As the first botanical history of World War II, Plants Go to War examines military history from the perspective of plant science. From victory gardens to drugs, timber, rubber, and fibers, plants supplied materials with key roles in victory. Vegetables provided the wartime diet both in North America and Europe, where vitamin-rich carrots, cabbages, and potatoes nourished millions. Chicle and cacao provided the chewing gum and chocolate bars in military rations. In England and Germany, herbs replaced pharmaceutical drugs; feverbark was in demand to treat malaria, and penicillin culture used a growth medium made from corn. Rubber was needed for gas masks and barrage balloons, while cotton and hemp provided clothing, canvas, and rope. Timber was used to manufacture Mosquito bombers, and wood gasification and coal replaced petroleum in European vehicles. Lebensraum, the Nazi desire for agricultural land, drove Germans eastward; troops weaponized conifers with shell bursts that caused splintering. Ironically, the Nazis condemned non-native plants, but adopted useful Asian soybeans and Mediterranean herbs. Jungle warfare and camouflage required botanical knowledge, and survival manuals detailed edible plants on Pacific islands. Botanical gardens relocated valuable specimens to safe areas, and while remote locations provided opportunities for field botany, Trees surviving in Hiroshima and Nagasaki live as a symbol of rebirth after vast destruction.