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Apios americana or Hopniss heaven

Apios americana, Groundnut or Hopniss

I’ve been growing Apios Americana for a few years now. Native to North America, it’s a leguminous plant that has everything going for it –  delicious tubers, beautiful ornamental vines with scented flowers and is nitrogen fixing too. Also known as Groundnut and Hopniss (from the Lenape word “Hobbenis”) it was an important staple food for many indigenous peoples in North America. I’m so excited to be working with this perennial edible plant that has so much potential as a useful high protein food crop. 

The tubers can be used much like potatoes, but they are more nutritious and taste amazing. In fact it’s my favourite perennial vegetable and here at Incredible Veg I’ve got some exciting new accessions in my collection thanks to my good friend Rhizowen from Radix4Roots. I have both diploid and triploid types growing. The triploids which hail from more northern areas of the states aren’t able to produce seeds but the diploids can with the aid of pollinators. So I’m hoping that conditions will allow for pods to form on our plants and go to produce some seed. Well, I can dream!

To keep track of all the different accessions and for ease of harvest I grow them in large 40-50L bottomless pots rather than let them loose in the veg garden. They like moist conditions to grow well and need climbing support for the vines. I mix peat free compost and a bit of potting grit in my pots and use 8ft canes to support the vines. First shoots appear in the spring, vines begin to climb in the summer, followed by scented dusky pink/maroon leguminous flowers in late summer. The vines die back in autumn and the tubers themselves are hardy and can be left in the pots (or the ground) over winter. In my experience it takes about two years to obtain a decent yield of tubers for eating.

Apios americana or Groundnut, Hopniss
Apios americana also known as Groundnut or Hopniss, freshly harvested tubers. The plant forms long rhizomes with edible tuberous swellings that look like strings of beads.

Below are some of our trial Apios americana plants tucked between our two tunnels which create a bit of a sheltered micro climate, hoping to extend the season.

Apios americana plant trials
Apios americana, some of our trial plants between our two tunnels. Potted up in spring 2019, these will be transplanted into much larger bottomless pots next year with 8-10ft canes. Most of these are diploids with the potential to produce pods and seeds given the right conditions.
Apios americana, Groundnut or Hopniss harvest
Apios americana, Groundnut or Hopniss tubers harvested in their second year. Planted in spring 2018, tubers were harvested in Autumn 2019.

Here are some two year old plants grown in large bottomless pots. As long as the compost is kept moist the plants do really well grown like this and tubers can be harvested by tipping out the containers. Most tubers will have clustered in the pot while the plant is still able to draw nutrients from the soil.

Apios americana vines
Apios americana also known as Hopniss or Groundnut. Vines begin to climb from spring into summer. Good support is needed to produce vigorous vines. Here are some of our container grown plants (in bottomless 45L pots) with 8ft canes.

Apios americana starts to flower in late summer producing exquisite scented dusky pink blooms.

Apios americana, Groundnut or Hopniss flowers
Apios americana, Groundnut or Hopniss produce beautiful perfumed blooms. This plant has it all, delicious tubers, attractive vines and flowers and the ability to fix nitrogen.

Although most tubers are about 2-5cm in size, much larger tubers can be grown with improved varieties. Here’s a pic of one of our largest ever tubers which reached the size of a hen’s egg.

Apios americana, Groundnut or Hopniss tuber
One of the largest tubers we have harvested from our stock – about the size of a hen’s egg. Tubers generally are 2-5cm in size but tubers from some improved varieties can get much larger.

The tubers can be used much like a potato but are higher in protein, calcium and iron. We sauté them in olive oil with sea salt and oregano but they can be also be boiled or roasted.

Sautéed Hopniss tubers
Sautéed Hopniss tubers (Apios americana) thinly sliced and sautéed in olive oil, sea salt and oregano, absolutely delicious.