- [Narrator] Oklahoma Gardening is a production of the Oklahoma Cooperative Extension Service as part of the land grant mission of the Division of Agricultural Sciences and Natural Resources at Oklahoma State University, dedicated to improving the quality of life of the citizens of Oklahoma through research-based information.

Underwriting assistance for our program is provided by the Oklahoma Department of Agriculture, Food, and Forestry, helping to keep Oklahoma green and growing.

Today on Oklahoma gardening, we are talking about fruit trees.

Becky Carroll shares with us about frost pockets, chilling hours, and how to hill them in until planting.

Then we head over to Greenleaf Nursery to see all the work that goes into their container peach trees.

(bright acoustic music) - So often we think of the Oklahoma landscape as being flat, but actually there is some slight elevation that can play a critical role in your backyard fruit trees.

Today, joining us is Becky Carroll, the OSU extension specialist.

Becky, let's talk a little bit about these frost pockets that we can find in our landscape.

- Yeah, cold air is a lot like water.

It's gonna flow downhill and collect.

So these low spots, like right here...

This is gonna be maybe a couple of degrees colder than even up where we were starting.

And so, it really makes a big difference on the location that you plant your trees.

- So, why do you not want fruit trees in frost pockets?

Obviously, 'cause it can do some damage but let's talk about the mechanics of it a little bit.

- So, you know, most of our fruit trees are gonna be blooming early spring.

And with Oklahoma's weather, we never know when we're gonna get that last spring freeze.

And so, if we can keep those trees a little bit warmer, we'll have a better chance to have a fruit crop.

And so, even a degree or two can make the difference between having fruit and not.

And so, we saw it last year a lot of areas where those low spots, that late-April freeze that we had last year, those low spots had trees with no fruit in the bottom part even.

And so, it can make a difference just in that tree space.

So, maybe the top part of your tree has fruit and the bottom doesn't.

So, it can make a big difference in just little things.

- So, we're out here at the Cimarron Research Station and there is a bit of a...

It's flat but there's a bit of elevation from the north side all the way down to the south with pecans behind us.

Tell us a little bit about how y'all have laid out your planting to deal with that elevation.

- So, peaches are one of the earliest blooming, so they usually bloom the middle of March.

You can just about put your clock on March 15th through the 20th in this middle part of the state.

And so, they're blooming before pecans and apples and pears usually.

So we want them on the best location, the best site.

And here on the station that would be right up on top of this hill.

And so, it had the most elevation, really good soil so when we get cold air, it settles down that hill, flows all the way down to the bottom.

And last year, we had some of those trees in the very bottom part of...

The pecan trees had some freeze damage and the ones up a little bit higher didn't have any problems.

And so, it can be a big problem if you're in one of those low areas.

And it doesn't have to be a big slope like this; it can just be a little bit of a dip in the area can cause a big issue as well.

- All right, so talking about elevation, is there a particular side that we should be looking at too on the slope or... - You probably, if you have a choice, an eastern-facing slope is gonna be better than north or south just because it's gonna warm up a little bit slower and it's not gonna be as cold if it's on the northern slope.

The south facing slope's gonna get more sun, more warmth.

And so, those buds may push and come out a little bit quicker.

So, eastern slope a little bit better, but I would really look at elevation first.

- All right, Becky, thanks again for giving us a new perspective on how to look at our landscape.

(bright acoustic music) - Hi, I've been getting a few calls already about bloom this year on fruit trees and on some of our small fruit plants.

We've got really erratic bloom.

We've got some blooms that are past, even at shuck split, and then some that are just now blooming and some that are still thinking about pushing out into a bloom.

And this may have to do with the amount of chilling hours that we received this past winter.

And Casey and I talked a little bit about this in a February segment, but just a recap: A chilling hour is the hours that we have - Between 34 and 45 degrees, after the trees become dormant in the fall.

And so we count up the number of hours that are in between those critical temperatures, 34 to 45 degrees.

And so normally if we look at the average chilling hours for Oklahoma from down in the southeast part of the state, we may have 800 hours, maybe up to 1,000.

