A reader reached out and asked why their blueberry plant’s leaves are turning brown. While I had an idea of what could be causing it, I wanted to do more research to be sure. Here’s what I found.

Blueberry bushes usually get brown leaves from under-watering or extreme heat. In some cases, improper nutrients and some pests and diseases can also cause it. For best results, water blueberry bushes when the top 2-4 inches of soil is dry, and apply 2 inches of compost and 4 inches of mulch.

So, while blueberry bushes get brown leaves for a few reasons, how can we tell which one is causing it, and from there—how can we fix it? Let’s take a closer look.

1. Under-Watered

brown-tipped leaves on a blueberry plant
A blueberry bush with brown tips usually means a lack of water or extreme heat (drought-stress)

The most common reason why blueberry plants get brown leaves is from drought-stress. Typically, this is from under-watering.

Symptoms of blueberry bushes that are under-watered include (usually in this order):

So, what’s the best way to water blueberry plants?

Only water blueberry plants when the top 2-4 inches of soil is dry. You can check this by pushing a finger 2-4 inches into the soil. The goal is to have soil moisture similar to a wrung-out sponge.

By checking the soil before you water blueberry plants, you’re preventing both under and over-watering.

To promote the best water retention, provide blueberry plants with 2 inches of compost and 4 inches of mulch. Reapply compost every 1-2 months and mulch every 3-6 months.

Compost provides valuable nutrients for the blueberry plant and increases the richness of the soil. For example, for every 1% increase in the soil’s richness, 1 acre of soil can hold an additional 20,000 gallons of water.

On the other hand, mulch dramatically reduces evaporation, regulates soil temperature, and prevents soil erosion. The best mulches for blueberry plants are leaves, bark, pine needles, and straw. Since blueberry plants evolved in forests, they’re used to plenty of mulch including fallen leaves and branches.

Tip: Avoid mulching blueberry plants if their soil has poor drainage. Once the soil is amended and is well-draining, begin applying mulch.

When applying compost and mulch, make sure to keep them at least 3 inches away from the blueberry’s stem mold can grow.

Generally, with poorly draining soils, potted blueberry plants can be repotted with fresh potting soil, while planted blueberries are a bit trickier. Typically, the best way is to provide at least 2 inches of compost and let it naturally work its way into the soil over time.

If you’re working with heavy clay soil, the clay’s poor drainage and alkalinity will likely lead to growth issues for the acid-loving blueberry bushes. In this case, it can be better to plant on mounds of potting soil instead of digging into the ground.

However, what if you check the soil and it dries out in a matter of a day or even hours?

2. Hot & Dry Weather

USDA hardiness zone map
Source: USDA

Blueberry bushes are native to cooler, more temperate climates. Because of this, they grow best in USDA hardiness zones 4-7. Typically, this is between -30ºF and 80ºF. So, if you’re located in zone 8 or higher, it could explain why your blueberry bush is getting brown leaves.

For example, when blueberry bushes get too hot, they begin to shed their leaves to ensure the rest of the plant survives. This starts with the leaves drooping or curling, turning brown, and dropping from the plant.

Tip: USDA Hardiness Zones are used by gardeners to see the average minimum temperature in their region. It’s a good way to see which plants grow best in your area. You can check your zone by using this map from the USDA.

While blueberries generally grow better in cooler climates, warmer varieties can be grown such as “Sunshine Blue”, “O’Neal”, and “Misty”.

Let’s take a look at some strategies to help your blueberry plant not overheat and dry out.

Hot Weather Tips

blueberry bush dying with a few green leaves

To help solve this, it’s helpful to know how blueberry bushes naturally keep themselves cool:

  1. Sending moisture from its roots to its leaves
  2. Exhaling moisture (transpiration)

You can think of transpiration similarly to how we sweat to keep ourselves cool.

So, you can successfully grow blueberry bushes in hotter and drier climates if you keep their soil moist (close to the moisture of a wrung-out sponge) and keep the area cooler and more humid.

Here are some best practices to grow blueberry bushes in hot and dry climates:

  • Compost: Apply 2 inches of compost to increase water retention
  • Mulch: Apply 4-12 inches of mulch to reduce evaporation and regulate soil temperature.
  • Humidifier: For indoor blueberry bushes, place a humidifier nearby. Similarly, keep the plant away from the central heat as this quickly dries out its leaves (I ran into this issue with my potted lemon tree).
  • Greenhouse or Mister: For outdoor blueberry bushes, grow in a controlled climate such as a greenhouse or use a mister to cool the air and increase humidity. Make sure it doesn’t get too hot in the greenhouse.
  • Plant Densely: You can increase humidity via transpiration by growing blueberry plants near other plants. The more plants nearby, the more shade and humidity. For example, using companion plants in a food forest is great for establishing a microclimate.

To learn more about microclimates, check out this cool video by Gardener Scott.

3. Improper Nutrients

Excess Nutrients

Excess nutrients (over-fertilizing) chemically burn the blueberry plant’s roots, causing stress and leading to poor growth as well as dropping leaves, flowers, and fruit. Normally, fast-release chemical fertilizers are the cause of over-fertilization as organic fertilizers and compost aren’t potent enough.

Lack of Nutrients

A lack of nutrients also stresses the plant, leading to similar conditions such as stunted growth and little to no flowers and fruit. This is commonly caused by poor soils, leaching, and other conditions such as improper pH.

