Are the arborvitae turning brown? What is the cause and how to fix the problem

I'm here to share my experience. If you buy something through our links, we may earn a commission.

If your arborvitae is turning brown, you may be wondering what is the cause and how to fix the problem. Arborvitae are a popular evergreen tree that can add beauty to any landscape. However, if they start to turn brown it can be concerning. In this blog post, we will discuss the possible causes of browning arborvitae and how to remedy the situation.

What is arborvitae?

What is arborvitae?
Photo from @americangardensllc

Arborvitae are a type of evergreen tree native to North America. They are popular with landscapers and homeowners because they are easy to care for and can add beauty to any area. Arborvitae can range in height from six feet to over eighty feet and, with proper care, can live for many decades. Arborvitae are often used to create hedges, in patio decorations, and in creating incredibly beautiful and intricate landscape patterns.

Properties of Arborvitae

Arborvitae, also known as Thuja, is a genus of evergreen trees belonging to the family Cupressaceae. There are five species in the genus, two of which grow in North America and three in East Asia. Such plants are very popular and can grow in zones 2 to 8. Arbovita can reach up to 25 feet in width, so it is a great option for creating shade in your yard area.

Arbovita can come in a variety of shapes: tuberous, conical, pyramidal, rounded, hanging, sharp and loose. Arbovita are equipped with dense, lacy needles that have a pleasant scent of pine needles. Their color can be richly emerald or golden. Arbovita grows quickly, 3 to 4 feet per year.

Why is arborvitae turning brown?

Seasonal needle drop

This is common in arborvitae and other evergreen trees and shrubs. The innermost needles that have grown in the previous year turn yellow or brown and fall off the plant. This is a normal seasonal process called “aging,” which primarily affects the oldest leaves. After these leaves are shed, new needle growth begins.

Seasonal needle drop
Photo from @provenwinnersdirect

This process can happen every year, but it can also happen once every two years. It will all depend on the type of arbovita itself. Keep in mind that before such brown needles fall from the branch, they may remain on it for a long time before renewal occurs.

Phytophthorosis

This is a common problem for arborvitae. If your tree is turning brown, it is probably caused by this disease. Phytophthorosis is caused by a fungus that affects the roots and bark of the tree. The best way to combat this disease is to treat the tree with a fungicide. You can also try pruning the affected areas. This is a manual method of treatment, but you can treat it with a special product.

Apex rot

Apex rot, caused by the fungus Phytopthora, is a common problem for arborvitae. The fungus attacks the tree through the roots and can cause the entire tree to turn brown and die. If you think your arborvitae has apical rot, look at the roots.

If they are brown and mushy, the disease is present in your plant. If this infection is not traced, it will quickly spread to the needles, which will start to turn brown and then die off. The problem starts because of insects and pathogens, so it is important to treat the plant with a special treatment for this kind of disease.

Cercosporosis

Cercosporosis
Photo from @lawn_irrigation_solutions

Cercosporosis is a common fungal disease affecting arborvitae. The disease is characterized by the appearance of brown or black spots on the leaves. The spots may be surrounded by a yellow halo. Cercosporosis is caused by a fungus called Cercospora. The fungus infects arborvitae leaves through wounds and the disease always starts on the lower branches, gradually spreading upward. This fungus usually affects eastern arborvitae species. The treatment is a treatment with Fuginicid.

Frosts

A very unusual reason why your arbovita may have brown needles. If you notice your arbovita developing brown needles during the winter or early spring, this indicates that the plant has received a winter burn. This is due to too low temperatures and strong cold winds. Even the winter sun worsens the situation by making the lack of water in the plant even worse, causing a winter burn to gradually develop.

The problem starts at the tips of the needles and gradually progresses to the center of the trunk.ย Protect the arbovita from winter scorch can be done with barriers of other frost-resistant plants, cover the arbovita with polyethylene on particularly cold days, you can put mulch around the roots of the plant.

Spider mites

Spider mites
Photo from @the_murdaugh_homestead

They are probably the number one cause of arborvitae turning brown. These pests are very small, but they can do a lot of damage to your trees. If you see cobwebs on the branches or leaves of an arborvitae, this is a sure sign of spider mites. You need to treat your tree with a product. Spider mites suck the sap from the needles, causing them to turn brown. The little parasites themselves can be red, black or brown.

Little water

Not enough water and too much sun are common causes of arborvitae turning brown. If you live in a region with a hot climate, be sure to water your arborvitae more often than usual. You can also try to provide the plant with shade during the hottest hours of the day. Arbovita requires 1 inch of water per week, which helps its growth and promotes its health.

Root problems

Photo from @patuxentnursery

There could be two problems here:

  • An immature root system – this happens when a young arbovita is planted in the soil. The root system is immature, so the needles will be brown instead of green. Watch your arbovitra for six months, if the color of the needles does not change to green, then the cause may be something else;
  • Root Injury – When transplanting or planting an arbovitra, its roots may be injured, causing them to not be able to pass enough water through their stem to the needles and the needles begin to suffer from dehydration and turn brown.
Nicolas Wayne

Gardening and lawn care enthusiast

Nicolaslawn
Add a comment