Hi there, I'm Katie Wagner from Utah State University Extension in Salt Lake county.
Let's go take a look at your garden.
Hey, we're here at a busy urban area here in Salt Lake County and I wanted to show
this great example of sun scald injury or "southwest injury" in trees.
You can see this damaged portion here all the way down to the dead tissue underneath
facing the southwest exposure.
And what happens with this injury is that during the wintertime when the sun is
shining and there may be snow on the ground and so there's white light
reflecting onto the trunk of the tree, this area heats up, and when it heats up
the cells become activated. They're thinking "it's springtime, it's time to
grow." and then at nighttime when the weather cools back down and the
temperatures go to freezing, those cells are killed.
Overtime this injury can cause sever cracking and damage of the tree, and we
can see that all the way from the bottom of the tree all the way up into the canopy
this severe cracking. This will eventually kill this tree so this something that we
definitely want to try and prevent against in our landscape trees.
This young Mountain Ash is especially susceptible to sun scald or southwest
injury. It is a young tree, most young trees and shrubs have a very thin bark,
and this thin bark is more prone to cracking than an older, more mature tree
that has a thicker, more developed bark. So it's very important that we protect
this tree from sun scald injury and the way that we're going to do this today is
by wrapping with a white tree wrap. You do want to use a white material. White
reflects the sun away from the trunk of the tree, and what that does is that keeps
the trunk physically cooler. So you remember before if the sun were to hit
this tree trunk and it were to heat up the cells just within the bark and activate
those cells, that those cells at that point in time would be prone to being
killed when the temperatures drop back down to freezing, and that's when we see
our cracking. So we want to make sure that we protect this tree by wrapping this tree
and what I'm going to do is I'm going to start at this base here.
Tie my wrap down.
By the way this wrap can be purchased at most home and garden stores.
And now I just want to do a pattern like this, especially making sure that the
south west facing exposure is protected.
I can overlap, that's fine.
This wrap goes on towards late fall, early winter when the threat of freezing
temperatures is present, and it needs to come off early spring time after the
threat of freezing temperatures is passed. Don't want to leave this wrap on all year.
If you do that, you present an avenue in which pest and disease can get inside the
trunk of the tree and can cause harm to the trunk of your tree.
Okay, so, I'm done wrapping the way up this tree. I did wrap a little further up
this tree than some of the other trees. The main point is you want to try to get
as much of the trunk area protected as possible. You could wrap some of these
limbs as well if you chose to, but I wanted to make sure since I had so much of
this exposed trunk that I got wrapping on the majority of it. Typically people wrap
up to where you start to get the start of the majority of your limbs.
If you have several branches in the same tree or shrub, don't be afraid to just
wrap around all of those branches in this type of a form to get the same protection
that you would for a trunk of a tree.
One reason for having a mulch layer to protect trees is to avoid an injury like
this, and this was most likely caused by a lawn mower or weed whacker running
into the trunk of this tree. You can see this is a fairly severe injury to this
tulip tree here. So a layer of mulch helps to keep the lawn mowers and the weed
whackers away from this trunk area. Also the mulch is really wonderful because it
is a layer, a protective layer in which the tree does not have to compete with
grass to gain access, so it really provides a year-round reservoir of water
for this tree. Also in the winter time the layer of mulch acts as almost like an
insulating blanket. It really helps to moderate or stabilize that surface
temperature of soil. So all of those reasons really make mulch a great
solution for protecting your trees and shrubs from landscape.
The mulch layer should ideally be somewhere in the range of about two to
three inches thick. It doesn't have to be thick, and it's really wonderful if you
can bring that mulch layer all the way out to what we call the drip line of the tree.
We have this really beautiful Northern Catalpa here, and the drip line actually
follows where the leaves end, all the way around the tree, so this large circle
around the tree, and as water drips down onto the ground, this is where the
majority of the feeder roots are for the tree that bring up water and nutrients
that help supply this tree. So here we have a very good mulching job where we've
got about two to three inches of mulch, it's brought all the way out to the drip
line of the tree, but there's one other thing that I really wanted to show you
that's very important when you mulch a tree or a shrub in the landscape, and that
is that you want to make sure you pull that mulch away from the base of the tree.
This tree is mulched correctly because as you can see the trunk of the tree comes
down and at this very base here, we see that the roots are starting to flare out
into the ground. That means that this tree was planted correctly because it was
planted right at that root flare. You see that in older mature trees with the trunk
that comes down and then they flare at the ground, and then also when we put down
our mulch we want to make sure that we don't have the mulch covering that root
flare, we'll leave that open.
Here's another tree and I hope that you can take just a second to look at this
mulching job and to see the problem with it based on what we learned from the
previous example, and many of you may notice that the mulch is much much too
high on this tree. The tree almost looks like a popsicle stick coming out of the
ground you don't see any flaring right at the bottom and in fact we have almost what
we call volcano shaped to the mulch. This mulch is resting too high on this trunk
so if I wanted to correct this situation I'd go ahead and I'd pull this mulch back,
you can see I'm really pulling away quite far.
We want to keep digging.
See how deep that was buried? It's hard to notice that until you really get in here,
and you dig down and you look for that root flare.
You can see how deeply that was buried, the root flare was buried, and that's
very difficult for the tree so whenever you're doing your mulching job you want
to make sure that you always find that root flare and that the mulch comes away.
If you were to leave the mulch up against the trunk of the tree like this, this
would present an avenue for pests and disease to access and get into the tree
and it could eventually act as a detrimental effect to the health of the
tree so it's very important when you are mulching that you do it correctly.
Another really important thing to help protect your trees and shrubs during the
winter time is to make sure that they're
well watered in before the dormant season hits.
And I wanted to just show here a really easy and inexpensive way to water a tree
this is an inexpensive soaker hose you can buy these at most yard and garden stores
for somewhere in the range of $15.
I can hook this up to my garden hose and just barely turn it on to a trickle,
and this will give this tree a nice, slow
water. I want to leave that running for a long period of time, you can leave it for
a couple hours. It's not a waste of water at that point because you're barely
turning that water on to a trickle.
It's just that it's giving this tree a really nice, deep water.
Again, I'm putting the soaker hose down around the drip line of the tree, and with
that water combined with this wonderful layer of mulch here it's really going to
give this tree a good water before the dormant season hits and the ground freezes
Okay, we can rest easy that now our trees and shrubs are taken care of for the
winter time months. In summary, we have the nice layer of mulch that's placed at
the base of the tree, you can see that the root flare is exposed and the mulch is
gradually sloping out to the drip line of the tree. We have our trunks wrapped in
the white to help prevent against sun scald or southwest injury, and we've used
the soaker hose to give this tree a nice water in before the ground freezes for
the winter season. It's important to note that this isn't the best time of year to
fertilize your trees and shrubs, go ahead and leave that for early spring, and it's
also not the best time of year to do any significant pruning.
Any limbs that are diseased or broken can be pruned off at any time of the year, but
this isn't the time of year to be doing pruning on your trees and shrubs.
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