(relaxing music) - "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.

January and February can be some of the harshest months on the Oklahoma landscape.

Today on "The Best of Oklahoma Gardening", we take a look at the effects last year's wild weather had on our herbacious perennials, shrubs and trees.

(relaxing music) There's no mistaking that we had a winter this year in Oklahoma, in fact, it was one of historic proportions and unfortunately, when the snow finally melted, our landscape was looking a little browner than it was going into that snow storm.

Now we know here in Oklahoma, that we range in cold hardiness zones from 6a to 8a for our plants.

These are the zones we typically consider when we're buying plants and are trying to consider if it will survive our winters.

At the far Western edge of the panhandle, the hardiness zone is 6a, meaning the average annual extreme minimum temperature from 1976 through 2005 is -10 to -5 degrees Fahrenheit.

Meanwhile, down in the opposite corner of the state, in south Eastern Oklahoma, the cold hardiness zone is 8a, or 10 to 15 degrees Fahrenheit.

Now for most of Oklahoma, we're in zone 7a and 7b, meaning we want our perennial plants to be able to survive winter temperatures as low as zero to 10 degrees Fahrenheit.

If we look at the Oklahoma Maisonette site, we can look at the February summaries for any of the stations across our state.

If you look at Oklahoma City, you can see that the temperatures were as cold as -6 one night and -15 the next night.

This is well below what we typically expect our plants to survive.

Furthermore, we remained below freezing for about 10 days straight.

Kenton, Oklahoma, one of the coldest locations in the panhandle had a low of -22.

Again, far below the average -10 degrees that is expected for zone 6a.

Then going back to the other warmer corner, Idabel, Oklahoma dipped down to -5, about 15 to 20 degrees below their average cold temperatures.

To give you a bit more perspective, these are the average annual lows for hardiness zones, 5a and 5b, in places like Iowa and Nebraska, but with one other difference, those locations often have a snowfall to help insulate the ground and buffer it from temperature swings.

Five days prior to this epic freeze, we had a high of 65 and about five days after, we were back up to 73 degrees.

So going back to our question, what does this cold snap mean for our plants?

Well, let me ask you another question.

How many crepe myrtles do you see growing in Iowa and Nebraska?

Unfortunately, the answer is not many, but really the answer for our question here about our plant's health is we don't know just yet.

For many of our plants, we're gonna have to just wait and see.

Now, obviously this storm was very impactful and maybe detrimental to many of our plants, but it's just a matter of time to wait and see.

Obviously a lot of our evergreens are now looking brown and so we're gonna have to check and see if they'll push out new growth.

You can see on this particular Deodar that we still have some greenery, but we're gonna be watching some of those other buds to see if they push out new needles.

It's sort of like when we watch our deciduous shrubs to see if they're gonna push out new growth in spring, we'll also be watching some of our evergreens as well.

It really depends on the health of the plant and the maturity of plant as it went into this cold snap, the hardier that root system, the more it will have energy to push out new growth.

If it was already weak and potentially damaged going into this, then it might be a little bit more problematic.

Now I suspect on some of our Woody plants, such as crepe myrtles and the Adina's, that they may have died back to the ground.

This means that the upper vegetation above ground may have died, but the root system may still be viable and if it's healthy and strong enough, it's gonna push up new growth.

- And the reason why it didn't freeze is because, actually, the ground insulated it a little bit.

And if you look at our temperatures, while our ambient air temperature got well into the negatives, the soil temperature hovered around that freezing point.

So what are some practical tips for assessing whether your plants have survived this winter freeze?

Well, the first thing that I'm least concerned about are native plants.

While they might not be used to those cold temperatures here in Oklahoma, a lot of our native plants have a range that's wider and can handle much of that cold weather.

The plants I would be most concerned about are anything that is tender or newly planted going into this winter.

I know that I often try to press the boundaries on some of those plants in hopes that they will overwinter.

