Although growing your own herbs or plants can be a really great experience, it can be equally frustrating when they do not grow as expected for what seems to be mysterious reasons. However, this is how your plant is warning you that something is amiss so you can intervene.
The top problems growing blueberries are discolored leaves, blueberry plants not growing, leaves curling, leaves drooping, and plants not producing or not flowering. The main solutions are enough water and sunlight, proper drainage, and acidic soil.
Throughout this article, you will learn the following about growing blueberries:
- Why the leaves of your plant might be falling off and how to fix it
- The causes for discolored (red, yellow, brown) leaves and what to do about it
- Why the leaves could be curling or drooping
- What the reason could be why your blueberry plant is not growing
- What to do when your plant is not producing or flowering
Blueberry Leaves Falling Off
Phytophthora Root Rot
Phytophthora root rot is the most common disease amongst blueberry plants and can cause serious damage to the plant or can even cause it to die. This fungal disease is most severe during spring or fall. You can recognize it by several symptoms such as defoliation (leaves that are falling off), chlorosis, and reddening leaves. I will delve deeper into the last two symptoms and what you can do about them later on in this article.
What Is Phytophthora Root Rot
Phytophthora cinnamomi is a fungus-like water mold that lives in the blueberry plant’s soil (amongst others) and causes Phytophthora root rot. The disease will slowly spread upwards towards the plant’s leaves, but it will initially be visible on the roots. After the roots and the stem are infected, you will notice that the leaves are yellowing or reddening. After this, the leaves will start to turn brown (leaf scorch), no new growth will happen, and leaves will start to die. The last-stage symptoms include defoliation and death of the plant.
How to Fix Phytophthora Root Rot
If you have a plant in the early stages of the disease, sustaining the plant could be possible. However, the disease can not be cured, so prevention is everything when it comes to phytophthora root rot. Here are a few important things:
- When you are purchasing new blueberry plants, sift through the roots and do not take the ones with dark grey or black roots.
- Avoid roots with a mushy-feeling.
- Before plant installation, make sure that the spot you choose for your plant(s) has good internal drainage as well as surface drainage.
- Make sure that no puddles of water collect around the plant(s).
- To prevent infections with new plants, using fungicides might be necessary—more about fungicides in the next paragraph.
Fungicides and What to Use Them For
In the process of preventing fungal diseases such as phytophthora root rot, fungicides are very effective. Before the plant is established, make sure that fungicides are applied twice a year. After the blueberries have flowered, apply fungicides again. Wait four weeks and then apply once more. If the drainage has been done properly, it will not be necessary to use the fungicides again.
Blueberry Leaves Turning Red
First of all, it is important to know that red leaves are very normal during cooler weather. However, if you notice the leaves of your blueberry plant(s) are turning red during the spring (while they are growing), it can indicate different issues. The leaves of your blueberry plant should have a green color during spring. If this applies to you, one of the following conditions can be the cause.
As I mentioned in the previous section of the article, reddening leaves could be caused by Phytophthora root rot, which in turn is caused by a type of fungus called phytophthora cinnamomi. How to prevent this disease can be read in the previous section.
- Phosphorus deficiency: If the pH level of your soil is above 5.2, it is no longer at the correct acidic level (ideally between 4.5 and 5), and the plant will no longer be able to absorb the proper amount of phosphorus, which can cause a phosphorus deficiency. To restore the acidic level of your soil, add one of the following things to it: Dried leaves, composted manure, peat moss, pine bark mulch, or coffee grounds.
- Magnesium deficiency: If magnesium is what your plant lacks, you will see this on the leaves; the leaves’ veins will turn yellow and then red. How can you fix this issue? Quite simple: Apply some Epsom salt in the soil, which will increase the magnesium level.
- Nutrient problem: Different nutrient issues have different causes. However, a lot of nutrient issues come from incorrect drainage. You can either fix the drainage or relocate the plant to a different area.
