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Japanese Yew Turning Brown: 5 Common Causes

Japanese Yew Turning Brown: 5 Common Causes

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Japanese Yews are popular because they’re resilient and relatively drought-resistant. However, improper maintenance and various natural occurrences can turn your Japanese Yew brown, yellow, or light gray. Fortunately, there are more than enough solutions to these common problems.

Common causes of a Japanese Yew turning brown include harsh fertilizations or icing salts, sudden temperature changes, or poor soil nutrition. Inadequate drainage or a lack of hydration can also turn a Japanese Yew brown, as can root rot and low-end compost or mulch.

In this article, I’ll explain the most common reasons your Japanese Yew is turning brown and what you can do about it. 

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1. Fertilizers, Icing Salts, and Low-Quality Compost

According to Iowa State University, icing salts can cause significant damage and discoloration to Japanese Yews (source).

Furthermore, nitrate-heavy fertilizers can cause soil burning, leave browning, and dehydration. The same can happen if you add low-quality compost that’s loaded with harmful bacteria and fungal spores.

How To Fix

Here’s what you can do:

  • Avoid using icing salts around your Japanese Yew. If any granules get near the soil, sweep them away to prevent them from soaking into the soil.
  • Use low-nitrogen fertilizers. You can also stick to mulch and nutrient-rich compost if you want to avoid store-bought brands.
  • Make sure your compost bin is aerated, heated, and not too moist. Excessive amounts of moisture can encourage anaerobic decomposition, whereas not enough heat won’t let everything break down enough to be usable.

If your Japanese Yew already looks brown from icing salts, water the soil and wait until spring when the soil starts to heat up. Your plants will quickly turn green again once the salts go away.

Hydration, aeration, and a new layer of topsoil fix all three of these issues (after removing the source of the problem).

2. Rapid Temperature Fluctuations

One of the main reasons most plants turn brown or yellow is because they get too hot or cold. Japanese Yews are no different.

A sudden temperature drop can cause winter damage to the leaves, making them look brown. The discoloration occurs due to a lack of chlorophyll and water in the leaves. However, the Japanese Yew is very cold hardy and is unlikely to die due to the cold temperatures.

How To Fix

Unfortunately, you cannot do much to prevent winter damage to your Japanese Yew. The good news, however, is that these plants are durable and will more than likely withstand cold temperatures. All you have to do is ensure they have enough hydration and nutrients to last through the winter.

Additionally, remove large mounds of snow around the roots.

If your Japanese Yew is turning brown from too much heat, water it more often. The soil should never feel dry or dusty. Yew can water the leaves directly, but the vast majority of water is absorbed through the soil and into the roots. Consider using sun shades during triple-digit heat waves.

3. Inadequate Soil Nutrition

All plants need adequate soil nutrition, including minerals, carbon, oxygen, and nitrogen. Although too much nitrogen can cause problems, not enough will also have adverse effects. Most topsoil has a lot of nutrients, but various problems can limit the density, including:

  • Droughts
  • Excessive foot traffic
  • Pests
  • Weeds
  • Not enough water in the dirt
  • Compacted soil

How To Fix

If you think your Japanese Yew doesn’t have high-quality soil, follow these steps:

  1. Aerate the soil around the base of the yew with aeration boots or a manual aeration tool. This increases the airflow throughout the soil, allowing it to send more water and oxygen to the roots.
  2. Put a one-inch (2.5 cm) layer of nutrient-dense topsoil around the Japanese Yew’s roots. You can aerate it again if the topsoil seems a bit dense. Fluffy, airy topsoil is best.
  3. Use hose water to hydrate the soil rather than heavily-filtered water. Most garden hoses have a lot of necessary minerals, including magnesium and zinc.

You can try the MySoil Soil Test Kit (link to Amazon) to check the pH and nutrient-richness of the soil around your Japanese Yew. Simply scoop a bit of soil into the provided container, mail it to the company, and check the results on your smartphone.

A soil test is the most accurate method to determine what needs to be changed without any guesswork. 

4. Improper Drainage or Watering Cycle

Japanese Yews can’t have too much water sitting around their roots for too long. Not only does it lead to various bacterial issues, but it can also prevent the plant from absorbing enough nutrients.

On the other hand, the soil shouldn’t feel too dry. Your Japanese Yew should be watered if the soil has no water about two to four inches (5.08-10.16 cm) below the surface.

See our guide on The Signs Of Overwatering Plants.

How To Fix

Japanese Yews should have proper drainage. As mentioned above, soil aeration can make a big difference. If you don’t have aeration tools or boot attachments, you can use a shovel to mix the top layer of soil around the yew.

Poke your finger into the soil as low as it can go. If it’s still dry, there’s not enough water in it. If it’s spongy and mushy, there’s too much water. You can use small amounts of lime to dehydrate the soil. Remove the lime, then add hose water to prevent excessive root dryness.

5. Root Rot

Root rot is one of the most common reasons Japanese Yews turn brown. Root rot occurs when there is too much water in the soil or bacterial and fungal growth builds on the roots. Japanese Yews do not like wet roots (source).

How To Fix

Since root rot can’t be reversed, the only way to fix it is to clip the infected roots, stems, and leaves. The infected roots will look mushy, clumped, and potentially discolored. 

Once you’ve removed the infected areas, discard the old soil and replant the Japanese Yew in fresh soil to give the remaining roots a chance to grow healthy. 

Final Thoughts

Almost all Japanese Yews can be revitalized, regardless of why they’re turning brown or yellow.

Proper hydration, nutrition, airflow, and temperature maintenance all play significant roles in the development and success of these long-lasting plants. Remember to test the soil annually to know what needs to change, and don’t forget to use healthy, organic topsoil.

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Willie Moore
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