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Communications at Oregon State University
Dave Brazelton: Growing blueberries requires
a lot of work and attention,
but no job is more important than proper pruning.
Hi, I'm Dave Brazelton.
On our farm and nursery here on Oregon's Willamette Valley,
we grow quite a few different varieties of blueberries.
Through the years, we've learned
the importance of proper pruning.
I'd like to take a little time to share
these techniques with you today.
It's harvest time,
and the crop looks pretty good.
One of the reasons it does is because of proper pruning
The primary objectives of pruning are to maintain good
food production, promote the growth of strong new wood,
and increase plant size.
To illustrate the effect that proper pruning
can have on production and new growth,
last winter we took three bushes of the same variety:
the first we didn't prune at all,
the second we pruned severely,
and the third we pruned in the normal manner.
By harvest time, you can easily see the results.
On the bush we didn't prune,
we see many small berries that ripen later.
And notice there is little new growth for future production
On the plant we pruned severely,
we see the berries are ripening earlier
and there's lots of new growth.
But the fruit load is low.
On the bush we pruned normally,
we've tried to reach a balance.
Here we've got good production of quality fruit,
and lots of new growth for next year's crop.
In this video, we are going to cover
the basics of plant growth,
pruning plants of different ages,
a few ways to increase pruning speed,
and pruning for machine harvest.
Before we get started,
let's take a look at the equipment you'll need:
good quality pruners, loppers, and gloves.
Some growers use a disinfectant to immerse
their pruners between each row or each bush
because this may decrease the spread of disease.
It's best to prune during the dormant season.
One of the main reasons why we prune blueberries
is to maximize the production of quality fruit
both for this year and the years following.
When I show a new pruner how to prune blueberries,
the first step is to show them the basics
of blueberry plant growth.
Of primary importance is being able
to distinguish between berry buds and leaf buds.
The berry buds are usually born
on the terminal ends of the laterals.
They're the large, fat buds here on the ends.
It's late winter now and they are exceptionally swollen.
Farther down you'll see the flat, scale-like leaf buds.
Blueberries originate their growth
from one-year-old canes, or rips.
These canes may originate from the base of the plant,
or higher up on the bush.
Most of the fruit is born on one-year laterals.
The best production comes from two-year wood.
This is your two-year wood.
The color is bright and shiny.
We'll go over that one more time.
One year's growth; the second year's growth.
Three-year wood is usually less productive.
The laterals are shorter, and they're less vigorous.
We call this "brushy" or "twiggy" growth,
and it will frequently be removed when we prune.
You can easily count this growth:
one year, two year, three year.
The color of this "twiggy" growth is blotchy and dull.
On our farm, we find it most effective
if we follow some basic steps to pruning.
First we remove the low growth.
Next we remove the brushy, twiggy, or diseased wood.
Next we'll thin out the fruiting laterals,
and finally, if needed, we'll shape the bush.
Let's review these steps for the various ages
of blueberry plantings.
This planting is going to bear for the fist time.
On young plantings, the first step of removing
the low growth can often be done simultaneously
with the fourth step of shaping the bush.
Here, this is last season's low growth,
and you'll see these short canes
that came up late in the season.
These canes aren't of sufficient size
to add to the structure of the bush,
so we will remove this entire piece.
Next we've got a fruit lobe here
generally that's below the knees.
If we allow this to fruit it will be down in the ground,
so we'll cut that out and also this low growth down here.
This is also too short for pickers to pick.
Remove that cane.
Now, with the low growth removed,
we're going to thin the berry buds.
Here on these main canes,
there's quite a few fruiting laterals.
If we allow them to fruit, the plant will over-bear,
decreasing the quality of the fruit and decreasing
the growth we get for the next year.
So, we're going to thin our fruit buds, here,
but in this instance, I'm going to head back
to keep the berries from weighting down onto the ground.
Then we'll thin a few more of the berry buds,
and the bush is finished.
Pruning young plants properly is critical for the
establishment of a well-shaped bush.
Not all plants are ready to bear
their first crop in the same year.
This plant hasn't made the cane
growth (here) and it's not as vigorous,
so we're going to basically remove
our low growth and remove the berry buds.
First, we'll cut the low growth;
Snip the top and then cut below the berry buds.
On this four-year-old bush,
we'll follow the same basic steps we had before.
First we'll remove the low growth,
and you can see this cane is lower and wider
than we want in the bush, so we'll remove it.
Next we'll want to remove the brushy and twiggy
growth and last season's bearing wood.
We do this by one fundamental principle
in blueberries and that's pruning back to new wood.
Notice the brushy, twiggy, non-vigorous wood.
We'll follow that back to new wood and we'll make our cut.
Now we'll continue to remove the brushy, twiggy growth.
This limb is crossing.
Now we'll thin our berry buds.
You can do this by breaking or by cutting.
And a little bit there.
A bit more there.
Final shaping of the bush, and the bush is finished.