- Bacterial disease: Blueberry leaf scorch is a widespread bacterial disease amongst blueberries. It will prevent the water and nutrients from moving easily throughout the plant. The leaves will turn red, and eventually, the plant will die. You can prevent this disease by applying neonicotinoids. As soon as your plant is infected, you will have to remove it and replace it.
Blueberry Leaves Turning Brown
There are several reasons why your blueberry leaves could be turning brown. I am going to list all the possible reasons for you below:
- Water: Your plant is not getting enough water. Especially young plants are susceptible to this since their roots are still quite short, and the top part of the soil dries out the quickest. Young plants also have less shade so that the soil will dry out faster as well. More mature plants might take the water they need from the berries, which can cause the fruit to shrivel.
- Sun: Blueberries need at least 6 hours of full sun every day and some shade. If the plant does not get enough sunlight, it will not grow properly and die. Brown leaves could indicate that the plant is dying.
- Soil: Blueberries grow the best in acidic soil with preferably a pH-level of 5.0 but no more than 5.5. The key is to keep it moist but make sure that there is also proper drainage. Raising the plants above regular soil levels (about 12 to 18 in or 30 to 45 cm higher) can be very helpful. If the pH-level of the soil is too high, you can lower it by adding Ammonium Sulfate fertilizer, Ground Sulfur fertilizer, or sawdust to the soil.
Blueberry Leaves Turning Yellow
The leaves of your blueberry plant might be turning yellow because of something called chlorosis. If the soil’s pH level is too high (5.5 or higher), the leaves cannot produce enough chlorophyll. Chlorophyll is responsible for the green color that the leaves should have.
Blueberry Leaves Red Spots
The blueberry red ringspot virus causes the red spots you might have noticed on the leaves of your plant. When the leaves are pale green in the summer, the red spots might be the most noticeable.
You could also have noticed some red spots on the berries since the virus spreads quickly. Therefore, it is also essential that you remove all infected plants immediately after you have noticed the red spots to prevent other plants from getting infected as well.
Blueberry Leaves Curling
Several things could be the cause of the curling leaves on your blueberry plant:
- Lack of sunlight: As I mentioned previously, sunlight is essential for your blueberry plant. If you are noticing curling leaves on your plant, it might be an indication that it is not getting enough.
- Drought: Does your plant get enough water? Unmistakably, it is crucial for its survival. When the plant dries out, curling leaves could be a sign it is in dire need of some water.
- Insects: When insects settle on the leaves of your plant, they like to suck out the moisture and nutrients.
Blueberry Not Growing
It can be very disheartening when your blueberry plant is not growing while you are doing the best you can to make it thrive. However, there are some things to consider in order to figure out why your plant is not happy.
Like I mentioned a few times already, drought can be a real issue for your blueberry plant. If it is not growing, drought could be a very likely reason. As soon as the new plant starts to grow leaves, it will require more water. After spring, hot summer weather and the lack of water can dry out your young plant. If you notice that this is happening to your plant, take the plant out of the soil and replant it in summer or fall.
Another reason could be the soil’s pH levels, which I also already advised you about previously. Before establishing your blueberry plant, ensure that the soil’s pH level is between 4.5 and 5.5. Sandy soils do not hold water very well, and when all of the water that is there is absorbed, the plant will stop growing.
When a blueberry plant is not growing, what many people like to do is give the plant more fertilizer. Some even go as far as killing the plant with the enormous amount of fertilizer they give it. However, the best thing to do is to take the plants out of the soil in spring or fall and replant them.
Make sure to break up the root ball and then replant it. It is often the lack of water the plant has access to that makes it not grow. Young plants have small roots, and sometimes they cannot provide enough water to make themselves grow.
Blueberry Not Producing
When you decide to grow blueberry plants, the goal is to have some delicious home-grown berries eventually. When it is not happening, you want to find out what is going on.
Lack of Sunlight
I have said it before, and I will say it again: Blueberry plants need the sun! Lots of it (6 hours daily at least). This could be a solid reason why you do not see any berries.
