Alfresco art is the city's grace Enjoy art outside, from Dale Chihuly's glorious and sometimes gloppy glass at New York Botanical Garden to an eccentric 'Corner Plot' near Central Park

When I was a child in Manhattan in the 1970s, outdoor art usually meant either graffiti or brawny metal monoliths. But New York City has become a less corrosive place, and frailer artworks have a better chance at survival. The New York Botanical Garden has tested that proposition by festooning its grounds with blown-glass baubles and hedged its bets by stationing security guards near every piece. But public parks all over the city are sprinkled with works that rely on the kindness of strangers. It's an indicator of how much the city has changed in recent decades that artists can leave intricate, fragile creations out for months and be reasonably confident that they will remain intact. New York Botanical Garden Translucent, birdlike bodies, each with a graceful heron's neck and a single undulating leg, nestle among the coleuses.

An agglomeration of yellow nodules is suspended above the leafy flora like a colossal mutant squid. A huge cluster of roundels, like bright foil balloons or Christmas ornaments, hovers above another stretch of greenery. These eerily lifelike objects, ensconced amid vegetation, are the glass creations of Dale Chihuly, who is making his first large-scale foray into New York City. Chihuly has inserted sculptures large and small into and around the Enid Haupt Conservatory at the garden, itself a miracle of glass construction. Other oversized works can be found throughout the campus: at the Rose Garden, the Children's Adventure garden and the Nolen Greenhouses. Chihuly doesn't blow the glass himself -- he has teams of assistants, artisans and contractors to do that -- but the designs are distinctively his own, at times mimicking the natural world, at others conversing with it. They waver between cheap spectacle and genuine inspiration. Two rowboats overflowing with iridescent glass foliage float in the outdoor ponds. Onionlike forms in a surreal range of hues bob and sway alongside them. All of this flashy stuff grabs our attention shamelessly. But after staring for a few minutes at these manufactured marvels, our eyes begin to adjust, and we notice the graceful plants and darting fish that provided the artist's models. Chihuly almost makes the real thing look fake. Can that impossibly sculptural lily pad actually be alive? His formulaic mimicry draws our attention to what is really weird and marvelous in our surroundings. Less successful are his stand-alone works that challenge us to gape at their monumentality. The pink crystal monolith towering outside the conservatory, for instance, looks like a huge candy-coated sex toy. The neon tower, a 20-foot column of coiled, wormy green filaments, is merely garish. The exhibit's special admission price of $20 (notwithstanding sponsorship by Target) and an additional $10 parking fee will discourage some from visiting this bucolic blockbuster, which is a shame. New Yorkers who can't easily leave the muggy gray city in summertime could use a day in this psychedelic Eden. "Chihuly at the New York Botanical Garden," through Oct. 29 at Bronx River Parkway and Fordham Road, the Bronx. Advance tickets through Ticketmaster advised (212-220-0503). For more information, visit nybg.org. Riverside Park Those who don't want to spring for Chihuly can get a fix of open-air art in Riverside Park, where sculptures burrow, crouch and blend in with the scenery. The Riverside Park Fund is celebrating its 20th anniversary with "Studio in the Park," consisting of 11 site-specific pieces by contemporary artists, scattered from 70th Street to 145th. Some of the works have deteriorated quickly, including a tunnel at 84th Street that was lined with sparkling tin foil and already looks like an abandoned sandwich. But several are worth seeking out. Be sure to visit Robert Greenberg's installation in the Rotunda arches of the 79th Street Boat Basin Cafe. The artist has assembled driftwood he found along the Hudson River into a series of mobiles that resemble the desiccated bones of ancient creatures. A monumental skeleton with tail and flippers dangles from one archway, while assorted vertebrae float in another, casting creepy shadows. It's a brilliant, evocative work, even more dramatic when illuminated at night. Also check out Fabian Marcaccio's ginormous painting-sculpture in the 72nd Street underpass, which veers between meticulous realism and gooey, sensual abstraction. Careful renderings of Pop Art staples -- a can of Coke, a bottle of Lysol, a packet of Milk-Bone dog biscuits -- jostle together in a Jacuzzi of shopper gratification. Around these cheerful products run waterfalls of viscous silicone that suggest a consumerist fantasy being washed away in an apocalyptic maelstrom. Half a block away, Orly Genger's "Puzzlejuice" spreads out glamorously across a sea of rocks. The artist crocheted lengths of nylon rope into a colorful quilt of color that looks at once industrial and cuddly. "Studio in the Park," through Sept. 16 at Riverside Park between West 72nd and West 145th streets, Manhattan. A map specifying the locations of all the sculptures is available at riversideparkfund.org. Central Park Sarah Sze's "Corner Plot" occupies a spot just outside Central Park, but its character is staunchly urban. It will take a minute to orient yourself around this eccentric object, which looks at first as though the corner of an apartment building -- specifically, the white brick co-op across Fifth Avenue -- has landed at your feet, or is bursting out of the ground. You need to get down on your hands and knees to really appreciate "Corner Plot." Look inside the windows, where Sze has created a mysterious interior underground filled with a wacky mix of items: towers of toilet paper, a fire extinguisher, piles of pushpins, a stack of bath towels, cartons of salt and a magnifying glass, to name a few. Light radiates from a desk lamp suspended in the depths. Is this some kind of postmodern bomb shelter? A twister-tossed dwelling like Dorothy's Kansas homestead, updated? An archeological relic ahead of its time? Sze's meaning is deliberately murky, but nothing could be clearer than the wonder she manages to generate in a saturated corner of the city. Sarah Sze's "Corner Plot," through Oct. 22 at Doris C. Freedman Plaza, Fifth Avenue and 60th Street, Manhattan. Lincoln Center The Public Art Fund, which sponsored Sze's work, also made possible an explosive piece over at Lincoln Center. "Big Pleasure Point" is like a ballistic star slung together out of projectile boats. Nancy Rubins, who generally sculpts from salvage, convened and cantilevered more than 60 kayaks, canoes, small sailboats, surfboards, jet-skis, paddleboats and catamarans into a huge gravity-defying mass that teeters over the heads of passersby. It is everything public art should be: friendly and fearsome, exuberant and authoritative, spectacular without ever succumbing to melodrama. Nancy Rubins' "Pleasure Point," through Sept. 4 at Lincoln Center.