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| Apios americana |
By Kim Willis These articles are copyrighted and may not be
copied or used without the permission of the author.
How would you like a vine that’s native, edible, medicinal,
and has pretty chocolate colored flowers? I have some growing rampantly in my
yard, but I bet most gardeners have never heard of the plant. Hopniss or
groundnut, Apios americana, is an unusual plant that more gardeners
should try growing. I’m going to call it hopniss because groundnut is also a
common name for the peanut. It’s also
called Indian Bean or Indian potato.
There is one other species of hopniss in the US called Price's
Groundnut (Apios priceana). It is extremely endangered and found in one small
area of Illinois. The flowers of this species are a light pink. It has one larger tuber instead of many small
ones.
Hopniss was a staple in the diet of many Northeastern Native
American tribes and may even have been selected for certain traits and grown as
a cultivated crop. It’s native from southern Canada to deep in the southern US
from the east coast to the Rockies. It is becoming rarer and is listed as
endangered in some states. A few
nurseries grow the plant and Louisiana State University has tried to develop
hopniss into a commercial crop. Other universities have studied the plant for its
medicinal qualities. There is a small
commercial crop grown in Japan.
The native habitat of hopniss is at the edges of moist
woodlands and along rivers and streams in moist bottom lands. Hopniss is a vine
or it sprawls over the ground if it doesn’t have something to climb. It will
climb to 8 feet or more in a good site. The leaves are arranged
alternately, pinnately compound, consisting of 5-7 oval leaflets. They remind
me somewhat of wisteria leaves.
Two butterflies use hopniss as a larval food plant, Epargyreus
clarus (Silver-spotted Skipper) and Thorybes bathyllus (Southern
Cloudywing). Deer feed on the foliage and small animals eat the tubers.
Hopniss flowers are intriguing. Bloom time is mid to
late summer, with August being the bloom period in Michigan. The plants
produce clusters of “curly” looking milk chocolate colored flowers, with a
flared “hood’ consisting of two fused petals, two tiny petals near the bottom
and a curious curved tube in the center that protects the pistil and
stamens.
The end of the tube appears to be buried at the top of the
hood but if you so much as touch the curved tube it will coil away from the
hood wall and the tip will slowly split, first the pistil and then the stamens
will poke out. You can watch it slowly happen. I imagine
that an insect landing on the hood area or the curved tube would also provoke
the reaction. After the flowers curved part has been activated the
hood folds around the curved tube and is said to be “tripped”.
It's not known for sure what pollinates hopniss. Leaf cutter bees and flies do visit the
plants. Leaf cutter bees have been seen to trip the “tube”. Honeybees occasionally
visit the flowers, but since honeybees aren’t native, they are not the original
pollinator. However, the subject of
pollination may not be important, as many plants do not produce seeds.
Hopniss comes in two strains, a diploid and a triploid. This
refers to sets of genes that the plant has. It’s impossible to tell whether hopniss
is a diploid or triploid by looking at it. In the north most hopniss is triploid
and does not produce seeds. Reproduction
is from the little tubers the roots form.
Farther south and in a distinct region around the Black River in central Ontario,]some
stands of hopniss are diploid and produce narrow, bean like, slightly curved
pods. The pods have maroon seeds that darken to chocolate brown when dried. The
pods split when mature and “shoot” their seeds.
Flowers and seeds of hopniss are edible. The flowers are used medicinally in the
treatment of diabetes. The beans were dried and ground into flour or boiled and
eaten by Native Americans.
It’s the little tubers that form along the rhizomatous roots
that earn hopniss the name groundnut and that are the primary food product. The
tubers form along the roots like knots in a rope. They are about the size of your thumb or
smaller. They are dark brown on the outside and creamy yellow inside. The texture is much like a potato.
These little tubers have about 3 times as much protein as
potatoes and a different type of starch called oligosaccharides. They also have lectins, a chemical found
in raw beans. They are high in iron and calcium. The tubers should always be
cooked before they are eaten. Even so
some people who eat the tubers will experience extreme gassiness and bloating
and may have diarrhea. It is said that a
sensitivity in some people may build up after consuming it about ten times, causing
an allergic reaction.
Native Americans collected hopniss tubers and dried them on
mats for winter storage. They were powdered and used as a flour or boiled in
soups. Some tubers were sliced and fried as we do potatoes. Hopniss was boiled
in maple syrup to produce a type of preserves.
The taste of hopniss is said to be like a nutty potato and quite good.
Hopniss was one of the native foods that the first European
settlers had to survive on the first winter after they arrived. It remained a
popular winter survival food for many years. Hopniss tubers were introduced to Europe and
other places. Japan embraced them as an edible crop as they were similar to
another Japanese crop.
Hopniss is said to be a signal to archeologists that an
Amerindian site is nearby, so maybe my yard is located on one. The plants
were here when I arrived and this house is over 100 years old. Henry Thoreau is said to have eaten them when
his potato crop failed.
Growing hopniss
Hopniss is a perennial plant and if you want to grow it you
will probably start with tubers, not seeds. Just plant the tubers on their
sides in about 3 inches of soil. It
likes light textured, moist soil in full sun to light shade. The plants fix
nitrogen in the soil like soybeans, so they need little fertilization. It can
take several years for the vines to grow until there is enough tubers for a
harvest. Hopniss is hardy to at least zone 4.
If you grow hopniss for the flowers or for a screening vine,
remember that they spread quite quickly in spots they like. They can take over
a lot of fence or cover a lot of ground. The vines die back in winter and come
back from the ground. Most flowers in
the north will not make seedpods.
Hopniss has few insect or disease problems. They may die
back in very hot, dry weather.
Growing hopniss as a crop is tricky because of the perennial
nature of the plant and the years needed for a crop. You dig up the vines in
early fall after the first frost to collect the tubers. You can’t pull the
vines out of the ground; they need to be dug.
Save some tubers to replant, right there after harvest. Tubers are stored like potatoes, in a dark,
cool but above freezing place.
Medicinal uses of hopniss
Hopness flowers are used to lower blood sugar. I believe a tea
is made with them. Boiled tubers are used as a poultice on wounds. Eating the
tubers is said to lower blood pressure, cholesterol and triglycerides and is
being studied for those purposes.
There are chemicals in the tubers that have anticarcinogenic
properties and one compound, Genistein-7-O-gentiobioside, is being
studied as a treatment for breast cancer. It may also be helpful in colon and prostate
cancer.
Hopniss is an interesting native vine with pretty flowers
and many edible parts. You may want to include it in your garden.
Sources for tubers
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