And a lot of times we get lucky and we may have been able to overwinter some of those tender plants for the last few years, but anything that was right there on the hardiness zone boundary probably has been taken out by this last freeze that we had, unfortunately.

The next thing I would look at is the location and where that plant was located.

For instance, in a raised bed.

Anything that's planted in a raised bed or a container is going to be more susceptible to that freezing temperature, especially something like this that's an elevated table and does not have that ground insulation at all.

In fact that ambient air can go all the way around this planting bed.

Now, something like this, this concrete container here that we've built, it at a least has that ground heat coming up and is not completely surrounded by ambient air.

Now, it is exposed on the wall.

So again, it is a little bit more at risk versus those plants that are actually planted in the ground.

Now, for some of our clumping plants that we tend to think of as being evergreens like this Nandina.

While you might look at and see that it looks dead from a distance, but if you actually dig down into the center of it you'll find that it overwintered just fine, that there's plenty of green still in there.

Now, this is probably gonna push out a lot of new growth this spring and so you'll have to manage this dead material on top just to keep it in a nice look, but it's gonna recover just fine.

Now, keep in mind this is the time of year we often go through and clean up our garden, but we still have the chance of having a freeze until April 15th.

Now, chances are we won't have anything like we experienced in February.

Now, for some of our woody shrubs you can do the scratch test.

Now, we've shown you this method before, but I'll go ahead and recap it.

Basically, what you're gonna do is actually scratch the bark down at the base of the plant.

And you just wanna scratch it ever so slightly, or kind of nick it.

You can do it with a knife or your pruners.

And what you'll do is you'll see actually some green cambium.

If you see green cambium, then that means that this plan is actually still alive or this branch is still alive and viable.

Now, some of these outer tips may actually be dead, but that's fine as long as we know that there is some live vegetation still above ground it will resprout from this.

If you don't see anything, if it's actually brown and not green, then that means that that branch is dead.

And you can check several of these branches on like your crape myrtles, and hollies, and things like that.

If all of them seem to be dead because you don't see any green cambium, then likely it has died back to the ground.

Now, that doesn't mean that your plants still won't recover.

It just means that it's gonna have to resprout from those roots.

So that means we're gonna have to give it some more time to really see when it resprouts and allow those soil temperatures to warm up.

So there's still some hope.

Now, hollies and crape myrtles, they regrow pretty quickly.

So depending on your time, and your patience, and also your budget, you might have to evaluate those factors as to whether you want to wait for it to regrow and gain that size back or you wanna go ahead and replant.

Now, in larger woody plants such as some of our live oaks and our deodars, it might be harder to do a scratch test at the base of that trunk just because of the hard bark that's there.

What you can do is you can sort of do some of the scratch test on some of the younger branches to see if they're still viable, or again, just give it some time and wait to see if it pushes out new leaves.

Finally, I know it's been a challenging year after a catastrophic early ice storm in October and now record-breaking freezes in February.

Unfortunately, there's not one answer to weathering all of these storms, but that's why diversity in the garden is important.

And if you do lose a plant, that just means there's opportunity to add something new.

(jaunty music) This past February we had a deep freeze.

And when that happened a lot of people were concerned about the effects that it would have on our landscape.

And I was concerned too, but really the only thing we could do was to wait and see.

- Well, we're a few months away from that February freeze and the temperatures have warmed up as well as the soil temperature.

So, we're startin' to see some life come back into our plants.

Now it might not be full on like we normally expect, and so that's what we're gonna do is evaluate some of those plants in our landscape to determine what we need to do.

In some cases we can cut them back and unfortunately, in some cases that means pullin' those plants out.

And in some cases it means that they actually came through just fine and regrew just as good as they always do.

Today we're looking at Aucuba here in front of me.

We've also got some Abelias, Nandinas, and Mahonia, and all of these really are gonna be treated in the same manner.

They typically are a evergreen plant and as you can see, a lotta that foliage did get burned back.

Now, in this particular one, this Aucuba, if we're looking at it you can see where there's definitely some dead tissue as it's all black.

