Blueberry Pruning

[Music] hello everyone this is Bill Klein with North Carolina State University in this session we will be discussing blueberry pruning pruning is essential for blueberries for lots of good reasons you want to manage the bush height keep it productive the very size increases when you prune you can remove diseased and ded canes you can keep the Bush from over cropping and producing small berries you replace over canes over time you maintain the shape and the flexibility of the bush you can even use pruning to alter the ripening period and in general pruning extends the life of the bush just a few basics about blueberries they are a multi trunk bush a long-lived deciduous woody perennial they form flower buds on late summer growth in early fall and then those buds bloom the following spring and fruit is produced in spring and summer they are not grafted so if you prune the blueberry bush down to the ground it will come back true to type here we see a lateral twig with large or healthy flower buds on the terminal end so in the winter time you can look at a blueberry bush and see these flower buds and estimate the crop potential for the coming year also when you prune you have to be careful to keep these flower buds if you prune too hard prune too many of them off you you severely reduce the crop the goal is to keep the healthiest fruiting wood so that you have larger berries so for bigger berries you remove the thin Twiggy matchstick wood and you try to keep thicker healthier fruit bearing chutes and what we're going to do in this presentation is discuss a stepwise method for pruning techniques that will do this quickly and economically without having to spend a lot of time removing individual twigs the way we will do this is by targeting canes that have lots of young productive wood and by removing the entire canes that have aged out and become less productive so in this image we see one in two year-old canes that are desirable that you would like to keep in canes that are older in the upper part of the bush that are three years old or older and you can remove entire canes and very quickly take out the unproductive wood and a blueberry bush the tools are used to prune blueberries are mostly hand tools or loppers and small hand pruners generally most of the cuts are made with the large long handle loppers refers you'd like to make big cuts and move quickly rather than making a lot of small cuts and spending a long time on each bush larger scale operators may use pneumatic or air power tool offers you'll see these in the fields sometimes with four drop hoses so you can prune both sides of two rows at a time with a four-man crew as the technology has become less expensive and more available we've started using more electric pruning shears or loppers and these are quite handy there they're quiet you wear the battery pack on a harness and you can move freely around the field pruning instead of being tethered to a power source as with other automated printing equipment I'd like to start the printing discussion with young bushes blueberries are pruned from the very first year and you'd like to remove the flower buds on a young Bush to prevent any very production at all in the first year or two it's also important with young bushes to shape them in the winter time you'd also like to remove succulent fall damaged shoots to avoid stem blight infection in the following year this image shows a close-up of damaged shoots on a young Bush at the base of the bush this is a really common problem on vigorous young plants because they don't stop growing soon enough in the fall of the year and don't harden off normally so you have a lot of this cold damaged wood that really needs to be removed in the winter time so it doesn't provide an infection court for disease the following season when setting out new plants you'd always like to prune off or rub off all the flower buds and cut the bush back half to two-thirds of the height and do this at the time of planting for potted plants so you want to separate and spread out the roots so that the root mass is no longer in the shape of a pot with the flower buds removed we look here at the 12 months of growth in the first year the bush grows vegetatively and doesn't produce any fruit so by February of year two bushes have increased in size and again produced flower buds so what do we do with that young bush in February of year two I you still need to prune every year so we would remove the low-lying and weep shoots cross over shoots and keep their healthiest largest upright canes you might leave a few flower buds at this pruning and allow it to produce a little fruit if the bush grew vigorously in the first year so here we see that same Bush February of year two just after we pruned it we're going to let it grow for twelve months we left a few flower buds so it will produce a few berries but the goal is still to produce vegetative growth and to grow the size of that Bush so by February of the year 3 as you see on the right the bush has grown quite a bit you see all different ages of canes starting to develop and be retained in the structure of that Bush here we see the bush in February of year 3 the bush is well established it's capable of producing a crop however we're still going to remove 40 to 50 percent of the flower buds and another important step here is to begin selecting new basil shoots that will replace the older cane so if you look at the bush on the right after pruning the notice there's all different ages of canes coming out of the ground so as the older canes age out we'll have younger canes already in place to replace them and here we see some actual bushes in the field the one on center right has been pruned the bush in center-left has not been pruned so if you