Blueberry Site Preparation and Establishment

Blueberry Site Preparation and Establishment


[music] Hello everyone Bill Cline here with
North Carolina State University this session will cover blueberry site
preparation and establishment. We’ll also talk a little bit about irrigation and
pruning as it relates to establishment this quote comes from Gerard Krewer, a
retired horticulturist with the University of Georgia if anyone knows
how to grow a blueberry it’s Gerard, but he was explaining to Rabbiteye growers
how hard it was to grow southern highbush blueberries and really love
this quote the southern High Bush is a plant looking for a place to die, so this
should inform you that there are differences in species and how well they
grow and how difficult they are to grow and we’ll get into some of that as we go
through this talk so what makes a good blueberry site these are two sites in
North Carolina one in the high mountains the other in the coastal plain Ashe
County North Carolina and Bladen County in the coastal plain and what do they
have in common? The common features and successful blueberry sites are good
drainage soil aeration low pH organic matter and water so the pH should be
around 4.5 it’s the middle of the range organic matter you’d like to see above
3% drainage really critical and really something that has to be addressed
before the bushes are ever planted and most sites in most years during
establishment will will require irrigation blueberries have only been
cultivated for about a hundred years they were domesticated around 1916 and
some of the oldest states that that produced blueberries have unique soils
where they perform quite well so in North Carolina these are our organic
sands with the high organic matter content and a water table really near
the surface now as a county extension agent advising people on how to grow
blueberries this is very often not the situation that you will encounter so in
order to emulate this you would be adding organic matter to the soil any
irrigation and embedding the roads to improve route
aeration the blueberry root system is about as wide as the top part of the
plant not much wider a fibrous mat of roots underneath the bush and the depth
of routing is dependent on how well aerated the soil is so the better job
you do prepping the site the better root system you will have here we see two
very different soils in North Carolina the the picture on the left is Carolina
Bay’s soil still in the soil core just as it was pulled out of the ground high
humic matter percentage pH is low and internal drainage is really good it’s
still a sand-based soil on the right you see a red clay that has low humic matter
the pH is low which is good but internal drainage is very poor so handle these
soils very differently in terms of site prep from a fertility standpoint the
Pamlico muck as you look at the bottom line on this soil test report the humic
matter is at 10 plus percent pH 3.7 and if you look in the the red circle the
fertility recommendations are for zero lime 30 to 60 pounds of nitrogen
per acre 50 to 70 pounds of phosphorus and a little bit of potassium so on
these soils are very often phosphorous is the most limiting factor if we
compare the basal to a typical Piedmont soil sample in North Carolina you look
at the bottom line here on the soil test result the first number of humic matter
is 0.66 percent so less than one percent so this site would definitely need to be
mulched for blueberry the pH is 5 so that’s pretty good if you look at the
fertilizer recommendation in the red circle just nitrogen by the time the
second year comes around so very different
soil tests from the Carolina Bay’s soil soil testing is really important because
that’s what you base your fertilizer applications on if you can see from
those two soils very different recommendations
based on the soils generally blueberries are not going to take up and you
fertilizer until they start to leaf out in spring and most of our fertilizer if
needed is applied early early in the season and you want to end by mid to
late summer to the allow the plants time to harden off before winter so often
nitrogen is the only thing that’s needed the nitrogen need is going to increase
with the plant age a couple of good sources a urea or ammonium sulfate these
are some of the references that I’ve found useful over the years for
blueberry fertility in addition to our own state recommendations there’s a
highbush blueberry production guide on the web there’s some good information
out of Oregon State a lot of work done there and a nice article in Hort
technology in 2015 that that is helpful as well if you’d like to do some reading
on some of the basis for these recommendations but again your own soil
test results are the ultimate guide for what you would like to do one great way
to evaluate a site for blueberry production is to look up the soil type
on soil maps and we used to carry around a book for every County but now the web
soil survey is available just want to make sure everyone’s aware of this
website so you can map sites by by address or find them with the satellite
imagery and just a really good resource for for evaluating a site for any sort
of crop production on the upland sites the way you modify a site for blueberry
production is to add add bark mulch to give the plant a substrate in which the
roots to lower the pH and improve the drainage the finished height on this
field will be with beds 12 to 18 inches higher than the row middles drainage is
critical for aeration in the root zone and the drains have to be maintained for
the life of the planting when amending the soil it’s important
to distinguish between bark or wood chips the pine bark from the outer part
of the tree is a good soil amendment for blueberries can be mixed into the soil
prior to planting wood chips are not a good soil amendment because they tie up
too much nitrogen so the white interior part of the tree does not work well as a
soil amendment unless it’s decayed it works really well on the surface as a
mulch but not mixed into the soil at this point I’d like to review the basics
of establishment and then take a look at some images later of established sites
first thing you’d like to do is to select a well-drained site in full Sun
they’d like to avoid clay soils if possible and you’d like to acidify the
soil if needed to a pH between 4 and 5 a lot of soils in the southeast if they
haven’t been limed will be pretty close to this initially best way to find this
out is to have your soil tested and once you have that you’ll know what the humic