You can also see where there's still green, viable tissue.

Unfortunately, on most of this the green stems, we're not really seeing any regrowth.

Where we're seeing the growth come back from is down at the base of this plant.

So, for this situation what we're gonna go ahead and do is take this plant all the way back, leaving this new growth to regenerate and fill in.

And that's what we're gonna do on a lot of our plants.

But first, we'll tackle this one here.

(upbeat music) Now that we've got our Aucubas cleaned up here, one thing you wanna be careful of is make sure you're not throwing away any of your plant labels.

So, if you have removed any of your branches and those are still attached, make sure you've got that written down, take a picture of it or something so that you remember what these plants are in your garden before those head to the compost pile.

So next here, we've got some Abelias.

Again, you can see that there's some regrowth coming up here on top.

It's very little amount of regrowth.

The majority of it is all dead tissue.

There's a lot more regrowth down at the base of the plant where it stayed warmer.

So, this plant, we're gonna take all of these back to the ground.

You can see there's about three large ones, and that's just gonna give it a more regenerative pruning as well, and also help maintain that size of that plant.

So, we've got a lot of the dead cleaned out of these shrubs here and we're gonna treat our Mahonias and our Kerria Japonica the same way.

You also might find that your Crapemyrtles have died back and if you're already starting to see regrowth coming up from the base, then it's time to go ahead and prune those all the way back to the ground, too, and allow that new growth to continue to rejuvenate the plant.

You might find that in some locations your Crapemyrtles are still regrowing from the top and which you don't necessarily have to prune them.

It depends on, again, the location around the state and also the micro climate.

I've seen on different sides of a building where some Crapemyrtles have died all the way back to the base and then on the other side of the building they're still regrowing from the top.

It just depends.

So now over here you can see we have an Indian Hawthorn and there's actually part of this plant that's still alive around the base that was naturally covered by the organic matter and the leaf litter that was there over the winter months.

But, for the bulk of it, you can see that it is kinda dead.

And because we are a at botanical garden and we obviously want to put our best foot forward and make it pleasant for everyone to enjoy aesthetically, And so, here we're sort of evaluating the plant and have determined that it's just best to go ahead and remove it because it is a slow grower.

So, We're gonna remove this one.

Now if this was in your back yard and you wanted to go ahead and wait and you didn't wanna purchase another plant and you wanna invest time rather than money, there's no reason you couldn't prune this back and try to wait for it to regrow.

It's just gonna take a little bit of time.

Now some of the other plants that we are seeing around the garden showing effects are Live Oaks and our Nellie R. Stevens.

We're excited to see they are regrowing and they're startin' to push out new leaves.

So, even though they were evergreen, they turned brown, we're seeing new growth come back out on those.

So, those we don't have to do anything to.

Now on herbaceous plants, our Cannas are actually coming back.

I know, especially in Northern Oklahoma, some people might have lost their Cannas.

Again, depending on how aggressive of a stand those Cannas were and also, how much debris was maybe covering and mulching those Cannas through that freeze.

Another plant that we're seeing that didn't do so well are our Azaleas.

Here in North Central Oklahoma they didn't seem to come out of it so well and we saw a lotta loss from them.

However, I know over in Tulsa, they had a beautiful spring display of Azalea.

So again, it depends on where you were in the state as to those freeze temperatures and how long exposure they might have had to those cold temperatures.

Another plant that we have struggled with seeing regrowth on are the Deodar Cedars, unfortunately.

They are still not looking good, so it looks like that they might need to be pulled as well.

But, just keep in mind that if you have plants kinda like our Indian Hawthorn that we're gonna go ahead and take out or our Deodar Cedars, that every time you have to pull a plant that's just an opportunity to plant something new.

- We're back here in our keyhole garden.

And it's been a few years since we've been in here and visited it with you guys.

So we wanted to kind of showcase it and tell you what's been going on.

