Luxuriant Growth
noun, verbal noun
Something that is overgrown and luxuriant must have quite the luxuriant growth. Lots and lots of growth.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
庭に雑草が繁茂しているので、この週末に草刈りをします。
Our yard is overgrown with weeds, so I’m going to mow them this weekend.