One of Portland's most celebrated outdoor spaces is expanding.

This week, the Portland Japanese Garden's leadership announced it was in the process of closing the funding gap on a major $33.5 million dollar expansion, led by the prestigious Tokyo-based architecture firm Kengo Kuma and Associates. While leaving the five existing gardens untouched, the project will expand the 5.5 acre property by about 11,000 square feet and add three new LEED-certified buildings and seven new garden spaces.

In addition to a new bonsai terrace, moss hillside garden, and a chabana (tea flower) garden, the new construction will include:

An overhauled entrance more in tune with the gardens themselves. Say goodbye to the generic driveway, say hello to a water garden!

more in tune with the gardens themselves. Say goodbye to the generic driveway, say hello to a water garden! A cultural village and courtyard for demonstations and performances

for demonstations and performances A 22-foot high Japanese castle wall built by a 16th generation Kyoto mason.

Speaking at a press conference outside of the garden on Tuesday, KKA's design director, Balazs Bognar, was careful to note the restricted nature of the project.

"The gardens are at the heart of the design. To be very clear, we are not touching the existing gardens," he said. "Those in themselves, if I dare say, are perfect. There's no need for further editing. What we are doing as an architect team is simply to fill in the gaps and to provide what is not there. And to allow visitors to come and put themselves in the right frame of mind before they enter the gardens."

After an August groundbreaking, the gardens will close to the public in September while construction begins. PJG expects to reopen to visitors next spring, with construction on the new areas continuing until early 2017. In the meantime, the PJG board still needs to raise roughly $13 million. (The state of Oregon has contributed $1.5 million to the project.)

"It's an incredibly exciting moment," Bognar continued. "We are on the leading edge of something really, really great. This is our first public project in North American. There is no other place like this in the world. Not only do you have five incredible examples of the art of Japanese garden design, but you have the combination of Pacific Northwest atmosphere, with the firs and pines in the background. It's a combination that doesn't exist anywhere else. This is a very, very big deal."

For the backstory behind this project, read Portland Monthly's 2013 feature story on the leadership's ambitions. And to see renderings of the new gardens, visit the PGJ Cultural Crossing website.