Full Japanese Blueberry Tree Timeline And Growth Rate

Japanese blueberry tree flowers

Though native to Japan and Asia, the Japanese blueberry tree is becoming a popular choice for landscapers and gardeners because of its beautiful evergreen foliage. If you’re unfamiliar with this tree and want to try growing it, you might be wondering about the growth rate of a Japanese blueberry tree.

Japanese blueberry trees have a moderate to slow growth rate. However, they follow a predictable timeline and can be germinated from a seed. They can take up to three years to get established but then require little maintenance. They will grow slowly to a fully mature height of about 40 to 60 feet!

The Japanese blueberry is often used as a privacy row because of its evergreen foliage and wide spreading canopy. They can also be used as a focal plant that attracts birds, butterflies, and pollinators. Keep reading as we go over how long it takes a Japanese blueberry to grow.

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An Introduction To The Japanese Blueberry

The Japanese blueberry does produce little, oblong-shaped, purple berries, but they are inedible to humans. Birds and other wildlife like to eat the berries, but the trees themselves are more for show than anything.

These slow-growing trees have broad, leathery leaves that some gardeners have said reminds them of Rhododendron trees.

Some of the leaves will turn a coppery-red color before they fall off, but they are usually replaced after a few weeks. The tree doesn’t lose all the leaves at a time, it replaces the oldest leaves a few at a time.

In the spring, the tree produces plenty of small, white flowers that butterflies and bees will enjoy. After that, the inedible berries start to grow, providing a stark coloration between green and red leaves, and the dark blue to purple berries.

These trees are hardy to warmer climates in the United States. They do best in USDA growth zones 8 to 11. They require very little care, are drought tolerant once they are established, and take well to pruning.

One drawback to note for the Japanese blueberry is they are a messy tree that may require some cleanup. Much like pine trees that drop needles all year long, this tree drops leaves all year long as they are constantly being replaced.

The North Carolina State Extension says that Japanese blueberry trees are relatively pest-free trees that adapt to many climates. They can be used as privacy screens, a windbreak, or alone as attractive specimens. The only problem most owners mention is the fruit and leaf litter that needs to be cleaned up often.

How Long Does It Take A Japanese Blueberry Tree To Grow?

Unless you are planting trees from seeds, the most time spent on growing your Japanese blueberry tree will be getting it established. After that, the only thing you’ll have to do is the occasional clean-up or mulching of the leaves and flowers that fall.

You can start your own Japanese blueberry trees either from seeds, cuttings, or saplings. If you’re growing these trees from seeds, keep in mind that it may take up to two years before they germinate.

On the road and unable to meet the time commitment of a Japanese blueberry right now? You could also try one of these other easy fruits to grow inside your van or RV if you’re a camper!

How To Grow Japanese Blueberry Trees From Seeds (Timeline)

If you are collecting seeds from an established tree, you need to gather them from the ground. The berries straight off the tree are not mature yet. Look for older berries that are dried up or have started shriveling.

Seeds that have been collected from the ground need to be cleaned off and have all the remaining fruit removed completely. You can also purchase Japanese blueberry seeds from some online sources, or possibly from your local nursery.

The First 24 Hours

Digging soil with shovel for planting

Once you have your seeds, the first thing to do is scarify them.

Scarifying seeds helps to break through the tough, protective outer covering of the seeds. Skipping this step adds months of waiting as you have to wait until the outer edge slowly breaks down.

Scarify The Seeds

There are a few different ways to break through the outer shell. Some people use chemicals such as acid to weaken the seed coat. This is often unnecessary for scarifying seeds at home.

You can use medium grit sandpaper, you can cut them with a pair of scissors, skate them across a metal file, or even use nail clippers.

To scarify seeds using sandpaper, you’ll need something around 100 to 180 grit. The smaller the number, the more coarse the sandpaper is. You don’t want something too coarse as you could break through quickly and damage the tender seed inside.

Alternatively, sandpaper that is too fine will take longer to get through the outer shell. 150 grit is ideal, but if you have something laying around that is close, go ahead and use that.

Take the seed, and scrape it across the sandpaper a few times until you have broken through the tough shell. Often you will see white, or some other light coloration when you’ve penetrated the outer coating.

The idea is to open the seed enough to let water and air inside the growing part of the seed so it will start the germination process. When the inner seed starts to grow, it will split the outer coating easily.

The process is the same with a metal file. Just examine the seed each time after you scrape it across the file. When you see the inner seed, you’ve properly scarified the seed.

If you are using scissors, or nail clippers, all you need to do is snip off a small section of the seed on either end. A sharp pair of scissors or a clean pair of nail clippers can make for easy work once you get the hang of it.

Be careful to just take a small section off. If you damage the inner seed too much, it won’t grow. All you want to do is open up the hard, outer shell.

