undergrow means to grow to an inferior, or less than the usual, size or height. Lexicurio rates it Sui generis — a strength score of 88 out of 100.
Etymology
From under- + grow.
verb
- To grow to an inferior, or less than the usual, size or height.
- To grow underneath.“Descending the side of the levee, he penetrated the rank density of weeds and willows that undergrew the trees until the river's edge, shouting Victor's name.”