To genus Apios (family Fabaceae)
belongs a few species of herbaceous climbers which are native to east Asia and
North America. They all create underground tubers which are edible in case some
of them. Especially 3 species are known to have delicious tubers and they are
sometimes cultivated.
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An inflorescence of Apios fortunei (Japanese Groundnut) |
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Boiled tubers of two varieties of Apios tuberosa (American Groundnut) |
The most known species is Apios tuberosa = A. americana (American Groundnut).
It grows in wild state in North America and is cultivated in numerous varieties worldwide
(but rarely). It is frost hardy perennial. Some accessions are hardy to less
than -30C degree (=-22F degree), but other southern varieties are less frost
resistant. It can be propagated by seeds (only these ones which bloom and
creates seeds) or only by tubers. One plant creates very numerous tubers on
long rhizomes. They have very good taste when boiled or baked and very soft
skin (they do not need be peeled). The seeds and young seed-pods are also
edible after cooking. The forms which
bloom have very ornamental flowers in medium size inflorescences (but my plants
have not flowered so I have not their photo). I grew two varieties: one
unnamed, but improved from Virginia (climber about 2-3m = 7-10ft tall, which
creates large to medium size oblong tubers and is very frost hardy) and the
second larger variety “Nutty” (large climber to 3-4m = 10-13ft tall in my zone
6b, roundish large or medium tubers, never flowering).
Apios tuberosa (unnamed variety from Virginia)
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Young inflorescences |
Apios tuberosa "Nutty"
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This variety creates very tall annual shoots |
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and large roundish tubers |
The second American species, very hard to find and
rarely cultivated, is Apios priceana (Price's
Potato-bean, Price's Groundnut, Traveler's Delight). This is very large (3-5 m = 10-16 ft tall)
herbaceous climber which is much frost resistant and
winters easily without mulching in my zone 6b. It is native to the U.S.
states of Alabama, Mississippi, Kentucky, and Tennessee. It creates only one
turnip-like rhizomatous tuber, which enlarges every year and can grow quite
large in numerous years. The tuber is edible. It can be easily propagated by
seeds (they can be sown direct in the garden after last frosts). It also has
not flowered yet in my experience.
Apios priceana
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This species creates only 1 tuber per plant. It can be quite large after
numerous years. On the photo there are 2 years old tubers |
The third species which I grew is Asiatic Apios
fortunei (Japanese Groundnut, Chinese Groundnut). In my experience my
plants created also single tubers per plant, but with a few long stolons, so I
suppose that this species is intermediate between previously described –
creates a few tubers (not as numerous as A.
tuberosa but not one as A. priceana).
It is the only species which flowered freely in my cultivation. The flowers are
lovely close up and curious but not very showy. I have not tasted the tubers of
last two species yet, but they are described as delicious. It is probably full
frost hardy in zones 5/6 but I have not wintered it outside yet.
Apios fortunei
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Plants in late spring |
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and in summer |
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The inflorescences of this species are lovely close up but not very showy |
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The tubers with long stolons |
There exists a few other species of groundnuts (Apios spp.). If you have available seeds or tubers any of them please write to me.
Thank you,for posting! I am thinking of adding ground nuts to my garden this year and your blog had all the info I needed
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