Soak The Seeds

After scarification has taken place, you’ll want to soak the seeds for several hours. Soak them for 12 to 24 hours. Once they have soaked, drain the water and set the seeds on clean paper towels to remove excess moisture, then plant them.

While the seeds are soaking, prepare small pots for each of your seeds, or you can put two to three seeds in each pot and thin them out once they are growing. For the potting mixture, you’ll need well-draining soil. Gardening soil is too dense and will compact over time, and hold too much moisture for the seeds.

A mixture of one part quality potting soil and one part vermiculite, perlite, or sand will be ideal for Japanese blueberry seeds. Make sure your pots have drainage holes, then fill them with the potting mixture and water thoroughly in preparation for the seeds.

Make sure that the soil you’re using is acidic enough for your Japanese blueberry. Learn more about why acidic soil may be great for your tree!

Day Two: Germination

After you have soaked your seeds and have the pots ready and waiting, go ahead and place the seeds in the pots and cover them with a thin layer of soil. You only need about a half inch of soil covering them.

Next, give the seeds some water and put them in a warm area that gets plenty of sunlight. At least six hours worth. A sunroom or greenhouse is perfect, but if you don’t have either of those, a warm, sunny window will work just as well.

During the warmer days of spring and through the summer you can leave your pots outside, but you’ll have to water them more and keep squirrels and chipmunks out of them. They like to dig in the soft potting mix, and if they find the seeds, they’ll eat them.

Day Three And Beyond

Now you wait for the seeds to sprout. While waiting for them to poke their little leaves above the ground, keep the soil moist. You can do this by misting, or watering them lightly when the soil is dry to the touch.

When the pots are outside, and the days are hot and dry, potted plants can dry out very quickly. Check them every day when you have them outside. You may have to water them daily, or even twice a day while waiting for the seeds to germinate.

A little trick you can use to keep from having to water all the time, cover the pots with a clear plastic container or cut the bottom off a container such as a two-liter soda bottle or milk jug. Place it loosely over the pots to help keep the potting mix moist.

You don’t want a tight seal as there still needs to be an exchange of gasses or mold could occur. Just check the pots every few days and mist them as needed to keep the soil from completely drying out.

Remove the covering as soon as you see a sprout. Keeping the covering on while the seed is sprouting could cause the plant to get too hot, and could cook the tender sprout.

Even with scarification, seed germination could take a few months. Without scarification, you could be waiting up to two years before they finally show themselves. Be patient here and just keep the soil from getting too dry.

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Growing: From Seedling To Sapling

If you have grown your Japanese blueberries from seed, you can transplant them into individual containers when they are a few inches tall. While they are still small, it’s best to keep these trees in smaller pots until you plant them outside.

Smaller pots help to reduce root problems. For saplings under a year old, a quart-sized pot may be all you need. But if you notice the tree getting root bound, go ahead and transfer it to a bigger container.

For the first year, you can keep the saplings in a pot, but you’ll need to put them outside as much as possible so they harden. Water them regularly when the first inch or two of the soil is dry.

Adding an all-purpose fertilizer will help the growth for the first year. Look for fertilizer numbers similar to 10-10-10, and add the plant food once about every six months while they are in pots. Southern Ag All Purpose Granular Fertilizer 10-10-10 is a great all-purpose fertilizer that can be used wherever you need some even, extra feeding.

Japanese blueberries grow moderately fast for the first few years, then they slow down a lot. Once your tree is a few feet tall, go ahead and plant it in the permanent spot. They should grow three to five feet for the first few years, then slow down to one to two feet of growth per year.

The best time to plant Japanese blueberry trees outside is mid to late fall. Even though the tree is evergreen, it slows down growth during the colder winter months. During this time the tree shifts focus on the roots while the rest of the tree’s growth slows down.

If you don’t want to wait for seeds to sprout, consider purchasing small cuttings of Live Japanese Blueberry Trees.

Growing Japanese Blueberry Trees From Cuttings

Japanese blueberry trees grow well from cuttings. Start in spring when you can see new growth on the tree. Use clean, sharp pruning shears or a sharp knife, but a few stems that have about 8 inches of new growth on them.

Cut the stems at a 45-degree angle, remove all but the first two to four leaves, and soak them in clean water for an hour. You can dip them in Bontone II Rooting Powder for an added advantage. This rooting hormone powder helps speed root production which will give you more plants from your cuttings.

While the stems are soaking, prepare a mix of the potting medium that we went over for planting seeds. Water the soil so that it’s damp. After the cuttings have soaked and been dipped in the rooting hormone, plant them in the damp potting mix.

Keep the cuttings inside where they can get plenty of sunlight and keep the soil moist. After a few months, the cuttings should have a good set of roots on them. You’ll want to plant them outside, in their permanent home, in the fall.

