Below you can find the It's the tallest of all grasses; one type grows to 120 feet with a stem circumference of 3 feet Jeopardy Words Answer. The answer to It's the tallest of all grasses; one type grows to 120 feet with a stem circumference of 3 feet has 6 letters. This clue belongs to the Botany category and is part of Jeopardy Word Level 696. If you scroll near the bottom you will find other clues and answers part of level 696