
1) Kalmia 2) Kalmia angustifolia 3) Pig laurel 4) Poisonous to young stock 5) Sheep laurel
Found on
https://www.crosswordclues.com/clue/lambkill

• (n.) A small American ericaceous shrub (Kalmia angustifolia); -- called also calfkill, sheepkill, sheep laurel, etc. It is supposed to poison sheep and other animals that eat it at times when the snow is deep and they cannot find other food.
Found on
http://thinkexist.com/dictionary/meaning/lambkill/

(species Kalmia angustifolia), an open upright woody shrub of the heath family (Ericaceae). Lambkill is 0.3–1.2 m (1–4 feet) tall and has glossy, ...
Found on
http://www.britannica.com/eb/a-z/l/9
Lamb'kill` noun (Botany) A small American ericaceous shrub (
Kalmia angustifolia ); -- called also
calfkill ,
sheepkill ,
sheep laurel , etc. It is supposed to poison sheep and other animals that eat it at times when the snow is deep and they cannot find other food.
Found on
http://www.encyclo.co.uk/webster/L/8
No exact match found.