As a gardener, you know very well that keeping your plants healthy is part of having a beautiful garden!
One of the many things that can happen to plants is simply yellowing leaves.
While yellowing leaves on your Hinoki cypress can be a concern, there are solutions to revert the leaves back to green!
Healthy Hinoki Cypress
First, let’s define what Hinoki cypress trees actually look like.
Hinoki cypress trees are evergreen trees from Japan whose needles are a lush green.
They can grow to be very tall (up to about 40 feet). Hinoki cypress trees also produce beautiful and fragrant wood.
If we make a map of relevant USDA hardiness zones for Japan, Hinoki cypress grow well in zones 7-10.
Comparing the zones, that’s the west coast and the east coast, and everything below Utah to Kentucky.
Reasons Hinoki Cypress Turns Yellow
There may be many different reasons why your Hinoki cypress is showing yellowing.
For example, nutrient deficiencies, insect problems, or even drainage issues.
Let’s explore each one a little more thoroughly.
Transplanted
Hinoki cypress trees do not take to being dug up and moved very well at all.
The process is just too much of a shock for these trees, and if the root system has stopped taking water and nutrients up it will start to yellow.
If you transplanted a hinoki cypress tree in the recent past and are now noticing yellowing this is almost certainly the issue.
Transplanting young tree cypress trees is almost always preferred because they handle transplant better.
Nutrient Deficiency
A common cause for needle yellowing is a nutrient deficiency.
This is generally due to one of the elements needed for the tree’s success being low in the soil.
For example – iron is an essential nutrient for evergreens; if the soil is deficient in iron, then the needles will turn yellow.
Poor Drainage
Another possible issue might be poor drainage.
Hinoki cypresses like to keep their roots in moist soil (not wet).
If Hinoki cypress roots are sitting in water, they will rot, which can cause many issues, including yellowing needles.
Pests
Another source of possible injury to cypress trees can be pests.
For example, aphids are horrible pests that will feed on Hinoki cypress. If you see yellowing needles and small black bugs on a cypress tree, you can be confident that aphids are the cause of the injury.
Scales can also cause yellowing needles on Hinoki cypresses. Scales feed by sucking sap out of the tree, which results in a nutrient imbalance that presents itself as yellowing needles.
Fungal Disease
Lastly, another potential issue could be a fungal disease affecting your Hinoki cypress.
An example would be needle cast, which is due to the fungus Laricifomes officinalis.
This is a disease that occurs on the new growth that arises at the branch tips, where the needles turn yellow and then brown and ultimately drops off.
Proper Care for Hinoki Cypress
Now that we have reviewed a few of the causes of your Hinoki cypress’s yellowing, let’s talk about how to go about caring for the tree!
Soil
Hinoki cypresses require well-draining soil to prosper.
If the soil is lacking in sand, perlite, or organic material, moisture will build up in the root zone, leading to root rot if the soil is wet enough.
As a Gardener – You will want to incorporate more of these ingredients in to your soil before planting your Hinoki cypress.
Watering
It’s vital to keep up on watering these trees when they are young.
Once they are established, you can reduce the watering and provide an inch of water weekly during their growing season.
During periods of extreme heat, you may want to double up watering the Hinoki Cypress tree if the top inch of soil feels dry (i.e., water them more than once week).
Fertilizer
Barring any soil amendments from organic matter prior to planting the Hinoki cypress tree, fertilization should not be done.
However, if you notice the needles beginning to turn somewhat yellow, a light application of organic fertilizer – depending on the nitrogen content – can be applied.
Fertilization should only occur when there is new growth in the springtime.
Pest Control
In order to keep your Hinoki cypress safe from pest infestation, you can apply horticultural oil or neem oil.
These products will kill any pests that are currently on the tree and stopping pests from coming back.
You could also make your own insecticidal soap by mixing 1 cup of vegetable oil with 1 tablespoon of dish soap.
Mix the two with 1 gallon of water and spray the tree covering the entire plant. This mixture will prevent any aphids, whiteflies, or other pests from attacking the tree.
If you do find pests on your cypress, you can use rubbing alcohol to kill them.
This works the best—simply dip a cotton ball in the rubbing alcohol and apply to the pests. You may have to dip into the rubbing alcohol a few times and apply a few times to get rid of them all.
Final Thoughts
Let’s take some time to talk about some of the causes of your hinoki cypress turning yellow. The yellowing can be caused by nutrient deficiency, pest damage, a fungal disease or poor care and maintenance of the plant.
Don’t panic we are going to help you through this nightmare with this article!
While it is important to know how to treat a hinoki cypress turning yellow, it is just as important to know the cause of the yellowing for prevention.
Proper care of your hinoki cypress tree is all important for overall health of the tree. Keep the tree in good draining soil, and don’t forget water when young, especially!
Make sure to fertilize in spring, and watch for pests with horticultural or neem oil. Then your hinoki cypress will look its best!