And as you go further north, then we have, we go maybe up to 12 or 1,400 hours on average.

And so most of the trees that we're going to recommend that you grow are within that chilling hour range.

So for a lot of our peaches, they may range anywhere from maybe 700 to 950 or even over 1,000 hours of chilling that is needed.

But why do we need chilling hours?

That's probably a good question to answer.

Chilling is important for, if you think about these fruit buds, they started being initiated back in the fall, but they have to have enough chilling hours before they are differentiated or developed into a fruit bud in the spring.

And we need a certain number of chilling to accomplish that.

So if we have a lot of chilling, we'll have a lot of fruit buds and this is also for pecans as well.

And so sometimes our lateral shoots need more chilling hours and so on a high chill year, we may have more laterals push because they've had extra chilling.

The terminal buds, normally if we have flowers on the end, those will need less chilling and they will push sooner.

So we'll have flowering usually at the end before we'll have the lateral buds push.

Now if we don't have enough chilling hours, in many states like Southern Texas, down in Florida, along the coastline, they don't get enough chilling hours to satisfy the needs of things like apples and pears and cherries that need 1,000 or more hours of chilling normally.

So they have to look at trees that will bloom and start the growth properly in the spring using less chilling hours.

So we have some peaches, if they have like Texas Star or Florida or Gulf in the name of that tree, it's probably considered a low chill variety.

So they are gonna be best suited for those areas with low chilling.

But things that we recommend are gonna have those higher chilling requirements like 800 to 1,000 hours for Oklahoma.

Now if, like this season, there are some areas in the southern part of the state that have had less than 300 hours of chilling and the thing about chilling hours is if we get above 60 degrees, we start losing those accumulated hours, so we can end up with zero hours if we get too warm in the wintertime and so this is probably the least amount of chilling hours that I have seen in any season that I've been working with fruit trees.

Less than 300 is very, very low and so on peaches and other stone fruits, they are self pollinated.

So if you end up with blossoms, you may still have fruit.

But if we're looking at things like apples and pears, we may miss our pollination window if we don't have enough chilling hours for some of the trees.

We've got this apple that is starting to bloom.

You've got some flowers right here and then this one on this side is supposed to be the pollinator and it's just now starting to push out a few buds right now, so it's behind quite a bit.

So if we need pollen from this tree for the bees to move to this tree, we're gonna miss that window of opportunity to provide the pollen source for this tree.

And likewise, when this tree starts to bloom, this tree will probably be finished and we won't have a pollen source for this tree.

So we may end up with lots of pretty flowers, but no fruit just due to the window of opportunity of that pollination not happening because our flowering is off this year due to the low chilling hours.

Now in Stillwater, we've got about the first part of March when we think of our chilling hours for like apricots and those early blooming trees like apricots and plums and almonds, maybe peaches.

We were about 500 chilling hours for the central part of the state and since then we've accumulated a little more.

But a lot of my early blooming trees like apricots and almonds, they're just now blooming, which is very, very late and so they require less chilling most of the time but they just haven't bloomed like they normally would.

And most of the time, our peach trees, they're gonna be blooming in the central part of the state about March, 15th to the 20th and so this year it's been very late.

So we'll see how it goes.

But for right now, that may be one reason that we have less fruit production this season.

(relaxing music) - Today we are here at the Cimarron Valley Research Station in their fruit orchard, and we are joined by Becky Carroll who is our fruit tree extension specialist.

Becky, I know a lot of times this time of year people are looking to add fruit trees into their backyard.

Tell us a little bit about some advice you might give that first-time grower.

- Well, the most important thing is make sure that you're buying something that is adapted for your area.

So, Oklahoma is not California or Washington, so we have very fluctuating temperatures.

And so, we want something that's gonna be adapted to our climate and the amount of disease pressure that we might have.

So that's really important things to consider when you're looking for a fruit tree.

- [Interviewer] Now, I know a lot of times that's the big thing is when is the last frost gonna happen?

And that can be detrimental to those fruit being set.

- Right, we wanna make sure that the trees that we're ordering are gonna be adapted to our climate.