Depending on the type of climate you are dealing with, your blueberry plant has different needs when it comes to wintertime. There are different variations of blueberry plants out there, and it depends on the type you have if they need winter dormancy to grow fruit the following spring. These plants need a certain amount of hours each winter, where the temperature drops under 45°F (7.22°C).
- North: If you are living in the Northern part of the country, you need a blueberry plant type that needs a lot of hours where the temperature is below 45°F (7.22°C). How many exactly depends on the type of plant you have. These plants usually need more than 800 hours of dormancy. Ideal blueberry types for the North are Rika, Jersey, Top Hat, Bluegold, or Bluecrop.
- South: Blueberry plants grown in the South have to be the type that needs less than 800 hours of dormancy. Examples of the type of blueberry you need in the South are Sunshine Blue, Jewel, Emerald, O’Neil, Misty, Southmoon, Sharpblue, Becky Blue, Brightwell, Climax, Vernon, Jubilee, Premier, Powder Blue, or Tifblue.
If you grow your blueberry plant near a pollenizer (a plant that produces pollen), it will definitely make your plant produce more berries. How necessary this depends on the type of blueberry plant you are dealing with. Most blueberry plants actually need more than one pollenizer, ideally three. This is called ‘cross-pollination.’ These two (or more) plants have to be within 100 feet (30.48 meters) of each other so that the same bees visit the same plants.
Blueberry Not Flowering
If your blueberry plant is not flowering, there are several things that you need to check. I have previously discussed all these specific elements, so I will just repeat them shortly below:
- Make sure your plant receives enough sun.
- Blueberry plants do not want wet roots; ensure good drainage.
- Ensure correct pH levels of the soil.
Blueberry Leaves Drooping
A cause for drooping or wilting leaves could be a temperature change. Most times, this will correct itself again when the temperature settles. It could also be a sign that the water and nutrients are not flowing well throughout the plant. Rodents could cause this; check the base to see if you can see any bite marks. Additionally, stress related to drought can also cause droopy leaves.
Blueberry Plant Has Aphids
It is very important to get rid of aphids (plant lice) when your plant is infested with them. These insects carry the scorch virus, which can cause critical produce loss. They are mostly present during the summer months, June and July, and they can be recognized by leaving a sticky honeydew. The insects live closely together and often infest young plants.
Why It Is Important to Get Rid of Them
There are several kinds of aphid species such as Aphis pomi, Illonia pepperi, Ericaphis spp. and others. They often take over a bush of blueberry plants and lay eggs on the leaves. When the eggs hatch, during spring, the troubles begin. As I said, aphids carry the scorch virus, and they suck out essential nutrients from the leaves, stems, and buds of the plant. The honeydew they leave behind can also possibly attract mold.
What to Do About Them
When spring comes around, check your plant(s) every week for these little creatures. Make sure to use a magnifying glass since they are very small and often live underneath the leaves. Make sure to remove all the weeds around the blueberry plant since aphids love to live there.
To extinguish aphids that have already settled on your plant, apply insecticidal soap immediately on the plant, and remember not to forget the bottom of the leaves. If you are still dealing with aphids after this, spray some chemical pesticides on the plant.
Frequently Asked Questions
- Should I fertilize my blueberry plant and if so, how often? Yes, you should fertilize your blueberry plant, preferably in early spring. New plants should be fertilized once in early spring and once in late spring. This will ensure that the fertilizer is completely absorbed during the plant’s growing time in the summer.
- Should my blueberry plant be pruned? Once a year, you should prune your blueberry plant. If it is your first time, make sure not to overdo it. Remove any old or brown leaves, broken or crossed branches.
Here is a rundown of the post:
- Make sure the soil has proper pH-levels (ideally between 4.2 and 5.0).
- Blueberry plants need a lot of sun (at least six hours a day).
- Blueberry plants need a fitting amount of water.
- Proper drainage is key for the survival of the plant.
