“I live in zone 8 and have Blueberries. Do you prune Blueberries, and if so when?” Question from Lynn of Sacramento, California
Answer: Blueberry pruning is done to maintain crops as well as shrub shape and size. There are several rules when it comes to pruning blueberries. First, wait until shrubs are mature and fruit-bearing (at least five years old) before pruning for the first time. Next, like most fruit-producing shrubs, you need to wait until after their fruit has matured to prune. Blueberries produce flowers on old wood, so if you prune any later than post-fruit production, you will remove next year’s flowers. It is also essential to maintain strong fruiting wood, while removing weaker, spindly stems.
Four Blueberry Pruning Guidelines
Here are four guidelines to follow when pruning blueberries.
Prune just after berry harvest.
Maintain one strong fruiting cane (branch) for each year of growth, starting in the shrub’s fourth year.
Older canes can be replaced by stronger, newer fruiting canes after the shrubs have reaches 8-10 years.
Remove smaller, weaker, lateral branches to encourage stronger fruiting branches.
“I would like to fertilize some small blueberry plants I bought this year. I have your BLACK GOLD RHODODENDRON, AZALEA & EVERGREEN FERTILIZER, and I have some questions about its use because I don’t understand the instructions. It says “new plantings, 500ml per 1.5 m squared. Or 1.5 cups for every inch of diameter of the trunk. My plants are nowhere near 1-inch in diameter. I have a round pot, 15 inches diameter, and I have another plant, in a 14 X 20” rectangle. Also, doesn’t the depth matter as well when determining how much fertilizer to put in? Here are three more questions.
How do I know how much fertilizer to put in?
It says “measure 6 inches above the soil line”. What is the soil line? Then you say “the drip line”. What is the drip line?
The instructions say to mix the fertilizer in with the soil. How do you do that once the plant is already potted?”
Question from JM of Toronto, Canada
Answer: We are happy to answer your question about how to apply Black Gold Rhododendron, Azalea & Evergreen Fertilizer. Here are the answers to your three primary questions.
You will need to extrapolate from the guide suggestion: “Add 1.5 cups for every inch of diameter of the trunk.” For example, if the stem of your blueberry is approximately 1/2 inch in diameter, then work in 3/4 cup (175 mL) of fertilizer around the root zone of your blueberry. If it is smaller, extrapolate to add less.
The soil line is the soil layer that covers the roots, while the drip line is the diameter area of the plant crown. Please see the schematic below.
If you are adding fertilizer to a pot, then gently work it into the soil around the roots from the top. You do not need to work it in deeply. The fertilizer will make its way down to feed your plants every time you water.
“Do blueberries and strawberries need to be fertilized?” Question from Melanie of Holton, Michigan
Answer: Absolutely! Fertilization will encourage better growth, flowering, and fruit set. Each berry type has different needs when it comes to fertilizer.
Blueberries grow best in more acid soils (pH between 4.5 and 5.5) and require a specialty fertilizer formulated for acid-loving plants and/or berries. I generally fertilize in spring with a continuous-release fertilizer, but how you fertilize will depend on the product you choose. Follow the manufacturer’s application recommendations. There are many types of blueberry shrubs. To learn more, watch our video all about choosing and growing blueberries.
Strawberries like soils with a more neutral pH, and are less fussy. To encourage berry production, choose a specialty fertilizer formulated for strawberries or berries. There are many on the market. If your strawberries are June-bearing then I recommend fertilizing them in early spring and again later in the season, depending on what fertilizer you choose. If your strawberries are everbearing, then I would fertilize them with a continuous-release fertilizer in spring as well as a water-soluble fertilizer that will encourage them to produce berries through summer. For more information about growing strawberries watch this video.
Everyone who loves to grow their own food should grow their own blueberries. Blueberries are ideal for edible landscaping. They grow well in-ground or in containers. They’re bushy, attractive, and their leaves turn brilliant shades of orange, purple, and red in fall. Before adding them to your yard or garden, it’s good to know what types are available. You will be glad that you learned how to grow your own blueberries.
Blueberry Varieties Listed
Highbush Blueberries: ‘Blue Ray’ has extra-large-fruits early to mid-season, ‘Duke’ is high-yielding with upright shrubs, and ‘Elliott’ is a good late-producer.
Rabbiteye Blueberries: ‘Tifblue’ has large berries midseason and ‘Brightwell’ produces large clusters early to midseason.
Southern Highbush Blueberries: large-fruited ‘Cape Fear’, robust ‘Sharpblue’, and upright ‘Legacy’, which has very large, tasty fruits.
Designer Blueberries: The boxwood-like Blueberry Glaze® and cute, round Jellybean® have delicious fruit, tidy habits, and bright fall color (from Bushel & Berry).
“What would be a good fruit to try and grow in a cold climate?” Question from Chelsea of Alpena, Michigan
Answer: Lots of classic garden berries are very hardy and grow beautifully up north. Blackberries, blueberries, currants, gooseberries, strawberries, and raspberries are among them. If you are new to berry planting, I would start with lowbush blueberries because they are quick to set fruit, easy to maintain, and very hardy.
