, spreading root structure can be difficult to contain once established. In some parts of NZ it’s illegal to distribute any part of this plant, so be careful, eh? If you want to grow it best to plant it somewhere reasonably contained like you would mint.
Urtica ferox, aka ongaonga/tree nettle, is one staunch plant. This native is large – up to several metres high, and grows in the bush, especially along margins of river and roads or in clearings. It also grows on farm land, having that same affinity for sheep shit and cleared land, but unlike the annual nettle (Urens) it often grows well out in the open.
The sting of this native is so strong that bad enough exposure can kill horses (eg where horses have been ridden through a stand of ongaonga. Humans too, but that’s incredibly rare. The sting is much worse than ordinary stinging nettle, and contact from even a single hair can be very painful for hours.
Urtica incisa and Urtica australis both have the potential to be useful as medicine if cultivated or reintroduced into native or non-native ecosystems and gardens. The seed of both those native nettles is available on Trade Me if you want to try them out, and the plants are available from Oratia Native Plant Nursery (as well as ongaonga).
Incisa I’ve seen in the bush and it’s always quite small so I’ve chosen not to harvest it (better to leave it for the bush anyway), but it would probably grow bigger in a garden (descriptions of the plant in Australia are much bigger than the ones here). I always see it growing near creeks so it’s one of the wet footed nettles.
The Chatham Island nettle (U australis) in particular looks interesting with its large heart shaped leaves (one report says they’ll grow as large as a lunch plate). It’s a perennial which means you can harvest the plant and it will regrow another crop. I don’t know how bad its sting is but online sources suggest its milder than most nettles.
All the nettles are becoming popular in NZ gardens because nettle is a prime food for the caterpillar of the Monarch and Red Admiral/kahukura butterflies.