- Using fungicides to prevent fungal diseases can be essential.
- Consider what type of blueberry plant will work for your climate.
Blueberry bushes can be productive for even up to 50 years. These are not high maintenance plants, but a myriad of problems can afflict them as they develop.
Avid gardeners encountering problems growing blueberry plants primarily find themselves facing either an insect-related issue and fungal diseases. Environmental stress factors do occur; however, these you can prevent by controlling the space where you grow the plants.
This article explains in more thorough detail the top diseases and pests that afflict blueberries and also possible solutions to fix them.
The flea beetle can jump like a common flea because of its overdeveloped rear legs. There are numerous species of flea beetles. The species that afflicts blueberries are oval-shaped with a coppery bronze color and shiny exterior. The adult is ¼ of an inch long while the larvae are about 3/8 inches in length.
This beetle leaves its pupae in the soil around the blueberry plants at least half an inch into the ground. The pupae are rarely visible, so they may be there for a while without your knowledge. In fact, the eggs of the blueberry flea beetle can be found at the base of the plant during the winter season.
Once the immature blueberries begin to develop in the spring, the eggs hatch into larvae, which start to feed on the foliage on the plants. This sustains the larvae as they grow into pupae. The pupae that bore into the soil in preparation of adulthood. When the adults emerge, they will feed on the blueberries until late summer, meaning they attack the plants during their most productive cycle.
An outbreak of flea beetles typically occurs in mechanically pruned fields.
To make sure you capture the problem with flea beetles before they wreak havoc on your crop, regularly monitor your fields throughout their early blooming period. If you notice defoliation, meaning the blueberry bush has no leaves, the best course of action is to spray the ground before the larvae metamorphose into adults. This allows you to catch most of the larvae which can’t escape like the adults.
Another approach is to burn the fields that have been affected to destroy the larvae as they hide in the soil.
The brown or black-gray moths that reproduce these fruit worms lay their eggs next to the calyx of the small green fruit from the blossoms. The larvae find their way into the ripening blueberries and turn the fruits blue prematurely. As they eat the developing fruits, they leave behind brown frass and a silky web.
You can monitor the male moths using pheromone traps to see the extent of infestation you have on your hands. Place the traps during bloom. You should also check the calyx of the plants for signs of the eggs.
If these interventions reveal the probability of fruit worm infestation, apply an insecticide that in the following chemical classes:
- Growth regulators
Cultural approaches to mitigate the problem also include clearing weeds and any form of trash around the plants. If they show up in your yard, you can manage them by handpicking the affected fruit and destroying them.
Not to be confused with the fruit worms, the blueberry maggots grow into adults that look like house flies but with black horizontal bands running across the wings. The life cycle of these pests is very rapid as their eggs hatch within three days, and the larvae quickly infest the berries.
You will notice the housefly resembling adults hovering on your berries for about two weeks as they mate and lay hundreds of eggs on an individual berry. The larvae infest the ripening fruit, and as they feed on the berry from inside, the fruit goes soft as it develops. The maggots eat the berry for up to three weeks, after which they drop to the ground.
Unfortunately, the pupae can lay dormant in the ground, not maturing for even up to three years.
Monitor your bushes for a few weeks before the blueberries begin to ripen, especially in early June. Use feed attractant infused sticky cards which you can buy from a feed store. These cards attract the flies and trap them. Check the cards over several weeks to monitor the first flies as they begin to mature.
Blueberry Bud Mites
These are tiny arthropods that feed on the inside of blueberry fruit buds. The mites reproduce rapidly and are white in color. Although they are only 1/125 inches long, they can cause widespread damage to the crop by killing the fruit buds.
The mites spend most of their life cycle inside the buds. The adult mites lay their eggs inside the scale of emerging buds. As soon as the eggs hatch, the nymphs begin eating the bud, and they reach maturity in 15 days. Because they mature so fast, you can get a full-blown infestation in a very short period. As their numbers grow, they move further into the center of the bud, making it impossible to salvage the crop.
