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- 11. Newly Planted Trees Need Protection - Top
- Young trees are characterized by soft, fleshy bark and tender stems. That's what makes them so vulnerable to the ravages of climate and critters in our harsh desert environment. But there are good things you can do to protect your youngster trees, and grow them on to healthy adulthood.
The first line of defense for newly planted trees is to protect the trunk with tree wrap. This is especially important for trees that have green bark, like the palo verde, or thin bark like citrus and other fruit trees. During autumn and winter, the sun is at a lower angle, and thus shines more directly on the trunk wood. On sensitive trees, this can cause a burning or scalding of the bark and underlying cambium. Damage and death of the trunk tissue is most likely to occur on the south or southwest sides of the tree.
Wrapping the trunk with a paper tree wrap or white plastic sleeve will shade the trunk and protect it. These speciality products can be purchased at garden centers and home supply stores. As the tree grows the trunk toughens and the crown grows to provide natural shading of the trunk, making the trunk wrap unnecessary. The wrap should be left on through the winter and removed in mid to late spring when the sun is at a higher angle in the sky.
The second line of defense is protection against marauding wildlife. Rabbits love the soft wood of a newly planted tree. So do pack rats and ground squirrels. Protecting the trunk is most important. This can be done by making a cylinder of chicken wire or hardware cloth and surrounding the trunk. The cylinder should be wide enough to stand several inches away from the trunk and at least 18 inches high. Bury the base of the cylinder 3 inches into the ground to deep rabbits from digging under or uprooting it. Finally, secure the cylinder with stakes to prevent it from being pushed over.
Javelina provide a more difficult challenge. They are big enough to knock most things over, including hardware cloth, but they don't like to walk on unsteady ground. I have heard from gardeners who have had great success lining their gardens or valuable plants with a four foot wide band of rubble rock. These are large rounded rocks are used primarily for holding step slopes against erosion. They provide unsteady footing for hooded javelina and thus discourage them. Give it a try around your new trees. You can also use low-voltage electric fencing. A single-strand wire placed 8 to 10 inches above the ground on stakes and insulators delivers an unpleasant shock to ward off javelina.
The third line of defense is from the cold of winter. This is especially important for frost sensitive trees like citrus, guava, jacaranda, bottle brush, and others. We do have cold weather here in Tucson. The first hard freeze usually occurs around Thanksgiving. Young trees are especially vulnerable to the cold. For small trees, cover them completely with a sheets or light weight plant frost blankets. If temperatures get very cold, below 25 degrees, place a heat source under the cover. A utility light with a 60 or 100 watt bulb works well. If you can't cover the entire tree, wrap the trunk and large branches with newspaper several sheets thick. This will hold core heat in the wood and protect it from damage.
Finally, I think the biggest impediment to the healthy growth of young trees is staking and wiring. Tight staking that does not allow the young tree trunk to flex and move in the wind will causes an atrophy condition. The trunk never develops the strength it needs to stand on it's own. Staking wires left wrapped around the the trunk or branches too long will begin to cut into the wood and severe the life-giving cambium layer. The tree can be completely girdled! Stakes and wires for support should never be left on longer than one year.
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Written by John Begeman, College of Agriculture, the University of Arizona, 520-626-5161.
Material originally appeared in Arizona Daily Star gardening column, on November 12, 2000
- Updated: November 12, 2000
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