Q. I have a Museum Palo Verde and a crepe myrtle planted
in the Fall of 2012. The Palo Verde has
grown well but the crepe myrtle hasn’t grown much in seven years. The roots of
the Palo Verde are now lifting the stone ring I built around it. Can those big
roots be cut out?
in the Fall of 2012. The Palo Verde has
grown well but the crepe myrtle hasn’t grown much in seven years. The roots of
the Palo Verde are now lifting the stone ring I built around it. Can those big
roots be cut out?
A. Palo Verde
I will tell you about cutting the roots at the end but
let’s talk about your situation first. You have two different types of trees; the
Palo Verde is native to the desert Southwest and considered xeric (desert
adapted) while the crepe myrtle is native to the wetter and richer soils of
South and Southeast Asia. It is considered mesic and not desert adapted. You
can’t grow them the same way, under the same conditions, and have good results.
The Palo
Verde can handle the poor growing conditions of our desert while the crepe
myrtle must be pampered. Your crepe myrtle isn’t getting pampered that’s why
you have problems with it. These two trees are planted, managed and irrigated
differently.
Verde can handle the poor growing conditions of our desert while the crepe
myrtle must be pampered. Your crepe myrtle isn’t getting pampered that’s why
you have problems with it. These two trees are planted, managed and irrigated
differently.
The Palo
Verde will grow roots where water is applied to desert soils. If you water Palo
Verde 2 to 3 feet deep and let the upper foot of soil dry between irrigations,
the roots will grow mostly 2 to 3 feet
deep and not bother that stone ring lying on the surface of the soil. You
can control its rate of growth by giving
it lots of water occasionally and let the soil dry out before the next
irrigation. Every time it gets a deep drink of water, it will grow. When the
soil is dry, it does not.
Verde will grow roots where water is applied to desert soils. If you water Palo
Verde 2 to 3 feet deep and let the upper foot of soil dry between irrigations,
the roots will grow mostly 2 to 3 feet
deep and not bother that stone ring lying on the surface of the soil. You
can control its rate of growth by giving
it lots of water occasionally and let the soil dry out before the next
irrigation. Every time it gets a deep drink of water, it will grow. When the
soil is dry, it does not.
The Palo
Verde is more forgiving of desert soil even when it’s planted badly. I’m not
saying it was or wasn’t planted correctly, but it tolerates bad soils better if
they are amended before planting. The Palo Verde will look better if it’s
planted in decent soil at the beginning, but how and where you apply water will
dictate how fast it grows and where its roots are located.
Verde is more forgiving of desert soil even when it’s planted badly. I’m not
saying it was or wasn’t planted correctly, but it tolerates bad soils better if
they are amended before planting. The Palo Verde will look better if it’s
planted in decent soil at the beginning, but how and where you apply water will
dictate how fast it grows and where its roots are located.
You
can’t do any of those things with crepe myrtle. Crepe myrtle will not tolerate
soils if amended badly at planting time. It won’t like the hotter and harsher
locations in the landscape. But Palo Verde will. Crepe myrtle will grow much
better if the soil is continuously moist and covered with 3 to 4 inches of
woodchips. Palo Verde will like this too, but it can sail through desert
hotspots and poorly amended soils better than crepe myrtle.
can’t do any of those things with crepe myrtle. Crepe myrtle will not tolerate
soils if amended badly at planting time. It won’t like the hotter and harsher
locations in the landscape. But Palo Verde will. Crepe myrtle will grow much
better if the soil is continuously moist and covered with 3 to 4 inches of
woodchips. Palo Verde will like this too, but it can sail through desert
hotspots and poorly amended soils better than crepe myrtle.
If they
are both on the same irrigation valve, then you will have a problem because the
Palo Verde will get water when you think the crepe myrtle needs it. They should
be watered separately. That would be too often for Palo Verde. It will grow
shallow roots because its watered too often. If these trees are on separate irrigation
valves, then the Palo Verde can be watered less often than the crepe myrtle.
Using separate valves benefits both of them.
are both on the same irrigation valve, then you will have a problem because the
Palo Verde will get water when you think the crepe myrtle needs it. They should
be watered separately. That would be too often for Palo Verde. It will grow
shallow roots because its watered too often. If these trees are on separate irrigation
valves, then the Palo Verde can be watered less often than the crepe myrtle.
Using separate valves benefits both of them.
Can you
cut off the roots of the Palo Verde that are causing problems? You can remove a
few of them each year for the next three years but start watering the Palo
Verde less often and give it more water with each of its applications. Get its
roots deeper and out of the way. Apply water to at least half the area under
the canopies of these trees.
cut off the roots of the Palo Verde that are causing problems? You can remove a
few of them each year for the next three years but start watering the Palo
Verde less often and give it more water with each of its applications. Get its
roots deeper and out of the way. Apply water to at least half the area under
the canopies of these trees.
Crepe Myrtle
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| Readers crepe myrtle |
On your crepe myrtle, I would put a ½ to
one inch layer of compost 12 inches away from the trunk to about three foot
away. You can get it bagged from Viragrow. I think you will need about ten bags
or less. Concentrate the compost closest to irrigation water or drip emitters
where it will get wet and decompose faster and move the leachate into the
ground toward the roots. The tree will respond faster if you can auger as many
holes as possible around the trunk to about 12 inches deep and fill them with
compost. Spreading it on the top of the soil will work but it will take longer
for the tree to get the benefits.
one inch layer of compost 12 inches away from the trunk to about three foot
away. You can get it bagged from Viragrow. I think you will need about ten bags
or less. Concentrate the compost closest to irrigation water or drip emitters
where it will get wet and decompose faster and move the leachate into the
ground toward the roots. The tree will respond faster if you can auger as many
holes as possible around the trunk to about 12 inches deep and fill them with
compost. Spreading it on the top of the soil will work but it will take longer
for the tree to get the benefits.
Cover that compost area with woodchips
about three to four inches deep. You can get them free from the University
Orchard in NLV (N. Decatur and Horse Drive) or their office complex on the
corner of Paradise Rd and Windmill just south of the airport. Call their Master
Gardener helpline at 702-257-5555 and make sure they have the woodchips
available before you go.
about three to four inches deep. You can get them free from the University
Orchard in NLV (N. Decatur and Horse Drive) or their office complex on the
corner of Paradise Rd and Windmill just south of the airport. Call their Master
Gardener helpline at 702-257-5555 and make sure they have the woodchips
available before you go.
Then I would prune back the height of
your crepe myrtle and try to force some new growth lower on the trunk. Prune
the top back as much as possible while still keeping the growth on top. I am
hoping you will see some new growth lower on the trunk in the spring. This
growth will help strengthen the trunk and I am hoping you will not need to
stake it in a couple of years.
your crepe myrtle and try to force some new growth lower on the trunk. Prune
the top back as much as possible while still keeping the growth on top. I am
hoping you will see some new growth lower on the trunk in the spring. This
growth will help strengthen the trunk and I am hoping you will not need to
stake it in a couple of years.