Signs of blueberry mites include red, blistered scales on the buds. You will also notice misshapen leaves, flowers, and smaller than usual fruit.
Controlling a blueberry mite is very difficult using natural methods like introducing predatory organisms into the crop. The numbers are just too overwhelming for any natural enemy to eradicate. However, applying a miticide on the mites works effectively as long as you strictly follow the instructions on the label. That is because miticides lose their efficiency once the mites develop resistance against them.
Use miticides that have different active ingredients if you notice the mites are not responding to the treatment. Apply the miticide just after the harvest, before the buds form, if the mites are on the plants they have nowhere to hide.
Having an infestation of this pest results in the blueberry plant not producing fruit due to stunted growth. The sharp-nosed leafhopper is commonly referred to as SNLH, and it spreads phytoplasma to the bushes, causing stunt disease. They can be identified by their pointy heads and brown colored bodies.
Only the adults are the vectors of the disease, but both the adult and the nymph feed on the plant. After feeding, SNLHs retreat into the nearest woods during fall, where they overwinter and wait for the next feeding cycle.
Treatments for these pests should be focused on the perimeter of the blueberry fields because they come in from the woods. Killing them as they try to migrate into the field is more effective than trying to eradicate them when they are among the crop.
Thrips inhabit the blossoms of the blueberry plant where they suck the sap in the flowers. Both the larvae and the adult feed from the flower, reducing the quantity and quality of the blueberries harvested.
Also, thrips feed on the pollen in the flower, which causes fruit abortion. As the females lay their eggs, they cause scarring on the fruit in the process, making it unsightly. This reduces the marketability of the berries if they are commercial produce.
Use zip-lock bags and collect random flowers from different bushes in your field in each bag. If the bags yield between two and six thrips per flower, it is time to apply a wide-scale treatment. 2-6 may seem like a small number, but those are enough thrips to cause significant injury to an individual blueberry blossom.
Insecticide is the most popular treatment applied to blueberry bushes that are infested with thrips, but you must choose options that do not affect pollinators like bees. Spinosad is a safe option that is effective against thrips, but it is also friendly to bees.
Insecticidal soaps and narrow range horticultural oils are also safe for pollinators and other natural enemies of thrips. However, they are not as effective in controlling thrips.
These pests appear on the underside of leaves, around the buds and new shoots in the early weeks of spring. Check the bushes weekly for signs of aphids. They will occur as a cluster of little insects. Blueberry aphids suck the sap from the new shoots, buds, and leaves, leaving behind a mold causing honeydew substance that turns black. The honeydew also attracts blueberry ants.
The aphids also transmit an incurable disease known as the blueberry shoestring virus. Gardeners with high numbers of aphids report of their blueberry leaves turning red. This is a classic symptom of the blueberry shoestring virus afflicting the plants.
The pests inject the virus into the phloem of the plant as they feed, and it is transmitted to the rest of the plant. Sometimes the entire leaf doesn’t turn red or purple but only forms an oak leaf pattern along the veins of the leaves.
A steady stream of water on the plants will kill off the majority of aphids on the crop. Use insecticidal soap also to help kill them off. The good news is that aphids can be controlled using natural methods despite their numbers.
Also known as botryosphaeria stem canker, this disease is characterized by red-colored lesions on the stems of the blueberry bushes. The lesions are small at first, but with time they expand and grow, causing deep cracks to occur on the stem.
Stem canker is exceptionally challenging to treat because the fungus that causes it is not responsive to fungicide treatments. The only thing that may save your bushes is fast action on your part pruning six to eight inches off the stem at the lowest point of the disease. Burn the affected stems instead of burying.
The main course of action seasoned gardeners take to prevent and control stem canker is to pay very close attention to the blueberry shrubs they buy. Avoid buying any shrubs that show any presence of red lesions.