And one way we can kind of look at that is the number of chill hours that are required for that tree to start to grow in the spring and produce fruit.

And so a chill... - Talking about the winter hours, right?

- Yeah, the cold temperatures.

And it has to be between 32 degrees and 45 to 50.

There's a couple of different models.

But the number of hours after they go dormant kind of we accumulate those hours when they're between that 32 and 45 and those numbers we accumulate to see how many chill hours these trees might need.

And in Oklahoma, we range from about 800 chill hours that we normally get in the southern part to maybe a thousand or 1200 hours in the northern part of the state.

And then some of these trees are going to be low-chill varieties or higher-chill varieties.

And you think of things like apples and pears and cherries that are grown in the northern states that do really well up north.

They usually have a higher chill hour requirement.

- [Interviewer] So they need more cold temperature in order to set that fruit.

- [Becky] Right, and it can't be too cold because that doesn't count.

It has to be above 32.

Now, if we get above 60, it starts to take away some of those hours.

- [Interviewer] It actually subtracts.

- Yes, it will take away our chilling.

So if we ended up with a really warm February, we might lose some of that accumulation that we had gotten earlier.

- Okay, so it kind of can get complicated if you're trying to buy fruit trees, but I know some companies make it a little bit more simple by just entering your zip code and we'll recommend certain varieties for you.

- And it's also by zone.

And so, most of Oklahoma's gonna be in zone six and seven.

And so, just know where you are in the state and then find those trees that are gonna fit.

But like you said, some you just put your zip code in and they say, "These are the trees that are gonna work for you."

- And are there any that you probably should avoid?

Like if it says Texas or Florida?

Should we avoid some of those southern states?

- Those have been bred to do well in those areas without a lot of chilling.

And so, if you see something that says Texas star or gulf something or Florida sweet, those are probably gonna be low-chill varieties.

When we plant those here in Perkins, in the central part of the state, they may meet meet all their chilling requirements before February.

Get a couple of nice warm days and they start to bloom or even leaf out.

And so... - Which means if we have another freeze that comes through, you've lost your crop.

- Right, and sometimes you can even have tree damage because if they're actively growing, you can have wood damage to those trees as well.

So it's best to stay away from those - And that that's applicable to all of, most of your fruit trees?

- Most fruit trees are gonna have a different amount of chilling needed.

So, things like figs and pomegranates, they just need to lose their leaves and they're ready to start growing again.

And so, that's why a lot of the time, our figs die back to the ground every year because they don't actually ever stop growing.

They just start accumulating those hours and start...

When we get warm, they start growing again.

And so, if they're actively growing and we get temperatures that are below about 17, they're gonna die back to the ground.

- So, what about that backyard gardener who might live in an urban space that, you know, is very limited on space available for a fruit tree?

- Well, they might consider something... Well, they need to be careful because if they're planting things like pears or apples, some cherries and plums even, they may need two trees for cross-pollination.

Now, it just doesn't mean you can plant two golden delicious and have pollination.

You have to have two complementary varieties that flower at the same time.

And so, most of the time the catalogs give you a good idea of what is going to pollinate each other.

So, they give you some help there.

So, if you have limited space, you might consider growing something that's a columnar type of apple as short spur growth instead of long shoots.

And so, it stays more upright and not... it doesn't spread out very much.

Or you might look at a dwarf apple tree.

These are some of our dwarf types.

We have some semi dwarf.

But you can keep them at a size that's manageable with your pruning.

And so, it is important to make sure that you know the pollination requirements, especially for those pears, apples, cherries, plums, most of our peaches.

- [Caretaker] Nectarines and things are gonna be self pollinating.

Peaches and nectarines are gonna be more difficult to manage the insect and diseases.

They have a lot of issues, and have to be sprayed, pretty much, from bloom time until harvest.

- [Documenter] And that can be organic spray, too.

- It can be organic spray, but it has to have some type of insect and disease control.

We start disease control on peaches at bloom time, and then introduce our insecticides at petal fall.

So we're avoiding spraying those pollinators.

