Thursday, March 30, 2017

Bittersweet Nightshade

'Deadly' Nightshade Warrants Caution

Bittersweet Nightshade [J Goltz Photo]
Bittersweet Nightshade Solanum dulcamara, also known as Creeping, Climbing, or Woody Nightshade, is a toxic plant that is common in New Brunswick.  I have heard naturalists recently trivializing the toxicity of this plant and this post is a reminder that that is an error.  This plant needs our attention.

The nightshades are a large group of plants of the Solanaceae family.  We have 3 species of Solanum here, two being rare.  Bittersweet Nightshade Solanum dulcamara, is common and the plant we are discussing in this post.  It was introduced from Europe and grows in woods and thickets throughout North America, most commonly in northern United States and southern Canada.  It has dark green leaves which are variable in shape, often with two opposite basal leaves.  It has purple, star-shaped flowers with 5  backward-pointing petals, and yellow centres.  The plant is a perennial and the stems are slender, woody and up to 1.5 m long (6 ft).  The deep medium green ovoid berries turn to bright red as they ripen.  The berries hang downward in bunches.

Bittersweet Nightshade [J Goltz Photo] 
Bittersweet Nightshade [J Goltz Photo]
Poisonings by this plant have been recorded in children, horses, cattle, sheep, and a dog.  The toxic parts include the whole plant but especially the green berries.  There are several toxic chemicals in the plant but the main toxin is solanine.

The symptoms of toxicity include mainly acute onset of weakness, staggering, and muscle tremors.  These are followed by respiratory and central nervous system depression and vomiting.  If the patient vomits plant material and it can be identified, it is somewhat easier to treat the toxicity.  Generally treatment is symptomatic.  In one reported case of Nightshade toxicity in a Labrador Retriever pup treatment was very intense for over 2 days before the pup recovered.

Bittersweet Nightshade, UNB Herbarium specimen
From the name of this plant it must not taste very good.  How, then, do animals and children get poisoned?  I am not certain about children, although I expect curiosity plays a role.  However, I can speak for animals.  In livestock the plant gets mixed in with dried forage, e.g. hay.  It is then offered to them to eat and they mistakenly eat it or they have no choice because they are hungry.  In other cases in livestock their pasture is running out and they eat whatever they can find.  In the case of the Labrador pup, there was nightshade growing around the edges  of the fenced back yard and the pup was chewing whatever it found in its environment.  I remember a case where one of my friends went picking high bush cranberries to make jelly.  They had inadvertently also picked some ripe nightshade berries and they were included in the jelly.  Fortunately in that case the jelly tasted very bitter so it was not eaten and destroyed!

In conclusion, Bittersweet Nightshade is not a plant to be ignored.  It should be eradicated from your property and wherever your pets, livestock and children spend their time.  Many years ago we diligently dug up and destroyed all nightshade from our farm for this reason.  It would be wise if you did the same.


Kees, Beckel, Sharp.  Successful treatment of Solanum dulcamara intoxication in a Labrador retriever puppy. CVJ Vol 56, Dec 2015.

Kingsbury, J.M. Poisonous Plants of the United States and Canada. Prentice-Hall

Hinds, H.H. Flora of New Brunswick. Biology Department, UNB

Schneider, M.F. Plants Poisonous to Children and Other People. The Health Association, Rochester, NY

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