Phytophthora Root Rot
This is the most common disease afflicting blueberries. It is characterized by a blueberry not growing as healthy as the neighboring plants and having red leaves. When you look at the roots of the plant, they have lesions on the small feeder roots. As it progresses, the symptoms above the soil become more pronounced since the leaves quickly turn yellow. Blueberry leaves turning yellow typically send gardeners looking underground for phytophthora root rot.
The effects of this disease are more severe on young plants. As the root system becomes compromised, it is not uncommon to see necrosis on the margins of the leaves. A severe infection leads to the death of the plant. The rot appears as a brownish-black color on the roots, but as it progresses, it becomes red-brown and extends up the stem.
To prevent this disease, make sure that you don’t over irrigate the plants. The plants must not be in saturated soil for more than 48 hours. It is also best to plant your shrubs in raised soil beds rather than the ground. That is because the fungus that causes this disease is soil-borne and can lay dormant in the ground for a long time.
Also, avoid using previously used pots for repotting or propagation. You can also apply chemical treatments just before the plants’ roots peak to kill off the fungus.
Powdery mildew on the plant can be mistaken for the blueberry leaves turning white. But it is the powdery growth of the mildew that covers the leaves on the upper side. The result is a plant that suffers from stunted growth and has little to no yields.
This disease has also been associated with blueberry leaves curling as their formation becomes distorted by the infection. The infected leaves may also have red spots or rings on them, and they can begin to fall off prematurely.
You can eradicate the disease by applying foliar fungicides to the affected plants. Also, it is best to plant disease-resistant blueberry varieties to mitigate it.
Mummy berry is characterized by blueberry leaves turning pink and wilting. The pink-tinged leaves soon turn to a rosy brown color as the disease progresses. It is also not uncommon to see the blueberry leaves curling in plants affected by mummy berry.
The highest infection occurs on the new growth and typically at the base of the plant. You may notice the green bud begins to turn pink and wrinkle up instead of becoming purplish-blue and filling out. The infected berries shrivel and fall to the ground soon after.
The fungal structures settle on the floor of the orchard where they harden and resist decomposition allowing the fungal hyphae to overwinter. These structures, also known as mummies, hide under the fallen leaves and debris on the orchard floor.
When the flower buds break, the mummies settle on them, causing the primary infection, which results in the production of other spores known as conidia. Conidia appear as the gray fuzz on the infected parts of the plants.
There are several fungicides on the market that effectively combat mummy berry, but it is ideal to apply systemic fungicides and then protectant fungicides. Systemic fungicides are those that penetrate the plant and are effective against fungi from within the plant. These are typically used when the plants are young so that they are absorbed into the plant. Systemic fungicides suppress disease in plants even after the plants are infected.
Protectant fungicides, on the other hand, are applied before infection and then reapplied to the new growth of the plants in case the disease persists. They are also known as preventative fungicides, meaning they are only effective before the fungus enters the plant. If the plant is already showing symptoms, it is too late to use a protectant fungicide.
Unfortunately, blueberry cold tolerance is very low. They are affected by frost damage when they encounter low temperatures below 27°F (-3°C), especially in their early development. It is essential to control the environment as they grow, so keeping the temperatures above 20°F (-7°C) is ideal.
Frost damage is characterized by water-soaked berries that wither and fall off the plant. If the cold injury occurs on the pistil, only the stem will turn brown, and pollination will not take place on that flower. Ovules on blueberry plants typically are white and plump, but frost damage blackens them. Cold injuries may not damage the plant to the extent of causing them not to reproduce, but they will produce smaller fruit, which will appear late.
Eating a bowl of blueberries every day can protect you against food-related chronic health issues like diabetes, heart disease, and obesity. What is better than having several shrubs dotting your yard producing these life-saving berries for decades to come? However, you have to put in some work when it comes to caring for the plants including:
- Ensuring they grow in soil with the right nutritional balance
- Giving them systemic treatments in advance
- Clearing the area around them
- Cleaning the floor of the orchard
The good news is that blueberry plants are forgiving plants so they can bounce back if you catch the problem before it advances too far.