Frozen orange tree

Leaves on an orange tree wilt in Mandeville, Louisiana, on Jan. 19, 2018, after a hard freeze. Temperatures across much of south Louisiana were the coldest in over 20 years.

Citrus trees like lemon, orange and kumquat thrive under the warm conditions of the tropics.

Most of the time, that means they’re right at home in south Louisiana.

Not this winter.

Citrus trees this season have had to deal this month with sleet and snow — even in southern Plaquemines Parish — plus several nights in a row below freezing that produced subzero wind chills as far south as Hammond.

In other words, anything but tropical.

And for a lot of those trees, one expert says, the conditions may have been more than tough — they may have been terminal.

“You could be looking at a radically different-looking landscape,” said Lee Heyl, chief operating officer of Windmill Nursery, the largest wholesale grower on the north shore.

Heyl said he does not yet know how bad the damage will be, as it takes several days of nonfreezing temperatures to determine whether a plant was killed, but he'll start finding out Monday.

With much of the area having seen its coldest temperatures in more than 20 years, though, Heyl isn’t too hopeful about many tender plants — especially citrus trees.

“Satsumas — there’s a very good chance that some would have been injured if not killed,” he said.

However, John Colclough, who owns about 750 citrus trees in lower Plaquemines Parish, said he remains optimistic.

Colclough said he hasn’t been down to investigate yet, but his trees have been through many freezes before, and he thinks they probably made it through this one, too.

“I do not yet know if we have any trees that are dead, but I do not suspect it,” Colclough said, though he noticed wilting and a large loss of leaves when he went to see his trees after freezes earlier this winter.

Heyl also urges people not to assume anything and to wait before trimming back any citrus trees. As for non-tropical plants, he said they may look dead, but that doesn’t mean they are.

Some plants may have gone dormant in one of the earlier freezes to protect themselves — as they do farther north, Heyl said — so it’s best to take a wait-and-see approach, or look up information about the particular plant online if you’re in doubt.

“The key to this thing isn’t what happened this week. It’s what happened prior to this week,” he said. “If they’re not hardened off, they’re dead.”

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Heyl added that some plants might have been lost because of improper protection. Covering plants in plastic is one of the biggest mistakes people make, he said, because it’s actually conducive to cold. Covering plants with blankets or even newspaper is a better option. He also said to make sure plants are watered before a freeze.

But for some plants, such as frail tropical plants — ones without a tree trunk — that may not be enough. If they’re not looking good now, you might as well forget them.

“In New Orleans, you can have pretty tropicals in your yard for 10 years, and then you get a good cold freeze like this — it’s all gone,” said Phillip Lowery, a salesman at Windmill.

But it wasn’t just the cold temperatures that killed plants, Heyl said. What caused the most damage, he said, was the wind, which remained strong throughout the cold snap, with New Orleans Lakefront Airport recording a wind chill of 3 degrees Wednesday morning.

High winds combined with frigid temperatures will cause most citrus losses, Heyl said, though, ironically, trees can be saved by another cold-weather event: snow.

“Snow is a good thing. It helps protect the plants — plants are kept moist. It’s actually an insulator. It’s a good thing to have. Better than ice,” Heyl said.

But it’s not all bad news. He said some warmth-loving plants, like palms, are actually pretty cold-resistant, so he’d be surprised if there’s a major loss of them.

Even if the trees survived, Heyl urges people not to let their guard down, as winter is far from over.

Still, when freezes as hard as the one last week come along, there’s only so much you can do.

“Everything that died or everything that will die this winter is not a result of bad care — it’s just a result of Mother Nature flexing her muscle. She still rules the game,” Heyl said. 

Follow Nick Reimann on Twitter, @nicksreimann.