A couple of years ago, we planted some perennials in here, including just a couple of Helen Von Stein lamb's ears, and you can see how they have taken off.

They really enjoyed the soil that they're growing in here.

And of course, we've still got some of the Mexican feather grass as well.

So at this point, we're kind of looking at this lamb's ear and we need to do something about it.

It's kind of taken over.

So I wanted to share with you what you might do if you have a situation where you've got some perennials and you're looking at cutting them back, getting them ready for the spring.

And what you're gonna do is just take a couple of hand pruners or whatever kind of pruners or scissors you might have for landscaping.

And we're gonna go in here and just start chopping some of this old growth back.

When you get in here, you can see how there are these older canes, and a lot of this is just old growth up here.

But if you go down into it where it's been warmer over the winter time, you can see there's new growth coming on.

So we're just gonna trim back to where that new growth is, and that'll allow fresh, new growth to come out this spring.

(gentle music) After you get a lot of the bigger stuff taken out, what you're gonna do is just rake out some of those leaves and clean it up a little bit more.

And you can see that the plant itself is not actually as big as what it first appeared.

So I think originally we planted about five lamb's ear, and you can see that this was one plant, but as it grows and the stems fall to the ground, they tend to root themselves.

In fact, you can see how there are roots on some of these.

And so, a lot of this is just babies off of this main plant.

Now we're gonna go ahead and leave this one, but I think this plan up here in the foreground, we're gonna go ahead and remove it.

So when we dig it up, there's a lot of plants that can be made from this.

And really, you're just gonna try to get into the outside of the plant.

Lamb's ear is a pretty tough perennial, so you don't have to be too cautious.

You're definitely going to be dividing some of this up.

Again, there, you could see the roots, how those have grown, and that's over the rocks there.

So we're just gonna go in here with our shovel and start digging.

All right, as you dig it up, you can see we've got a good clump here with a good amount of root system on it, but this is actually a really large plant.

And as I was digging, it actually divided itself.

You can see, here's another plant here.

And again, we're just gonna pull some of those roots, but even this can be divided further, and actually wants to.

You can do this with your hands.

A lot of times they'll just tease apart that way.

Or you can go in with your shovel on something larger like this, and actually use your shovel blade to cut it in half and divide those roots.

'Cause they can be quite coarse.

So out of that one plant, you can see that we were able to multiply it and get four new plants to add to our garden.

(upbeat music) It's been a year since last year's ice storm, and we wanted to talk with Mark Bays, our urban forester, a little bit about the recovery efforts that have been happening since last October.

So Mark.

- Yeah.

- It's been quite a year, right, for trees.

(laughing) - It's been crazy to think where we were just a year ago.

I mean, I was without electricity for 13 days in a row, and it's just amazing.

And as we look back to see how, not only the ice storm, but also the cold weather, that's the real pandemic, I think, that's been happening this year.

- Yeah, so to kind of recap.

So this time last year, year to the date almost, I mean, look at what the trees look like with all of these leaves on it and covered with ice.

- [Mark] Totally covered with ice.

- [Casey] So let's talk a little bit about the devastation that we saw right after that.

- Right, so this tree that we're standing right next to here, it's about an eight inch caliper tree, and we've been trying to figure out just how much we've lost as a result of the ice storm.

So when I talked with some of the cities that are in the central Oklahoma city area, based on the amount of tonnage of debris that was hauled away, we lost about 3 million of these trees that we're standing next to.

Now, if you think about that, I mean, that's not really the case.

That was just the debris that was taken away.

- [Casey] Right.

- But think about the other debris that we still have in our natural areas, in people's yards, that they haven't even dealt with yet.

So that could be as high as seven, even 10 million trees that we may have lost.

- [Casey] Now and that's just in the Oklahoma city area, based after the numbers that were reported.

- [Mark] That's only on the numbers that are reported.

So it's much higher than that.

- [Casey] And then again, that's also based off of just the limbs and stuff equivalent to.

- [Mark] Equivalent to that size of trees.