matter percent is and also the pH and you can adjust the fertility levels
according to those results after that you want to make sure you purchase the
correct species and cultivars for your soil type and location in a lot of
instances this will be rabbit eye blueberries rather than southern high
bozo or northern eye bush most sites will need to add acidifying organic
matter so peat moss pine bark or aged sawdust and almost always need to mound
the amended soil to form raised the beds unless the site is sloping and convex
just really will benefit in most cases from from raised beds continuing here
with the basics we like to plant dormant bushes in
raised beds or rows usually in late winter so that’s going to be February or
March I typically prune the bushes at planting
to keep only 3 or 4 upright chutes and to reduce the height by 1/2 to 2/3 so
that’s a pretty severe printing even if you do not prune it planting you
still want to make sure to remove the flower buds
you can either prune these off or just strip the flowers off once the bushes
begin to bloom but it’s really critical that you prevent fruit production in the
first year after planting you want to provide water most most locations in
most years you’ll have to have irrigation to get good survival you’d
like to maintain a weed and a grass free zone around each plant the blueberries
do not compete well with weeds or grass especially young bushes and you can
apply a layer of surface mulch now this can be pine bark on needles wood chips
or a plastic or woven plastic weed mat fabric some additional considerations
before you plant depending on what you find when you dig holes in the field and
evaluate the the drainage you may find that deep ploughing is needed prior to
forming the beds weed control and pH adjustment and mulch may take a year or
more to get right so you have an opportunity before the bushes are there
to really do some some pretty stringent weed control and much more difficult to
do once the plants are in place if sulfur is needed for pH lowering
needs to be applied at least a year ahead of time
sulfur lowers pH through a biological process not a not a chemical process of
bacteria have to break down the sulfur and that takes time after a year you
retest and determine whether the pH has been lowered enough and then you can
complain drainage and raised beds are best addressed before planting it’s just
really hard to improve drainage once the bushes are in place and the last point
their row orientation I hear folks say should I plant east to west or north to
south and I really think row orientation should optimize drainage I think
drainage is a lot more important than orienting for sunlight
at planting time I like to have the bed area prepared so that you can plant with
your bare hands if you’re really out there chopping around with a shovel it’s
not it’s not fluffy enough it’s not well aerated enough yet for planting would
encourage you to start with some clean plant materials so be careful where the
or the plants come from get them from a clean and true to type source tissue
culture plants that have been virus indexed are becoming more available and
if you can find those I would encourage you to to pursue them we generally plant
extra you can double set some plants so if you’re on a 4 foot spacing maybe
plant part of a row on a 2 foot spacing just to have some extra plants growing
in the field that will be the same age as as the rest and then when the plant
dies you can reset it with one of the double sets really like the idea of a
weed matting or plastic for previously planted areas where weed pressure may be
high and again irrigation is just a Center this is a planting in coastal
South Carolina the site was amended prior to planting raised beds no plastic
on the surface but wood chip mulch as the surface mulch this field is in
coastal North Carolina and it’s a pick-your-own pine bark amended these
are southern highbush blueberries and bedded and with black plastic on the
surface this field is in the eastern Piedmont of North Carolina
these are rabbit eye blueberries this is year to say February there’s a minted
with pine bark and black plastic over the top and were planted through the
plastic you can see that they were potted plants had to cut a pretty big
hole to the plant through the plastic this is a nice certified organic
planting of rabbit eye blueberries with a weed mat on the surface this picture
was in 2011 some of you may remember John Vollmer the North Carolina agents
John Sun Russ now has the planting this was an interesting photograph
because the weed mat was added after the fact so you can see the cuts in the weed
mat where it was fitted around the blueberry bushes after they were in
place another rabbit I blue-gray planting in the North Carolina Piedmont
this amended site on black plastic there’s a pretty good slope here and you
notice there’s no concave areas in the field no dished out areas that would
trap water so a really good site preparation here and plastics holding up
quite well here we see another North Carolina Piedmont site this surface
mulches shredded wood mulch rather than then plastic or weed man but this was
also an amended site sod middle so this is a pick-your-own and the beds are are
quite a bit higher than the in the middle so the root system of these
blueberries is above grade this is a northern high Bush planting amended soil
the weed mat this photograph was taken in the Netherlands this fields in South
America and Chile it was amended and surface most with both with the aged
sawdust where soles are entirely unsuitable for blueberries it’s possible
to grow them in bark beds this was a interesting planting saw in 2009 in
South Georgia early ripening southern high Bush
growing in pine bark the EDS are just pine bark piled on top of the ground on
a rounded base and if you can keep the bark go wet they’ll grow in it and do
quite well common mistakes when establishing blueberries poor site prep
lack of raised beds lack of irrigation wrong blueberry species for your area
failure to prune when I see really commonly is its failure to adjust the pH
prior to planting it’s it’s tempting to get a soil test result back the pH is
not right but you’re ready to order plants but that’s really a mistake if
you go ahead and order the plants and plant them in a high pH site they will
really struggle and you’ll see a lot of intervenor chlorosis as you see in this
image that yeah following between the veins caused by
the high soil pH so it’s an iron deficiency but it’s pH rather than iron
