Last year water hyacinth choked Delta marinas and waterways with huge clots of green.
In normal years, the plant would die off in winter, but this year's mild temperatures and the drought have allowed the invasive weed to drop seedlings.
Vicky Waters of the California Department of Boating and Waterways says herbicide spraying has already begun and it's three weeks earlier than last year.
Waters says mechanical harvesters will also be used to remove water hyacinth.
"We've seen that it is effective in certain areas and at certain points of the treatment season so we're going to be using that again more consistently this year."
River Point Landing in Stockton was effectively blocked by water hyacinth from August to December last year.
Harbormaster Vince Moreno hopes the early start will bring better results this year.
"If they can't get a handle on it earlier or be more aggressive that it'll be that bad every year probably."
Spraying has also started this week for other invasive weeds including egeria, spongeplant, and curly leaf pond weed.
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