- [Casey] 3 million of these trees.

Wow, that's incredible.

- And if you think about the benefits that we lost from that, you think about the soil protection, you think about the air quality.

There's lots of human health benefits that we get from these trees.

If you're just interested to learn about more about how trees improve your everyday lives, you can go to this really wonderful website.

It's called healthytreeshealthylives.org.

- [Casey] Okay, so we definitely know trees are important and it wasn't just the ice storm that was so detrimental.

- Then we were followed up in February by this crazy deep freeze that we've never had here in Oklahoma before.

- Yeah, we lost so much of our thin bark trees during that time, and we're actually still seeing some of that damage.

We've seen a lot of oak trees throughout the summer months come out fully leafed and lose all their leaves.

We're seeing a lot of problems with different pine trees, because they came fully leafed out and the only common denominator is those that didn't get the ice damage.

They've got the freeze damage that we're just now beginning to see.

- Yeah, so obviously things are affected by their own sort of resistance, how mature they were, if they were already in decline going into all of this that sort of maybe took some of them out.

- Right.

- Last year when we talked, you said just kind of take care of any of the widow makers, the ones that were hanging.

- Yeah.

- Let's talk about what we need to be aware of with our trees right now.

If we still have trees, I think the leaves are kind of hiding some of that damage.

Right, am I correct on this?

- Oh yeah, that's what's gonna happen.

The leaves came out last spring, everybody went on their way.

They all got happy.

We forgot about how much damage is still up in the trees.

So that's the first thing is we still saw trees' branches die.

So anything that's dead, go ahead and remove that.

Remove those hangers.

Try and cut them back to the next union.

You've done a lot of shows on proper pruning and everything like that.

If it's too much for you, use a professional with that.

The other thing that you'll probably be seeing is, if you were fortunate to keep a lot of your trees there, is you'll begin to see those sprouts, water suckers, and those are those little branches that start shooting up in time.

And that tree, what it's trying to do is replace all the branches that were lost, so don't take all those off at one time.

There are a number of them that are growing straight up, and those straight up ones, they have a much stronger union to that branch, and so those are the ones that we're trying to protect and save.

Eventually they may need to be removed, but right now those are the ones that we're trying to save.

- And by slowly thinning off some of those water sprouts, you are gonna to encourage more of that energy into one or a couple to make those stronger.

Is that kind of the thought process?

- So why you're seeing so many of those sprouts coming out right now, is the tree has been damaged in other places, and so it realizes it wants to replace its food source, which comes through photosynthesis in the leaves, so that's why it's frantically replacing everything.

So if you remove all those water sprouts, you'll take away all that food production.

That's why it's important to be a slow process, 'cause you're trying to allow that tree to replace the food that was lost.

You just can't continually take all those suckers off, because you're continuing to take-- - [Casey] You're doing the same damage as the ice storm did.

- [Mark] There you go, uh huh, that's right.

- [Casey] Very good, okay.

- So if anybody needs to have any information at all on what they need to do to help their trees survive from this ice storm, they can always go to our website, forestry.ok.gov.

- [Casey] Excellent, thank you so much, Mark.

- [Mark] Thanks.

(upbeat music) - [Casey] There are a lot of great horticulture activities this time of year.

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

(upbeat music) Thinking about starting a garden this season?

Next week, we've got all the options for constructing a raised bed.

(upbeat music) (gentle music) 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.

And we always have great information, answers to questions, photos, and gardening discussion on your favorite social media as well.

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You can find this entire show and other recent shows, as well as individual segments on our Oklahoma Gardening YouTube channel.

Tune in to our OK Gardening Classics YouTube channel to watch segments from previous hosts.

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.

(gentle music) We would like to thank our generous underwriter, The Oklahoma Department of Agriculture, Food, and Forestry.

Additional support is also provided by Pond Pro Shops, Greenleaf Nursery, and the Garden Debut Plants, the Oklahoma Horticultural Society, and Tulsa Garden Club.

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