so you really fix it by lowering pH rather than by applying iron so this
causes the the bushes to stop growing and with blueberries it’s really hard to
get them going again once you stunt them so really encourage you to get
everything right before you ever plant I might show a couple of images of
drainage problems in blueberry fields the image you see here is a field that
has a concave area in the center and it’s a fairly tight soil lots of clay so
the root systems are restricted when this soil is saturated the root
penetration just does not occur so you get these sort of flat pancake root
systems that just can’t support the bush so in the center of the image you see
the bushes that are yellowed and stunted and as you look around the edge of the
image where the slope is is improved you actually see the bush is doing much
better around the edges and even the two bushes in the foreground at the ends of
the rows where we’re drainage is better because it’s next to a ditch you see the
bushes doing much better I just have a more established root system so I really
want to avoid this type situation either by betting higher or by not planting in
these concave areas in fully drained soils just another example here of a
drainage issue the bushes in the foreground have a lot of new shoots
appearing those in the Far background as well but in between in the top center of
this image you see a lot of bushes that are stunted and again this is a this is
a drainage issue bushes planted fairly flat a fairly fairly tight sole that
does not stay well aerated and so the drainage issues over time become
apparent as the bushes grow and they the root systems get as big as they can be
and then they start going backwards so you could
dress this with soil amendments prior to planting and also with bedding and also
with the row orientation most large commercial fields in the southeast use
overhead irrigation it can be used not only for drought relief but also for
freeze protection in the spring these are fairly high volume systems small
operations often have drip irrigation that operates from wells uses a lot less
water and also avoid so wetting the bush overhead drip irrigation systems usually
consist of one or two drip lines down the road that either have punch in the
emitters that you add yourself at each bush or pre placed emitters that are
built into the irrigation line at regular intervals I often see 18 inches
as a pretty standard spacing for the pressure compensated drip lines and with
that sort of spacing you’re wetting the entire row rather than just at the bush
this is a drip system on a volcanic soil in South America just like this picture
because you can see the wetted zone around each bush this particular soil
seems to wet really well from a single emitter at the bush if you’ve got a
really sandy soil the water goes so straight down you don’t get the spread
that you need from the drip system so at that point you may need more than one
emitter or you may need a irrigation drip line that wets the entire row at
regular intervals I mentioned pruning earlier as an integral part of
establishment this is a picture of a new field pruned the six months earlier at
the time of planting in February to reduce the height we left a few bushes
unpruned and they really stand out by mid-summer the Bush that was not pruned
at planting is really long and spindly and sort of top-heavy the new growth is
all all upon the top of a really long will you compare that to the bush that
was pruned at the time of planting that Bush is much shorter sturdier it’s
already producing a multi trunk plant so blueberries are
i grafted they’re growing on their own roots so if you cut them back really
hard they’ll they’ll still come back true to type and and you’ll start
forming that multi-trunk plant when setting out a blueberry bush I always
prune off or rub off all the flower buds so that it doesn’t produce any fruit you
also would like to spread out the roots so that the root mass is no longer in
the shape of a pot in the first year your goal should be to avoid fruit
production entirely and just grow the plant vegetatively so once you remove
those flower buds the plant will not form any more flower buds until the next
year so it will put all its energy into vegetative growth so you you really need
to grow a bush before you can produce a crop blueberries are pruned every year
for the life of the plan so in year two you’d like to remove the low-lying or
weak shoots and crossovers and prune the bush to an upright habit if it’s run
really well you can allow to produce a little fruit in year two so in this
image we’ve allowed the bush to produce some fruit so we’re looking at it in
February of year two versus February of year three so picked a few berries but
didn’t leave enough fruit on there to impede vegetative growth so twelve
months later we’ve got quite a quite a good amount of growth and starting to
see all different ages of canes as the bush gets over coming out of the ground
so looking at the bush in year three at the time to prune February of year three
again shaping the bush producing an upright habit take out the low angle
branches and open the center but we’re starting to see all different ages of
canes now and over time you’d like to keep the bush as a multi trunk plant and
have all different ages one two three four year old canes emerging from the
ground they’re constantly replacing the oldest ones with with newer ones so here
we see two blueberry bushes one pruned one not pruned just a visual example of
the diagram we looked at in the previous slide so the bush on the right is pruned
and you can look at the bush on the left and
tell what you would have to cut to to make it look like the one on the right
so so really some some large cuts to remove those low angle branches and
crowding in the center mostly basal cuts to shape the plane
some of the phone calls you’ll get as a county agent will involve acres of
blueberries and some will involve one blueberry bush but the the principles
remain the same this is a ornamental planting in the landscape at the
Sandhills Research Station in North Carolina they’ve got a raised bed they
amended it they’ve got a bark mulch on the surface and you can see the
blueberries doing quite well even just a few plants in the landscape so the
principles that apply to to field scale production also apply to the homeowner
in the backyard gardener I hope this information is useful to you and hope we
can answer any questions you may have and thank you for your king

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