What To Expect From Japanese Blueberry Tree Saplings

You might be able to purchase saplings from your nursery and skip the time spent trying to grow Japanese blueberries from seeds or cuttings. You’ll still need to spend time with these trees as they get established. Even when planting them from saplings, Japanese blueberries may still need two to three years of regular care.

Whether you have grown them from seeds or purchased already growing saplings, you’ll want to plant them in a sunny, or partially shady spot. These trees need at least six hours of sun and well-draining soil.

First Two Years

For the first two years, you’ll have to water your Japanese blueberry trees regularly. During times of drought and high temperatures, you may have to water them once a week. Adding a layer of mulch will help retain moisture so you don’t have to water them as often.

You want to keep the soil damp but not soggy. During the winter months, you can slow down the watering, and only water when the soil isn’t frozen.

Adding a small amount of fertilizer twice a year while these trees are getting established will help them stay strong and healthy.

Once established, these trees are drought tolerant, don’t need much fertilizer, and will grow well in slightly acidic or slightly alkaline soil. They’re not too picky. Just be sure to give them plenty of space as they can grow up to 60 feet tall and nearly 40 feet wide.

Japanese blueberries take well to pruning as well. You can keep them rather small—around 20 to 30 feet tall with regular pruning. Some people like to shape them in a conical, Christmas tree shape, but you can also trim them into round or oval shapes as well.

If you plan on letting them grow naturally without any pruning, you’ll need to space them about 40 to 50 feet apart.

Years Three And Beyond

Now that your Japanese blueberry trees are nice and established you can scale back the watering and fertilizing schedule. They are quite drought tolerant and will only need to be watered now during periods of extended drought. You also can stop fertilizing them.

By keeping a good layer of mulch around your trees, the mulch breaks down over time and releases organic matter into the soil for the trees. If you also mulch the leaves or let some of them naturally break down, they add to the organic matter, so there’s no need to add fertilizer.

Cleaning up after the leaves and flowers will be the most you need to do with Japanese blueberries after they have become well established unless you are pruning them to keep a certain shape.

You’ll want to start pruning these trees early. Getting them shaped the way you want is easier when they are young. Heavy, aggressive pruning can be tough on these trees so get them shaped before they are several years old.

Pruning can help to increase flower production and hold the shape you are looking for. This should be done once a year. Aim for late February or early March to do the pruning.

Remove any suckers and/or water sprouts as well as any unsightly limbs as needed. Suckers are vertical, quick-growing offshoots that grow along the base of the tree. They can take a lot of water and nutrients from the main tree.

The same goes for water sprouts. They are suckers that grow from the branches and are noticeable because they grow straight up. These need to be removed because they grow so fast that they can break easily and then cause illness for the tree if not trimmed quickly.

While pruning, remove any sickly-looking branches, branches that have no leaves, or ones that are rubbing on each other. With proper care, your Japanese blueberry trees should grow for at least 60 years.

According to The University of Florida, the canopy of Japanese blueberry trees benefits from yearly pruning, especially while the tree is still young. Other ways to keep the tree healthy are to provide plenty of sun, well-drained soil, and good airflow between the branches.

Keeping Your Japanese Blueberry Healthy

Aside from their beauty, one of the best things about Japanese blueberries is their health. With the right care, these trees rarely fall ill and have very few pest problems. The best way to keep trees from contracting afflictions or attracting insect pests is to keep them strong and healthy.

As we mentioned earlier, once they get established, the only real care they require is pruning and watering when Mother Nature is extending a weeks-long drought. Pruning at the correct time helps the tree heal itself and prevents problems.

The most common ailments these trees can get include sooty mold, leaf rust, and sunburn, but most times you won’t have to deal with any of these. You will want to learn more about these 6 Japanese blueberry tree problems (and how to fix them).

Wrapping It Up!

Japanese blueberries are a tolerant, easy, slow-growing, evergreen tree that can be used as a focal point in your garden or to add some privacy. They require a bit of care in the beginning but once they are set up you’ll have a care-free, attractive tree for many years.

They can grow to medium-large sized trees if left on their own, or you can even trim them to certain shapes and keep them small with regular pruning. However you plant them, the Japanese blueberry is sure to be a hit in your garden.

References

McDonald, M. B., & Khan, A. A. (1983). Acid scarification and protein synthesis during seed germination 1. Agronomy Journal75(1), 111–114.

Moore, M. R., et al. “First report of infecting Japanese blue berry tree in Florida, USA.” Journal of Nematology (2020).Wang, HeChun. “Growing performance of Japanese blueberry varieties in two forms of seedling.” Southwest China Journal of Agricultural Sciences 27.6 (2014): 2543-2547.

Wang, HeChun. “Screening of Japanese blueberry varieties suitable for open field cultivation of Dandong area.” Southwest China Journal of Agricultural Sciences 28.6 (2015): 2676-2680.

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