When the late artist Christo and his wife Jeanne-Claude wrapped something monumental — the rolling hills of Marin in their “Running Fence,” the Pont Neuf, Central Park — the thing underneath was already something beautiful.

Or important — the Reichstag in Berlin.

Ever since early January, so the TV views of it would not be spoiled at the Rose Parade, the Norton Simon Museum at Orange Grove and Colorado boulevards in Pasadena has been wrapped in Christo-scale scaffolding, its famous gardens closed off by Jeanne-Claude-akin construction fences, so extensive a covering that passers-by could easily be excused for believing that the Norton was temporarily closed down, given the huge scope of the work.

But the beautiful, and important, museum itself is not closed down at all — still open noon to 5 each Monday, Thursday, Sunday, and from noon to 7 Fridays and Saturdays.

Only the gardens are temporarily inaccessible, and only until this coming fall, and the NSM’s upcoming 50th anniversary parties, which museum staff hope will be held in October, depending on the always undependable schedule of the renovation projects underway.

Museum veep Leslie Denk invited me over to check out all the action Monday afternoon, noting that “it’s been a challenging start of the year.”

That’s an understatement for the Altadenan — while her family’s home was spared from destruction in the Eaton fire on the night of Jan. 7, they were refugees from it for two weeks due to damage.

And the construction at her place of work had begun Jan. 6.

Challenging.

It’s hard for your native Altadenan/Pasadenan scribe to believe that it’s fully half a century since industrialist Norton Simon took over the struggling Pasadena Art Museum campus at city-owned Carmelita as a place to hang his extraordinary collection of Old Masters and Impressionist masterpieces, not to mention his huge cache of Indian art.

But it has been. And while Frank Gehry has already given an update to the eccentric and by-now beloved Kelsey & Ladd building’s trim and its interior, and while 25 years ago landscape architect Nancy Goslee Power transformed the gardens into a pond-happy local Giverny filled with Modernist bronzes, there was work to be done.

Flooding would make the decomposed granite garden pathways unusable in the rainy seasons, and the ponds needed new linings. The traffic noise from the two busy boulevards begged for solid garden walls rather than just fences. And, really, no one could see the most famous sculpture in the gardens, “The Thinker,” whose massive self will be moved from its vegetation-shrouded Colorado Boulevard perch to the entrance with its fellow Rodins “The Burghers of Calais.”

We had hopped up onto a wall near the parking-lot driveway to see where the sculpture will soon sit when Leslie said, “To think this all started three or four years ago out of a desire to make this entrance nicer.”

There was a need for a more accessible pedestrian path from Colorado, for sure. And then the plans grew, as plans will.

Now it’s a $14 million improvement project, overseen by Architectural Resources Group, which also handled renovations at Pasadena City Hall and the Huntington Library, with contractors Morley Builders and new signage from ArtCenter’s Wayne Hunt.

The crazy skin of the museum is made up of about 115,000 tiles by San Francisco ceramist Edith Heath, whose firm until the Kelsey & Ladd commission was known for its dinnerware. Until Leslie pointed it out, I had never looked at the tiles up close to see that they are an homage both to the Craftsman wood shingles of the neighboring Gamble House and to the purple mountain majesty of the neighboring San Gabriels. Fortunately, Heath Ceramics is still in business, recreating some of the time-damaged tiles.

By the next rainy season the garden will be protected from washing out with bioswales and footpaths of permeable resin-bound gravel. The great bronze casts of Henry Moore will be back in place. And the community will have been invited over to the Norton for a 50th birthday party and a view of a show called “Gold” for that golden anniversary.

Nostalgic for the PAM of my youth, I popped into the gift store for an Ed Ruscha-designed poster of the first Pop Art show ever, in 1962, right here in Pasadena: “New Painting of Common Objects.” Not Norton’s jam. But now part of his proper legacy.

Write the public editor at lwilson@scng.com