Arborvitae Leaves Brown/Gone After Unwrapping Burlap - Ask Extension
Hello Expert, I wrapped my Arborvitae bush with burlap in late fall, as I do every fall to prevent deer from eating the lower leaves. Today, March ...
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Arborvitae Leaves Brown/Gone After Unwrapping Burlap #860320
Asked March 02, 2024, 2:08 PM EST
Hello Expert,
I wrapped my Arborvitae bush with burlap in late fall, as I do every fall to prevent deer from eating the lower leaves. Today, March 2nd, I unwrapped the burlap and the leaves that were wrapped have turned brown or are gone. I already picked up all the fallen leaves. What caused this? Will it come back? Do you recommend another method, so deer don’t eat the leaves in the winter? In the spring, summer and fall, I spray the leaves with deer repellent. Thank you.
Kent County Michigan
Expert Response
You used the best deterrent to prevent deer browsing. And generally speaking burlap will also help prevent winter burn.
When arborvitae turns brown in winter or early spring, the likely reason is winter burn. The combination of wind, sun, freezing temperatures, and lack of available water in winter can cause arborvitae foliage to turn brown because they are drying out. When an evergreen shrub can't draw water up through its root system to its leaves during periods when the ground is frozen (at which time any moisture in the soil becomes unavailable), those leaves, already beset by challenging conditions, give up their green color.
So how do you prevent arborvitae leaves from turning brown?
pruning. Hold off on pruning until well into the spring or even summer. Only time will tell as to whether your arborvitae
branches will recover from winter burn; there is not much you can do to reverse the damage that results in brown foliage.
Other actions you can take to increase the health of your shrubs:
1. Regularly monitor for signs of disease, pests, or other stress factors. Bagworms, scale insects, and other pests can cause browning. Signs such as frass, tunneling from boring insects, or
cankers oozing sap mean pests have infested the tree. Even if treated, the damage may be more than the arborvitae can withstand.
2. In spring, lightly apply a balanced, organic fertilizer.
3. Avoid trenching, driving, or digging near the root zone. This destroys roots and prevents the uptake of moisture.
Here are some indications that it's time to remove and replace your arborvitae:
Years of decline: Arborvitae that have been slowly declining for more than 2-3 years despite corrective care are often too damaged internally to recover.
Brittle, dead branches: If more than half the branches are brittle or snap easily, the tree's vascular system is too damaged to transport water and nutrients. Pruning out the dead material will only further stress the tree.
Rotten trunk: A soft, punky trunk covered in fungal fruiting structures indicates fungal root rot, a condition that progressively destroys the root system ultimately killing the arborvitae.
The average life span of some arborvitae is about 25 years. This represents the life span under ideal conditions. The shrub's life
can be shortened by salt contamination, deer depredation, disease or insect damage. Sometimes removal and replacement are the only viable options, especially if the tree is no longer attractive or serving its intended purpose.
When arborvitae turns brown in winter or early spring, the likely reason is winter burn. The combination of wind, sun, freezing temperatures, and lack of available water in winter can cause arborvitae foliage to turn brown because they are drying out. When an evergreen shrub can't draw water up through its root system to its leaves during periods when the ground is frozen (at which time any moisture in the soil becomes unavailable), those leaves, already beset by challenging conditions, give up their green color.
So how do you prevent arborvitae leaves from turning brown?
- Select a sheltered location at planting time. Avoid planting arborvitae on the south side of a wall (the sun can be an enemy in winter) or in an area exposed to high winds.
- Water in late fall to be sure the shrubs go into winter well hydrated before the ground freezes.
- Water during thaws. As you are aware, this past winter has been extremely mild...in many areas the ground never froze at all or froze only an inch or so down. Arbs like water. It's a good idea to water them in winter any time the ground is not frozen so the foliage doesn't dry out and brown. Any water you spray on the ground can permeate the loose soil and get down to the roots. The lack of snow cover this year also reduces the amount of moisture the roots would normally have available.
- Mulch over the root zone. Spread 2-3" of good-quality mulch around the skirt of the tree to hold in moisture, but keep it an inch or two away from the trunk to avoid access to insects and disease.
- Protect with tree wrap. You get an A for this one, but next time, do not wrap the tree so tightly that it suffers from compaction.
pruning. Hold off on pruning until well into the spring or even summer. Only time will tell as to whether your arborvitae
branches will recover from winter burn; there is not much you can do to reverse the damage that results in brown foliage.
Other actions you can take to increase the health of your shrubs:
1. Regularly monitor for signs of disease, pests, or other stress factors. Bagworms, scale insects, and other pests can cause browning. Signs such as frass, tunneling from boring insects, or
2. In spring, lightly apply a balanced, organic fertilizer.
3. Avoid trenching, driving, or digging near the root zone. This destroys roots and prevents the uptake of moisture.
Years of decline: Arborvitae that have been slowly declining for more than 2-3 years despite corrective care are often too damaged internally to recover.
Brittle, dead branches: If more than half the branches are brittle or snap easily, the tree's vascular system is too damaged to transport water and nutrients. Pruning out the dead material will only further stress the tree.
Rotten trunk: A soft, punky trunk covered in fungal fruiting structures indicates fungal root rot, a condition that progressively destroys the root system ultimately killing the arborvitae.
The average life span of some arborvitae is about 25 years. This represents the life span under ideal conditions. The shrub's life
can be shortened by salt contamination, deer depredation, disease or insect damage. Sometimes removal and replacement are the only viable options, especially if the tree is no longer attractive or serving its intended purpose.