look at the bush on the left you can see which canes have to be removed to make it look like the one on the right these are large cuts basal cuts down near the ground we will follow some of the same principles for rejuvenating the bush even when we get to mature bushes you'd like to continually be phasing out older canes in favour of younger would the young productive fruit-bearing wood is red in color in the winter time the older canes are a gray color so in this image we see a mature blueberry field that's been quite well pruned and you see lots of young red productive wood in the field blueberry printing is much faster and easier if you use a process of elimination by starting at the bottom of the bush and working your way up so the first step is to narrow the base of the bush remove any outline canes you remove crossovers and low-angle canes so anything that's going horizonte through the bush comes out I also like to remove one two three of the oldest canes or even more depending on the cultivar and the final step is to head back and then to selectively remove there's old brushy canes that we saw earlier in the upper part of the bush and also you may need to reduce the crop load on individual canes so after printing you should have canes of varying ages emerging from the ground but if you look at the before and after images here we've narrowed the base of the plant we've removed some canes to open up the center of the bush and to adjust the crop load we've looked at this schematically with drawings but what we'll do now is take an actual bush and reshape this older Bush with just a few large basil cuts what we're looking for here are older grayer canes that are more horizontal and that have passed their productive life so they have a lot of brushy Twiggy wood in the top of the cane here's our second cut a low horizontal branch and a third cut again taking out low angle branches that are crossing over so here we see all three of the first three cuts we're making cuts low down in the bush to shape the bush to a more upright growing habit the fourth cut here you can't really see the top of this cane but it's older grayer Twiggy wood so we'll cut it off mid height of the bush and take it back to a lateral so if you don't leave us stub when you make a cut the old canes are easy to spot easy to select and remove because they're more horizontal they've been weighted down in previous years by the weight of the fruit and they don't quite spring all the way back up so those crossovers that we're removing are going to be older wood and so if you start at the base of the bush and remove the crossovers you're automatically selecting for younger wood and for a more upright growth habit so that's what we've done here you see before and after the same bush with four pruning cuts here we see a different Bush but the same concept you're going to take out the crossover branches and stimulate new upright shoots from the ground if you look at the base of this bush you can see there are lots of different ages of canes coming out of the ground with the youngest ones still having red bark okay so we've shaped the bush we've made most of our pruning cuts by making these large basal cuts so what comes next a couple of things you need to look for higher up in the bush one is the possibility that there are branches that are overloaded that have too many flower buds and the other thing to look for hiring the bush is older canes that have aged out of their highly branched and have really small thin twigs so what we're seeing in this image on the right is an over cropped cane now in the winter time it had too many flower buds they were not and so now we see a branch with the sky behind it and unused all you see is green berries there's no leaves so that tells you that that branch has more berries than it can bear and so it's not able to produce any leaves so what you'd like to do is avoid this by pruning in the wintertime to reduce the number of flower buds before you get to this stage the way you make that flower bud reduction in the winter is by heading back so here we see two images of the same branch before and after it's prune just a simple printing cut at that central stem removes about half of the twigs then are covered with flower buds so you reduce the crop load just with with one cut on that cane pretty quickly the final step in hand pruning is to remove stems that have aged out and we're going to spend a little time talking about this because this is an important concept the image you see here are two stems from the same Bush on the same day one stem is a year older than the other so as blueberry stems age the very size really declines and you'd like to prune that wood out before it gets to this point of tiny berries the way I'd like to explain this is to take a single blueberry stem and follow it for about three years so we're not talking about the whole bush we're just going to look at one chute so in this image on the left you see July and August the flower buds are forming in the leaf axils so the leaves are still on the bush which are already starting to form flower buds the stem in the center is in the wintertime in January and the flower buds have formed out on the tips of this stem but further down the stem are vegetative buds or leaf buds so you take that same stem and you look at it on the far right here in May and June you see berries out on the ends of the stem where thee flower buds have bloomed and gun pollinated and formed fruit but if you look below the fruit you see leafy laterals that's where those vegetative buds broke dormancy and produced lateral shoots so if we follow that same stem into the second year the tip of the stem dyes those lateral shoots that formed below the fruit go dormant and they form flower buds