striga (witchweed), usually Striga lutea 独脚金（巫师草）
sun spurge, Euphorbia helioscopia 泽漆
sunflower, Helianthus annuus 向日葵
sycamore, Acer pseodoplatanus 挪威枫
tansy, Tanacetum vulgare 菊蒿
thistle, creeping, Cirsium arvense 丝路蓟
spear ('Scotch'), C. vulgare 大翅蓟（来自苏格兰的）
thorn-apple, Datura stramonium 曼陀罗
thoroughwort, Ageratina adenophora 贯叶泽兰
thrift (sea-pink), Armeria maritime 海石竹（海粉红）