Blueberries (Vaccinium spp.) grow particularly well up north and are able to withstand climates far into Canada. Choose compact lowbush varieties that are easy to maintain. Two classics that are short, heavy-bearing, and flavorful are ‘Northblue‘ and ‘Northcountry‘. These would look right at home along the edge of a sunny patio or even in containers. Speaking of container berries, the new designer lowbush blueberries in the Bushel and Berry® Series are also excellent varieties to try. (In fact, all of there berries are quite hardy and low-care). Of these, I think Blueberry Glaze® is especially beautiful because of its tidy, boxwood-like habit and tasty berries.
Alpena, Michigan is blueberry country, so you should not have trouble growing them, but you should still know the basics. Plant your berries in full to partial sun. The key to happy blueberries is getting their soil right; they like well-drained, acid soils with a pH between 4.5 and 5.5. When soils are too alkaline (have a higher pH) blueberry plants cannot access necessary nutrients, and their leaves start to turn yellow. To keep this from happening, amend the soil with Canadian Sphagnum Peat Moss at planting time and feed with a fertilizer formulated for acid-loving crops, like blueberries. Water your berries if rain has been infrequent and the soil starts to become dry. If you start with robust, good-sized plants this spring you will have berries by summer.
If you are interested in growing other berries on a small-scale, read our article about the best fruits for container gardening. If you are interested in growing strawberries, watch the video below.
“My blueberry plants have yellow leaves. Why is this happening and what can I do?” -Question from Emily of Columbus, Ohio
ANSWER: Your blueberries have chlorosis. This is caused by a soil pH problem. Blueberries like acid soils between 4.5 and 5.5. When soils are too alkaline (have a higher pH) blueberry plants cannot access necessary nutrients, and their leaves start to turn yellow. Thankfully, this problem is easy to fix.
First, it helps to determine the pH of your soil. Take a soil sample to your local Ohio State University Extension Service (click here for instructions). Once you get the results, you will know how much you need to lower your soil’s pH for your berries.
You can lower soil pH by amending with Canadian Sphagnum Peat Moss and adding a soil acidifying fertilizer around the base of the plants. Aluminum sulfate will quickly lower soil pH; there are also other brands of soil acidifiers and acid fertilizers specialized for crops like blueberries. Follow the instructions on the packaging to adjust the pH around your blueberries, and they should bounce back in no time!
Forget that blueberries (Vaccinium spp.) are just a crop for the far north because that’s changed. Modern selection and breeding have resulted in a range of hybrids and varieties that extend blueberries into almost every growing zone. What makes this such a great opportunity is that blueberries are produced on shrubs. That means they will fit right into any existing ornamental landscape while producing annual crops of berries.
Best Warm-Climate Blueberries
Choose from two blueberry types for warmer climates: drought-tolerant rabbiteye hybrids (Vaccinium ashei hybrids, Zones 7-9, 10-12′), and southern highbush hybrids (Vaccinium corymbosum x V. darrowii x V. ashei hybrids, Zones 7-10, 6′). In the Southwest and California, try rabbiteyes such as ‘Bluebelle’, ‘Southland’, and ‘Tifblue’. In Northwest California and the American South, where there’s higher rainfall, try the southern highbush varieties ‘Jubilee’, ‘Misty’, ‘O’Neal’, and ‘Southmoon’.
While many cultivated blueberries are self-fertile, pollination and yields are increased by growing different varieties with the same bloom times. Blueberries are pollinated by native bees and honeybees, so it also pays to plant extra spring-blooming bee plants to increase pollinator density at blueberry flowering time.
Like rhododendrons and azaleas, blueberries are ericaceous plants that originate from woodland environments with well-drained, acid (pH 4.0 to 5.0), sandy loam with a shallow layer of organic matter, called the “duff layer”, which lies just below the tree litter. This is why they grow best with some shade and have wide, shallow root systems that favor low pH soils. Even if you get a blueberry stipulated for warmer climates, they still require this universal soil condition.
This makes blueberries the perfect edible plant for those properties with good soil drainage and high tree canopies. While most other edibles need direct sun, blueberries do exceptionally well under tall shade trees that provide substantial filtered light and morning sun exposure.
Choose an upland site with low soil moisture and good drainage—sandy to average loam soils are best. If the soil quality is not suitable, be it too alkaline or too rich in clay, be prepared to amend your soil.
Peat moss is the best source of organic matter for acid-loving plants like blueberries. Dig a hole three times as wide as it is deep and mix the native soil with 50% Black Gold Canadian Sphagnum Peat Moss. Then add a high-acid fertilizer contain ammonium sulfate or sulfur-coated urea (apply using package recommendations) and backfill. Finish by adding a 3″ mulching layer of Black Gold Garden Compost Blend to help keep root zones cool and moist. Providing an organic-rich, fertile layer of acid soil around the new plant stimulates rapid lateral root growth and helps protect against periodic heat and drought.
Blueberries also grow well in large patio containers filled with OMRI Listed® Black Gold Waterhold Cocoblend Potting Soil, which is approved for organic gardening and ideal for keeping roots from drying out in the summer months without using excess water.
Because blueberries fruit on newer stems, refrain from pruning them in the first couple of years to help them become better established. [Click here to learn how to prune established blueberry bushes.] In fact, it is best to strip off the first-year flowers and blueberries to help plants invest all their early growth towards sturdy roots and stems.
Blueberries are long-lived shrubs that will bring yields to your landscape for years to come. They will also allow you and your family to enjoy the bounty of home-grown organic fruit in just about any landscape or garden.