But it has to be continued every 10 to 14 days until harvest.

So it's a big investment of time.

- Yeah, okay.

Well, what about sourcing these trees?

What size should we be looking for?

Because I know they vary from anywhere from a whip that you get in a box, or a little sack, to something that's already over our heads, and in a container.

- Well, I like to invest in those smaller trees, if possible.

And I like to order my fruit trees from a nursery that specializes in fruit tree production.

They're gonna have the best quality, they're gonna have the best varieties, and know what they're selling you.

So they can provide you some assistance, and what's gonna work best, as well.

But if you buy a large peach tree, and I've seen some that may be 10 feet tall, and you bring it home to plant in your yard, I'm gonna recommend that you cut it off at knee-high.

And so, it may be a $100 worth of tree, but you're gonna cut it back to knee-high.

So that's very difficult for you as the homeowner, to do that pruning, but if you don't get the structure set, especially for peaches, and a lot of those prunus types, you're never gonna have enough sunlight, or airflow, through those trees to help with the disease problems.

- And not only are you losing a lot of your investment that you just paid for, but also, it's usually a larger diameter that you're cutting, versus some of those smaller whips.

- Yeah, if I can, I will order about a 24 inch whip tree, plant that, especially for peaches, and it will catch a larger tree in year three when it starts producing.

So they have better adaptability, better transplanting, and it's just gonna be easier on your pocketbook, and your heart, (caretaker and documenter laughing) when you have to do that pruning to it, as well.

- Well, I know this is kind of the time that people are starting to order, so what do you do once we get those in?

- I like to have my trees delivered about the time that I'm ready to plant.

And I like to plant about mid-February to early March.

And so, I got in a box of trees just the other day, and I'm not really ready to plant just yet.

Now, if you get 'em in early, and you're ready to plant, go ahead.

But if you're not ready to plant, I'm gonna show you a way to kind of tide them over until you're ready to get them in the ground.

- [Documenter] All right, let's go take a look.

- Okay.

So I've got the order box that I received last week.

And so, whenever you get them in before you're ready, you wanna make sure you open 'em up, make sure there's enough moisture in there, because if they're too dry, you're gonna have trouble with their survival.

And so make sure they're moist.

A lot of them will come in with peat moss, or newspaper shavings, or something.

And so, I'll leave all of that on right now, because we're gonna heal them in, H-E-E-L, heel in.

- [Documenter] We're not planting.

- Not planting.

We're just gonna store them until we're ready to plant.

And so what we've done, and this had plastic, so we removed that, but if it's got other material, the newspaper mulch, just leave that on there.

It'll be fine.

Now this is just protecting the roots from freezing or drying out.

And so, we're gonna lay them in this little ditch that we've already prepared.

So, it's kind of a flat surface, and then it levels out, and we're gonna protect the roots the most.

So, we'll use this mulch pile that we've got here with some soil in it.

- [Documenter] And just cover 'em up.

- [Caretaker] Just cover the roots well, and then make sure that it is wet.

Right now we're kind of in a drought, so we wanna make sure that we keep this moist while we're keeping them heeled in.

- [Documenter] And if the trees actually came in a little bit dry, would you wanna soak those before?

- [Caretaker] Yeah, yeah, I think so.

Soak them for a few hours before they are placed in the hole here.

And that goes for before you plant, as well.

You would wanna make sure that they have a lot of moisture.

- And how far up do you go?

Just where they come.

- Well, you can cover the rest of it with mulch if you'd like, but the most important thing is just make sure that it's tight with no air pockets in here, so it protects those roots.

I mean, it looks pretty rough.

- (laughing) I know, you're just stepping on it.

- (laughing) But it's really not gonna hurt them.

And the more soil mulch that we're covering them with, the more protection it's gonna provide.

Now, we really want these to stay dormant until we plant them, and so that's another reason we could cover them completely over.

- Okay.

So basically, we're just laying them down.

They're not gonna start rooting in here or anything like that.

- Now, if you leave them, they will, (caretaker and documenter laugh) but we want to just keep them here until we're ready to plant, which is gonna be in just a couple of weeks.

