water
Gardeners often water water plants to ensure they thrive.
The sentence describes gardeners irrigating aquatic plants to ensure they thrive.

Meanings (pronounced /ˈwɔːtər/)
to pour water on (plants, etc.); to provide water to
- She waters the garden every morning.
- Don't forget to water the houseplants while I'm gone.
relating to or living in water — used attributively in compounds like 'water plant', 'water lily', 'water buffalo'
- Water lilies cover the surface of the pond.
- Water plants need full submersion.
Word origin
From Old English wæter, from Proto-Germanic *watōr, from Proto-Indo-European *wódr̥. The same root produces Greek hydōr ('water', whence 'hydraulic', 'hydrogen'), Russian voda ('water', whence 'vodka'), and Sanskrit udán-. The verb 'to water' (to supply water to) is derived from the noun.
Fun fact
The word 'water' is among the oldest reconstructible Indo-European words — the Proto-Indo-European root *wódr̥ has been spoken (in changing forms) for at least 6,000 years. Russian 'vodka' is a diminutive of 'voda' ('water') — literally 'little water' — and shares the same root as English 'water', Greek 'hydōr', and Sanskrit 'udán-'. One word, six millennia, dozens of descendants.