Nutrient leaching occurs when the nutrients seep too far down into the soil, out of reach of the plant’s roots (beyond about 2-3 feet). This normally happens when soils have too much drainage or are over-watered. For example, sandy soils are notorious for their leaching properties.

Fortunately, most of these issues can be resolved by properly fertilizing blueberry plants.

The Best Way To Fertilize Blueberry Bushes

Our acid fertilizer we use for berry plants
The fertilizer we use and recommend for blueberry plants

The best way to fertilize blueberry bushes is to use an organic fertilizer and/or 2 inches of compost every 1-2 months. Apply the fertilizer three times, once in early spring, once before it fruits, and once after you harvest.

The three main nutrients for blueberry bushes (and most plants) are nitrogen, phosphorus, and potassium (NPK). Nitrogen is by far the most important (vital for root and canopy growth), but phosphorus and potassium are essential for flowering, fruiting, and the overall health of the plant.

The two main ways to fertilize your blueberry plant are with fertilizer or compost. If you choose a store-bought fertilizer, aim for one with a balanced NPK. For example, use a 10-10-10 NPK.

Chemical Fertilizer vs Organic Fertilizer vs Compost

I do recommend organic fertilizers and compost over chemical fertilizers. While chemical fertilizers have nutrients in quantity, they typically don’t have quality nutrients.

Even though chemical fertilizers might be sufficient over the short term, over the long term they often short-circuit the nutrient exchange between the plant and its beneficial soil life (such as mycorrhizal fungi). This leads to dry and dead soil (AKA dirt) and overall decreased plant health.

Mycorrhizal fungi promote many aspects of plant life, in particular improved nutrition, better growth, stress tolerance, and disease resistance.

Department of Biology, University of Fribourg, Switzerland

On the other hand, organic fertilizer and compost provide more than sufficient nutrients, increase water retention, and promote healthy soils. Many gardeners are even finding that compost is replacing their fertilizers.

Tip: Grow nitrogen-fixing companion plants such as seaberries and cover crops and use their clippings as mulch (chop and drop) to provide amazing nutrients to your blueberry plants.

If you’d like my recommendation for blueberry plant fertilizers, see my recommended fertilizer page.

Keep in mind that nutrients aren’t everything—blueberry plants also need a specific soil pH to properly absorb nutrients and thrive.

Soil pH

ph scale couch to homestead

Blueberry plants prefer a soil pH of 4.5-5.5. This is important because an acidic soil pH dissolves the nutrients in the soil, and makes them available to be absorbed by the plant’s finer roots.

Fourteen of the seventeen essential plant nutrients are obtained from the soil. Before a nutrient can be used by plants it must be dissolved in the soil solution. Most minerals and nutrients are more soluble or available in acid soils than in neutral or slightly alkaline soils.

Donald Bickelhaupt, SUNY College of Environmental Science and Forestry

Two good ways to check the soil’s pH are with pH strips or a pH meter. I prefer using a meter since they’re affordable and easy to use. To see which pH meter I use and recommend, check out my recommended tools page.

If you find your blueberry plant’s soil is too alkaline (above 5.5), provide acidic amendments such as peat moss, lime (ground limestone), and coffee grounds.

On the other hand, if your soil is acidic (under 4.5), provide alkaline amendments such as charcoal, wood ash, and lime.

4. Diseases

Root Rot

tomato plant with Phytophthora root and crown rot
A tomato plant with root rot

Root rot typically occurs from over-watered blueberry plants, or those with poor drainage (such as heavy clay soil).

Root rot kills off the blueberry bushes, which stresses the plant and causes symptoms such as fruit, flowers, and leaves yellowing, browning, and dropping. If not addressed, it leads to stunted growth or a dying blueberry plant.

You can typically tell if your blueberry plant has root rot if the soil is staying sopping wet and starts smelling like a swamp. Allowing the soil to dry out or repotting blueberry plants with fresh potting soil are the best ways to amend this disease.

There is no chemical control available for crown and root rot in the home garden. The most important control strategy is careful water management.

Clemson University Cooperative Extension Service

For example, I noticed my potted Kaffir lime tree had root rot as its soil smelled swampy and was staying wet for many days at a time. In this case, I repotted it with fresh potting soil, and the tree quickly recovered.

Bacterial Leaf Scorch

bacterial scorch on blueberry plants
Image Source: University of Georgia Extension

Bacterial leaf scorch is caused by the bacteria Xylella fastidiosa, and shows symptoms similar to leaves burning from under-watering, over-fertilizing, or root rot. Symptoms include yellow, brown, and sometimes black leaves.

This bacteria is thought to block the plant’s roots from receiving water and nutrients, eventually killing the plant. It’s commonly transferred via insects such as the sharpshooter, or leafhopper.

As far as varieties affected, the most common are southern highbush. Grapes, peaches, and plums are also affected by this disease. Warmer climates have higher rates of this disease as both the bugs and the bacteria survive better in warmer temperatures.

There’s no cure for leaf scorch. However, propagation management and some sprays have been found to help slow it.

“At this point, there are no chemical controls that actively kill the bacterium. However, it may be possible to slow or even break the disease cycle by vector management, killing the insects that transmit the bacterium.”

Final Thoughts

For the reader, they said once they started watering their blueberry plant when the soil dried out, its leaves stopped being brown (except for the occasional leaf).

Remember, if you aren’t sure which issue is affecting your blueberry plant, start with the least invasive option. For example, check its watering before digging it up or using sprays.



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