Brambles of Mordor
The large plateau in the northwest of Mordor was known as Gorgoroth, where the furnace and forge of the Ring lord Sauron were held. It was bragged that nothing grew in this poisoned land. The vast desolation of Gorgoroth was usually what was conjured up in the popular conception of "Mordor", though to the south and east of Gorgoroth plateau lay the more fertile lands of Nurn which contained vast slave-tilled fields. Still, Gorgoroth was the centre of Sauron's dominion and commonly considered to be a lifeless hell-on-earth.
However, the Red Book of Westmarch says that the region was actually not utterly devoid of flora. There were some plants that did grow in northern Mordor: running parallel to the outer Ephel Duath and the Gorgoroth plateau there was a smaller inner range of mountains called the Morgai. In the valley between the two mountain ranges, there was enough shelter and runnoff water for some plantlife and a basic ecosystem to survive. It was a dying land, as thousands of years of Sauron's supernatural devastation caused by the fires of Mount Doom had worn down what had originally grown there, but it was not quite dead yet.
In sheltered places twisted tree-forms and stunted grey grasses grew. The leaves were shrivelled with Sulphur vapour and maggot hatchlings. Nowhere in Middle-earth did brambles ever grow so large and fierce. These Brambles of Mordor were ugly with foot-long thorns, which were barbed and sharp as the knives of the orcs that came from Mordor. They sprawled over the land like coils of steel wire. They were truly the flowers of Mordor, for thy represented Mordor exactly; cruel, fierce, and disgusting.