Now bushes nearing maturity will
follow the same basic steps.
One fundamental difference is we're going to
remove some of the main canes,
either because they're too low and wide
or because they've lost their vigor.
On this particular bush there is quite
a bit of pruning to do, because there are so many low,
wide canes.
First we'll start by removing those.
Now that we've finished the low growth,
we're going to remove our brushy, diseased, or twiggy wood.
We'll do this, as in the younger plants,
by removing heading back to new growth.
If there is no new vigorous wood on the chute,
we'll remove the cane.
Now that we're finished removing
the twiggy and brushy growth,
we've got a cane here that is no longer
vigorous and we're going to remove it.
Next it's time to thin the fruit load on the bush,
if necessary.
On heavy producing varieties,
if we thin the fruit load on our branches,
this will retain the quality of the fruit.
Two-year-old wood can support between
four and eight laterals per branch.
The heavier the branch, the more laterals it can support.
We'll thin these laterals by either heading
the canes back or thinning the lower branches
and leaving the top laterals.
There are two ways to do this.
We can cut the top back or,
by breaking off these fine laterals,
we can leave the ones on top.
In this case,
the berries are up high where they're easy to pick
so we're going to strip the lower laterals.
That can be done by pruning or, what's easier,
is to take your gloved hand and strip up.
Here's an example of a two-year-old branch
that should be headed back.
If we allowed the end laterals to fruit,
they would be down on the ground.
So, we'll head back to the laterals farther down the cane.
On this two-year-old cane,
too many laterals were left so it over-bore.
There's very little new growth originating from the cane.
So this branch will be removed.
We'll continue to thin the fruit load by heading back
or stripping up wherever necessary around the bush.
As we finish thinning the fruit load,
we'll do the final shaping if necessary.
The finished bush has an open, upright vase shape.
This fully mature bush is a variety
that is very easy to prune.
It has a naturally upright,
open-growth habit, and the bright red wood color is very
easy to distinguish from the older blotchy wood.
All that's really needed to prune this bush
is to remove the old wood back to the new wood.
For plants that are to be hand-picked,
keep canopy height within easy picking distance.
This plant is finished.
On the other hand,
this variety is much more difficult to prune.
It has a spreading growth habit, and it's quite brushy.
Also, the wood color is difficult to distinguish.
The new wood is very similar in color
to the old blotchy wood.
We'll prune this bush using the same steps,
except, because of its size, we'll prune it in sections.
What we're going to try to do here is to prune it back
to that upright vase shape by removing some of the wide,
main canes on the outside.
We also have to pay attention to overall bush shape
and thinning the inside of the bush to
allow light penetration into the berries
and also watch our canopy height to get the size
of the canopy down to where it can be picked.
So let's start now and we'll remove
some of these lower, wider canes.
Okay, we've removed our low growth
in this section of the bush.
Now we'll go in and remove our brushy
and twiggy growth and thin our fruiting laterals.
I use both hands to work in the bush:
one with my pruners and the other
just breaking the branches, the smaller branches,
with my gloved hand.
This bush is just about finished,
however in shaping we want to make sure,
in mature bushes, that we open up the center
of the bush to allow light into the inside berries.
I'll remove these inside canes here for that purpose.
A bush of this size can be intimidating to prune,
but if we follow the four basic steps and prune
the bush in sections, it isn't too difficult.
If you need to increase your pruning speed,
you can do so by doing fewer main cuts at the base,
pruning more for shape,
and don't do as much fine pruning up higher on the bush.
This is going to remove some good wood
and leave some brushy and twiggy growth
but the same results are accomplished.
Here we're going to try to prune this
in approximately six cuts.
Normally we'd remove this brushy twiggy growth up on top,
but we've removed enough of the lower base cuts
and a high enough percentage of the wood
that the bush won't over-bear.
However the quality of some of this fruit
on the twiggy growth won't be as good.
Critical to increasing your speed,
is being able to visualize what that finished
bush will look like before you start pruning.
Some growers find it faster not to use their pruners.
They just break the canes and the twigs.
This can leave large wounds and that may
increase the chance of disease.
In some fields you may have bushes
that are lacking in vigor.
This particular bush has over-bore the previous year.
You can see where the fruit was last year,
lots of twiggy growth here.
Note there's no new canes coming up
from the base and very little, if any,
good vigorous growth.
If we follow our pruning steps and cut back to new wood,
you'll note there's very little new wood at all.
So we're going to prune this bush severely in order to
encourage new growth coming the next year.
For over-the-row machine harvesting,
the plantings are usually in solid hedge rows.
The crowns, or the base of the plant,
should be kept narrow to minimize fruit loss.
It's impossible to cover every pruning situation,
but hopefully we've helped you
to understand some of the basics and methods
behind blueberry pruning.
There's one final point to remember
when pruning time rolls around.
They say practice makes perfect and it
couldn't be more true when it comes to blueberry pruning.