- Okay.

So it just buys us a little time until we have that perfect spot figured out.

- Yep.

- All right.

Well, thank you, Becky, for this little introduction into backyard fruit trees, and I know there's a lot more to be known about this.

- So, we will catch up with you again later.

- All right, thank you.

(acoustic music) - Today we are just outside of Fort Gibson at Greenleaf's Hidden Lake Nursery and joining me today is Mark Andrews.

Mark, a lot of people are eating those delicious peaches this time of year, but you're working on the future crop of peaches, right?

- Right, so these crops that we're working on are for next year and future years beyond that.

- Okay, so we've got tiny little peach trees growing here but these aren't what's gonna be the finished product, right?

- No, this is just... these are young peach seedlings that are here in the field and what we're gonna do is use these to bud the improved varieties that everybody's looking for at the grocery store.

So, if they're looking for a Hail Haven peach or a Red Haven peach, whatever variety it is, that's what we bud onto these so that we know we've got a good consistent crop and that it's true to the name of the peach.

So, what we do is we collect wood from known trees.

So, we go to orchards where we already know what the tree is and we collect wood from that particular variety.

And then what we do is we take small little buds and we go ahead and graft those onto these seedlings.

And then after the bud goes ahead and heals onto that tree and everything, then we break the seedling tree off and put all the energy into that bud and start a whole new tree that is true to the name of the variety.

With peaches, they're fairly rapidly growing plants.

So what we'll be doing is we'll be grafting them right now at this time of year in, you know, early summer and in about four to five weeks is when we'll come back and we'll start bending these tops of these trees over because by then they'll be healed onto there and we wanna start pushing the growth into that bud and start the new tree.

- [Interviewer] Why do you bend them over instead of just cutting the tops off?

- It seems to work better to bend it over.

There's still a little bit of energy that comes from the leaves and everything like that to feed the plant and everything, but by breaking it over, you're disrupting the growing tissue, the xylum that transmits the nutrients and water.

So we're stopping that from going up into the rest of it; it's all going to the bud.

But there's still enough leaves to kind of support the plant and keep it going.

- [Interviewer] Okay.

All right so, you've got next year's crop growing over next to us also.

So, those are the ones that have that scionwood already growing out, right?

So, are those ready to sell yet, or where are we at in the stage?

- [Mark] Those trees... For the way that Green Leaf Nursery operates is those trees will be dug this winter and then we will put them into containers and grow them for one more growing season, and then we will sell them to the end consumers.

- [Interviewer] All right, so we've got... - So we're still two years away even with what we've got here.

- And these are a year old, right?

You grew these as seedlings.

- These seedlings are a year old, yes.

- So, you've got what now?

Four years invested in that peach tree before it gets to the nurse nursery really?

- Yes.

- So that's what we can soon see at next year's nurseries.

- Correct.

That's right.

- Thank you, Mark, so much for sharing this with us.

- You're welcome.

(bright acoustic music) - [Narrator] There are a lot of great horticulture activities this time of year.

Be sure and consider some of these events in the weeks ahead.

Join us next week on Oklahoma Gardening as we walk through all the home lawn concerns.

- It's winter in the garden and today I wanted to talk to you about something that you might... (acoustic music) - [Narrator] To find out more information about show topics as well as recipes, videos, articles, fact sheets, and other resources including a directory of local extension offices, be sure to visit our website at oklahomagardening.okstate.edu.

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Oklahoma Gardening is produced by the Oklahoma Cooperative Extension Service as part of the Division of Agricultural Sciences and Natural Resources at Oklahoma State University.

The Botanic Garden at OSU is home to our studio gardens and we encourage you to come visit this beautiful Stillwater gem.

We would like to thank our generous underwriter, the Oklahoma Department of Agriculture, Food, and Forestry.

Additional support is also provided by Pond Pro Shop, Greenleaf Nursery, and the Garden Debut Plants, the Tulsa Garden Center at Woodward Park, the Oklahoma Horticultural Society, Smart Pot, and the Tulsa Garden Club.