Russian cactus vs Russian thistle

Russian cactus and Russian thistle both are nouns.

Word	Noun	Adjective	Verb	Adverb
Russian cactus	Yes	No	No	No
Russian thistle	Yes	No	No	No

As nouns, Russian cactus and Russian thistle are synonyms defined as:

Russian cactus and Russian thistle: prickly bushy Eurasian plant; a troublesome weed in central and western United States

Other synonyms of Russian cactus include Russian tumbleweed, Salsola kali tenuifolia, tumbleweed.

Russian cactus (noun)	Russian thistle (noun)
prickly bushy Eurasian plant; a troublesome weed in central and western United States	prickly bushy Eurasian plant; a troublesome weed in central and western United States