so if that is left unpruned what you will see at the end of the second year is the stem on the right where you have laterals that have fruited the very size is smaller but there's more berries than they were in the first year they're just not as big but look at what's happening behind the fruit you also have these small vegetative shoots that are developing subtending the fruit and so we'll take this stem and we'll carry it into another year here in the third year the fruit becomes very small the stem has branched repeatedly the twigs have become really small flower buds or scarce and the berries that they produce are really tiny so before you get to this stage you would like to have prune to that branch out before production has dropped off so just to review those previous slides year 1 year 2 year 3 looking at an individual stem over time berry size decreases as the chute branches repeatedly so if we look at this on dormant stems in the winter time the image you see here is a rabbit eye blueberry year 1 year 2 and year 3 of stem growth and in the first year you'll have berries on the tip of that long whip second year laterals and more fruits but by the third year and beyond the branch becomes really Twiggy and unproductive and the berries are quite small at that point what you'd like to do is remove the entire cane selectively what you may see is a large cane in a blueberry bush that has all three of these stages growing on one major stem so at that point it's it's important to be selective in how you prune not cut the whole cane out keep the one in two year old productive wood but remove the wood that's gotten too old and lost its product to summarize winter pruning you're going to start at the ground and narrow the base of the bush you remove crossovers and low-angle canes remove one two three of the oldest canes or even more depending on how vigorous the bushes and what cultivar you're printing you'll also finally head back and then selectively to adjust crop load and remove those old brushy canes in the upper part of the bridge some are hedging or hedging at any time of year is something that comes up frequently it seems like a quick and easy way to prune blueberries without having to spend a lot of time doing selective hand printing and I'd like to cover this issue now because it is a technique that is sometimes used by commercial growers to reduce their printing costs but it can also be a really bad thing to do if you do it the wrong time of year you can prune off way too many flower buds and so you have to be careful in user using summer hedging as or hedging at any family year as a as a printing technique it's typically done in June in July immediately after harvest just as quickly as it can be done it only really works for early ripening cultivars and in sites where the bush has time to regrow in the same season so this mostly limits summer hedging to USDA hardiness zone 8 or higher so we're talking about coastal North Carolina most of South Carolina's most of Georgia this is a technique that can be used on early ripening cultivars the idea was some are hedging is to remove a lot of the fruit bearing wood that was just harvested and also a lot of the new leafy growth immediately after harvest and it's mostly done on southern pie Bush cultivars that ripen really early in May in June typically it's 36 inches to 48 inches high and a house top cut an angled cut so this this angled summer cut takes off a lot of the Twiggy growth that you would otherwise have to remove by in so it's a great savings on pruning costs but again a very specialized technique it's important to remember that this technique only works when there's time to regrow the bush above the mow cut so most of the crop produce the following year is going to be on shoots that grow that same summer and produce flower buds before winter also need to remember that this will delay bloom and ripening the following year because these are later produced shoots so they'll bloom and ripen three to four days to as much as a week later the following year as compared to unmowed bushes so here we see a mode field right after harvest you can mow the bushes quite severely if it's early enough in the season this is probably her first or second week of June on early Southern High Bush in North Carolina so you've got the rest of the summer there June July August September for these bushes to sprout and regrow and form new flower buds for the next season pruning is an every year event when you skip years of pruning you have to do some pretty severe pruning and lose some crop in order to bring the bush back into production so the best way to maintain the good crop load and consistent very size is to prune every year keep in mind that pruning is a disease management tool anytime you see Deadwood or infected wood in the bush this is your opportunity to prune that out most diseases are overwintering on the bush itself so anytime you see that diseased wood here's your opportunity to remove it winter pruning is our primary pruning strategy so you like to use that to maintain a narrow base multiple canes of all varying ages and use that winter pruning to to adjust the crop load and maintain a good very sighs finally some are hedging is a really specialized technique we use it every year in coastal North Carolina in zone 8 you can use it to manage Bush height and to reduce pruning costs it's also going to delay balloon but again it's a very specialized technique that not everyone will need with him thank you for your attention I hope this information is useful and good luck running your blueberries [Music]

Channel: UAEX Fruit & Vegetable

Views: 194,629

Keywords: agriculture, Arkansas, extension

Id: E_fglEl9mVo

Length: 20min 24sec (1224 seconds)

Published: Tue Nov 26 2019