The wild blueberry fields of Maine are a true sight to behold! Gorgeous blueberries drip from plants left and right and invite families of all ages to enjoy their bounty. With such memories, it’s natural to want to replicate this paradise in any backyard garden. Blueberries have become so popular! Gardeners in the regions of the US that a few centuries ago couldn’t grow blueberry bushes now have access to recently created hybrids and cultivars that can weather milder winters or even no winter at all. However, in order to coax your blueberry bushes into putting out buckets of fruit, it’s essential to keep pruning blueberries every year.
With blueberries growing throughout the United States, there are several main types of blueberry bushes available. High-bush varieties are the most well known and widely planted variety. This type comes from the northeast United States and is most likely the parent plant of blueberries you find in the grocery store. Low bush varieties are more likely found growing wild in New England and Canada and less likely grown in home gardens. Rabbit-eye types are bushes that are better suited growing in the Southern US, or zones with milder winters. Regardless of what type you have, you’ll prune blueberries in pretty much the same way.
A newly planted blueberry bush is the one exception to the pruning rules you’ll find in this guide. During their first two years of growing, home growers need only make sure that the plant doesn’t produce fruit, and instead puts its energy into root and cane production. The best time for blueberries to begin fruit production is around year three, although the most productive time for the plant will arrive in years 8-10.
A young blueberry plant is best added to a garden with at least one other variety to cross-pollinate with. A savvy gardener will plant several and aim for blueberry bushes that produce during different seasons. As an adult eats on average two blueberry plants worth of blueberries a year, even more may be required.
Blueberries fruit on one-year-old wood. Unlike the raspberry or blackberry, a cane will produce for several years, with the largest harvests during a canes third to fifth years. Therefore, it’s important to remember that pruning blueberry bushes is very different from pruning other berries!
Blueberry bushes, as they age, will require pruning yearly. This is done generally in January, February or March when the worst of the summer snows have passed, and you can just start to make out flower buds on your bushes. The best time to prune is on a mild late winter, or early spring day with no chance of rain or heavy fog.
Why Prune Blueberries?
It may seem a bit tedious to prune blueberries, but it makes all of the difference in terms of fruit quality. Mature bushes especially benefit from pruning as old canes can suck up a lot of the plant’s energy without giving much in the way of fruit. Mature bushes often have 15-25 canes in them, with canes ranging in age from 1-6 years. Through proper pruning, you’ll be able to maintain roughly the same amount of canes throughout the plant’s life and prune out canes that have outlived their usefulness.
By removing tired older wood (over 6 years), and much of the twiggy annual growth, blueberry pruning increases the fruit quality and size of the blueberries produced. Additionally, by increasing airflow to the center of the plant, you reduce your risk of inviting pests and diseases into your bushes.
Harsh winter storms, a seasonal occurrence for people growing blueberries of the High-Bush varieties, may need to spend time inspecting their bushes for winter injury. These injuries can nurture diseases in early spring as life bounces back in warmer weather.
With proper pruning, you should be able to guide your blueberry towards a season with some pretty quality fruit!
When Should Blueberries Be Pruned?
Blueberry pruning begins at the end of winter and near the start of spring. When the blueberry bush has been bare for several months and weathered the worst of winter snows, get out your shears as this is the best time to start snipping away. As fresh cuts on blueberry bushes cannot tolerate extreme frost, make sure the chance of winter storms has completely passed.
It is during this period of time that it’s easiest to prune blueberries as the canes are easily distinguishable from one another. The supple, often red skin of the younger canes that are one to two years old stand out against the greying bark of the older canes. Healthy young canes, with the earliest signs of flower buds, appear on one-year-old growth showing where to expect berries the following year.
Pruning back some canes with flower buds on them may be difficult for the gardener, but it is necessary. 30-50% of the fruiting wood needs to be removed when you prune blueberries. However, make sure that not all of the fruiting wood is cut! It’s essential that you don’t go through and cut the tip off of every single branch. This is where you get your berries to grow.
Pruning Blueberries Step By Step
Even before you take the plunge and make your first snip, there are a few key rules to keep in mind when pruning blueberries. The very act of pruning can introduce the possibility of disease, both by transmitting diseases on dirty shears and by messy cuts. Before starting, sanitize your shears with rubbing alcohol to keep your berries safe. Additionally, make sure to use sharp shears that cut cleanly through without tearing at the cane.
The best time to prune is on a dry day. Give the blueberry plant a chance to begin healing itself after pruning before exposing it to rainfall, which can introduce diseases from rain spatter from the soil.
