Arborvitae care - Ask Extension
We have arborvitae's that are not looking too good. We put slow release fertilizer stakes in. Now we want to make sure we water enough. Where should...
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Arborvitae care #794909
Asked June 08, 2022, 2:22 PM EDT
We have arborvitae's that are not looking too good. We put slow release fertilizer stakes in. Now we want to make sure we water enough. Where should a rain gauge be placed - under the tree or outside of the tree line? How do you recommend watering? I see so much contradicting info. online.
Thank you.
Ramsey County Minnesota
Expert Response
There are two common reasons why arborvitae foliage turns brown. Winter injury on arborvitae often occurs in MN. In winter, arborvitae dry out when the needles lose water faster than they can take it up when the soil is frozen. Desiccation can cause arborvitae to get winter burn. If the foliage is buried under snow, that area is protected. But unprotected needles will suffer from winter burn turn brown.
If your arborvitae has browning of the inner foliage in fall then the problem is probably due to seasonal needle drop. In fall,the innermost needles gradually turn yellow or brown and drop to the ground. Environmental stresses, such as drought or windy sites can cause greater than normal loss of arborvitae foliage. The needles on the outer growth remain green on healthy trees. Most MN landscapes, healthy arborvitae do not require much fertilizer. The best time to fertilize your evergreens is before new growth expands, around early April in Minnesota, up to about mid-July. A soil test will provide a base of information about your soil and the fertilizer analysis you will need for your plants.Trees absorb nutrients applied to adjacent turf grass. Fertilizer is not the solution for most landscape problems. Never fertilize a drought-stressed plant. If you need to fertilize your arborvitae it is better to evenly broadcast the fertilizer under the entire canopy of the tree. Keep your arborvitae healthy by mulching the soil surface under their branches and slightly beyond. A 3-4 inch mulch doughnut shaped ring should start few inches out from the trunk and continue out beyond the canopy. Slowly water the arborvitae in the area from the trunk to slightly beyond the canopy. Since roots grow deep, trees prefer a deep watering less often versus watering frequently and only wetting the surface of the soil. Dig in the soil with your finger and feel how moist the soil is. If it’s dry, then it’s time to water, if it feels wet, hold off on watering for a couple of days. Excess watering is just as bad as under watering.Yjr following site will help you care for your tree.
If your arborvitae has browning of the inner foliage in fall then the problem is probably due to seasonal needle drop. In fall,the innermost needles gradually turn yellow or brown and drop to the ground. Environmental stresses, such as drought or windy sites can cause greater than normal loss of arborvitae foliage. The needles on the outer growth remain green on healthy trees. Most MN landscapes, healthy arborvitae do not require much fertilizer. The best time to fertilize your evergreens is before new growth expands, around early April in Minnesota, up to about mid-July. A soil test will provide a base of information about your soil and the fertilizer analysis you will need for your plants.Trees absorb nutrients applied to adjacent turf grass. Fertilizer is not the solution for most landscape problems. Never fertilize a drought-stressed plant. If you need to fertilize your arborvitae it is better to evenly broadcast the fertilizer under the entire canopy of the tree. Keep your arborvitae healthy by mulching the soil surface under their branches and slightly beyond. A 3-4 inch mulch doughnut shaped ring should start few inches out from the trunk and continue out beyond the canopy. Slowly water the arborvitae in the area from the trunk to slightly beyond the canopy. Since roots grow deep, trees prefer a deep watering less often versus watering frequently and only wetting the surface of the soil. Dig in the soil with your finger and feel how moist the soil is. If it’s dry, then it’s time to water, if it feels wet, hold off on watering for a couple of days. Excess watering is just as bad as under watering.Yjr following site will help you care for your tree.
https://apps.extension.umn.edu/garden/diagnose/plant/evergreen/arborvitae/
https://extension.psu.edu/arborvitae-diseases
https://extension.umn.edu/trees-and-shrubs/fertilizing-evergreens#mulching-evergreen-trees-and-shrubs-1340014
