Young Citrus Trees Get a Chicken-Wire Ring Stuffed With Pine Straw or Hay Above the Graft Before Severe Freezes, UF/IFAS Leon County Says

Young citrus trees need a freeze plan. UF/IFAS Extension Leon County, in a Nov. 3 garden calendar by Extension Agent Emeritus David Marshall, says young trees should be protected before severe freezes, especially the trunk above the graft. The method is a ring of flexible wire, such as chicken wire, placed around the trunk and stuffed with pine straw or hay. Severe freezes do not usually arrive until Christmas or later, the post says, but it pays to have a plan.

Why the Trunk Above the Graft Matters Most

Citrus trees are grafted, with the fruiting variety joined to a rootstock. Okaloosa County’s Larry Williams writes that the rootstock, trifoliate orange, passes its cold hardiness on to the variety grafted onto it, so the graft union is the spot worth guarding.

UF/IFAS makes the same point in its guide to cold protection of landscape plants, written by Sydney Park Brown and colleagues. The publication does not single out citrus, but it says grafted or budded plants can be protected by insulating the trunk with commercial tree wraps or with soil mounded one to two feet high. That way the plant can re-sprout from above the graft if the branches freeze. The wrap or mounded soil comes off each spring.

Louisiana State University’s AgCenter, in a home orchard article by Michael Polozola and Anna Timmerman, calls freeze injury the main limit on citrus in Louisiana home landscapes. The article says citrus does not reliably go fully dormant, so it stays vulnerable through much of the season. Successful production, it says, depends on timely, effective protection, especially during sudden temperature drops or long freezes.

Marshall frames the whole task as preparation rather than reaction. The post notes that citrus will be ripening in the coming months, and puts the protection on the November to-do list well ahead of the freezes it says usually come later.

Wire and Straw, Soil Banks, and Tree Wraps Compared

The Leon County ring of chicken wire stuffed with pine straw or hay is one of several ways to insulate a young trunk, and Florida extension agents do not all recommend the same one.

Matthew Orwat, the horticulture extension agent in Washington County, Florida, wrote in a December 2022 post that young trees can be wrapped with commercial tree wrap or have soil mounded up to 2 feet high to protect the graft. For established trees he suggests a cone of mounded soil. He also advises against mulching over winter, because mulch blocks heat rising from the soil.

Larry Williams of UF/IFAS Extension Okaloosa County is stricter. In a December 2022 post, he recommends mounding soil around a young trunk high enough to cover the graft union and lower trunk, built before cold weather arrives. He warns that materials other than soil used to wrap the trunk may kill the tree, because trunk temperatures can climb too high on warmer days.

The advice differs mainly in the material. The Leon County wire ring uses pine straw or hay, while the Washington County and Okaloosa County posts lean on soil. All of the Florida sources agree on the goal: keep the graft union from freezing.

Timing, Covers and Taking the Protection Off

Protection works only if it is in place before the cold arrives. UF/IFAS says covers should go on ahead of a freeze, and that in-ground irrigation should be turned off before freezing temperatures arrive. Covers should not rest on the foliage and should reach the ground to trap heat, and plastic should be vented or removed on sunny days.

Cold thresholds vary by place. A California columnist’s November advice, covered in a Mendocino County citrus-covering story on this site, puts the covering trigger at 29 degrees held for 30 minutes.

Okaloosa County’s Williams recommends cloth rather than plastic and says to remove it as soon as the cold passes, ideally the next day, since leaving it on can break dormancy and increase cold injury. He also advises watering early in the day before cold arrives and keeping the soil under the tree free of mulch and grass so it absorbs and releases daytime heat overnight.

What happens after a freeze matters too. A UF/IFAS fact sheet, Recovering from Freeze Damage by Stephen H. Futch, says that if some leaves and green twigs remain above a bank or wrap, the tree can usually regrow without special steps. It advises removing the covering from a few trees each week to check that the bark is firm, because damaged trees can sweat under the covering and become infected by a fungus.

The same fact sheet says trees that were not banked should not be banked right after a freeze, since that can cause sweating and worse damage. The better move is to wait for the next freeze forecast. Pruning, fertilizing and spraying should wait until the risk of freezes has passed.

Orwat’s Washington County post adds several details for the days around a freeze. He says to run microsprinklers for the entire freeze, starting at 36 degrees and keeping them on until it reaches 42, and to aim the emitter on the windy side about 1 to 2 feet from the trunk so water covers the graft union on larger trees. Sprinklers do not protect fruit, so he says to harvest all fruit before temperatures drop below 25 degrees.

He also says not to cover trees with plastic tarps, which do not protect them and can overheat them in sunlight, and to place windbreaks north and east of trees. Well-watered soil holds more heat, he adds, and well-hydrated trees handle wind-driven freezes better.

This article was produced with AI assistance and edited for accuracy against the sources linked above.

Image: Burkhard Mücke – CC BY-SA 4.0/Wikimedia Commons