Identifying Fruit Buds and Vegetative Buds
Without leaves, your blueberry bushes can sometimes look like a pile of twigs just stuck in the ground all willy nilly! But take a few minutes and discover what you have in front of you! Take a closer look at the small branches, and look for two different types of buds that are just beginning to form. You should be able to see some larger buds in the shape of teardrops, and much smaller buds in the shape of small triangles that look almost thorny.
Teardrop buds go on to become flowers which after pollination turn into delicious blueberries. The triangular buds become the leaves and the following years laterally grown fruitwood. When deciding whether a branch on your blueberry plants is worth keeping, take into account the number of teardrop buds growing on a particular branch.
The oldest canes will have just a few of these tear drop buds, signaling that it’s time to remove them. The canes with the most buds, which are usually ones that are three years to five years old, will have the most fruit production. Be sure to leave those.
The First Cut
Regardless of the type of blueberry bush you’re growing, there are a few basic guidelines for pruning that all gardeners should follow. Every year, start by cutting out the deadwood, wood over 6 years old, crossed wood, and diseased wood. It’s easiest to identify these as dark brown or black branches with no signs of new growth.
Old wood is often grey, woody, and stiffer when you try to bend it. Sometimes, it even has moss growing on it. Remove these older canes to encourage the plant’s energy to go to the younger canes.
When pruning out deadwood, cut wood at an angle flush with the branch, or flat at ground level. Pruning cuts should be done at a 45-degree angle.
New vs. 6-Year-Old Growth
Blueberry canes produce berries on the same canes every year. While they only produce berries on new wood, a single cane will put out new growth on the same cane for many years. Each cane reaches the peak of production between years 3-5, and blueberry bushes overall reach peak production during years 8-10.
Mature bushes at any one time should have between 15-25 canes, but it’s best to have only 3-5 new canes a year. Cut back any excess new canes in your blueberry bushes, so that you only have 3-5 new canes for any one year.
Pruning for Shape and Airflow
Lastly, prune the center of a mature blueberry plant to allow for increased airflow to the center of the plant. Without sufficient airflow, pests can easily infest the bushes and decrease your chances of a healthy plant. Additionally, prune away small canes that grow close to the ground, are less than 1-2 feet tall, or stick out into an aisle or walkway. These are likely to become bent throughout the season, or have fruit that pulls the branch towards the ground inviting disease.
Prune out weak shoots, even if they have fruit buds on them. Remove old side growth in the form of twigs, the goal is to have blueberry fruits that don’t touch fruits from other branches.
Care of First-Year Plants
First and second-year blueberry bushes need much less aggressive pruning than do older plants. It’s important to keep young plants from setting fruit during their early life. Strip off flower buds before they have a chance to flower and set fruit. Don’t wait until too late in the season to do this as that energy needs to go to growing strong roots and canes.
Prune the canes to about half of their height, and remove twiggy growth. By doing this, the bush is encouraged to have a bushier and easier to manage shape. If the bush does well in its first year, go ahead and allow fruit production during its second year. Remember to fertilize and mulch as well! Your little bush needs a healthy start!
After pruning, apply fertilizer around your plants. They’ve just gotten a good haircut and will need some food to kick-start their growing season. While you don’t need to fertilize the same day as pruning, be sure to fertilize before their first leaves of spring appear.
As growing blueberries thrive in acidic soil, add a fertilizer that is acid specific. A preferred fertilizer among growers is Espoma Holly-Tone. Follow the directions for the type of fertilizer you’re going with as their roots are very sensitive to over-fertilization. Fertilizers are heavy in salts, and the roots can experience salt burn if you aren’t careful.
Lastly, apply a fresh layer of mulch around the base of the plant. Aim for 1-2 inches of mulch, but no more as the shallow roots of the blueberry plant can’t tolerate being buried too much. If there is already a layer of mulch present, push back the layer of mulch before fertilizing, then replace it once finished.
Frequently Asked Questions
Q: How do you prune an overgrown blueberry bush?
A: An overgrown blueberry bush is pruned in much the same way as a well cared for bush. One of the biggest differences lay in the percent of the bush that you need to cut back, and the lack of a bloom on your blueberry bushes the first year after pruning. Follow the same pruning rules – remove old canes, deadwood, crossed wood, and diseased wood. Encourage 3-5 new canes to grow, but aggressively cut back older canes to concentrate new growth in younger ones. Remove any scraggly or twiggy side growth and concentrate on giving room to sturdy fruiting canes to increase fruit production.
Q: Are used coffee grounds good for blueberry bushes?
A: While the myth of coffee grounds acidifying soil is pretty common, it’s just not true. The process of making coffee removes a lot of the acid from the coffee grounds, leaving a nitrogen-rich waste that is best added to a compost pile. Avoid adding coffee grounds directly to the soil around blueberry plants. Not only will it not acidify your soil, but it can stunt the roots of the plant by overwhelming it with nitrogen.