LAGUNA WILDERNESS PARK – Thousands of marijuana plants were found growing in a public park surrounded by a private high school and a tract of upscale homes, authorities said.

Between 2,500 and 4,000 marijuana plants were growing in the Muddy Canyon area of the Laguna Wilderness Park, just outside of Newport Beach city limits, officials said.

On Friday, narcotics investigators from the Orange County Sheriff’s Department were sent to cut down the plants and continue their investigation into how they were cultivated, said Lt. Jeff Hallock.

The plants were first spotted by OC Parks personnel “a few weeks back,” who then contacted the Sheriff’s Department, Hallock said.

Since then, deputies inspected the area with their helicopter, while investigators hiked down in search of evidence and suspects, he said. Deputies also have been monitoring the area, Hallock said, but no arrests have yet been made.

This is not the first time law enforcement officials in Orange County have found marijuana plants growing in the open.

In July 2007, deputies found more than 6,000 marijuana plants in two pot farms in Aliso and Wood Canyons Wilderness parks. Those plants were also located near multiple homes and hiking trails. They were growing with the help of a sophisticated irrigation system that tapped into the sprinkler system for the nearby homeowners association.

The largest outdoor marijuana grown in Orange County, however, was found in September 2006 when 20,000 pot plants were discovered in Mission Viejo.

Investigators on Friday were still trying to determine how sophisticated the irrigation system used to grow the plants in Laguna Wilderness Park was. They also were trying to determine the source of the water.

The plants were located in a rugged area a few hundred feet south of Sage Hill School. The region is flanked by the 73 toll road to the east and Newport Coast on the west, and is in the jurisdiction of OC Parks. A Newport Beach gated community is to the south.

It was not immediately clear how long the plants have been growing, Hallock said.

At about 7 a.m. Friday, Sheriff’s officials hiked into the area to pull the plants out by hand, he said. The department’s helicopter will then be used to lift hundreds of plants at a time to be kept as evidence.

Investigators are asking anyone with information to contact officials at 714-647-7000. Anonymous tips can also be made via Orange County Crime Stoppers at 855-TIP-OCCS, or 855-847-6227, or occrimestoppers.org.

Contact the writer: 714-796-7949 or shernandez@ocregister.com

Click here to see a video of the marijuana find.