Xtremehorticulture

Chinese Pistache Growing Poorly

Q. A nursery planted my tree in spring (May I think)
it has sap running in several places from the trunk. Also the leaves seem to have some disease,
but the new leaves at the base of the trunk look great.  I have looked on the internet but could find
an answer.  It looks like it’s
dying.  What is your prognoses – see
attached photos taken today.

Trunk of this Chinese Pistache
A. I looked at the pictures of the pistache tree that you
sent to me. The pictures make me think it is water related. Your Chinese
pistache is probably a grafted tree. A graft is used to attach two plants
together; one which will become the roots and the other becomes the trunk and
top of the tree. If you look at the trunk of the tree a few inches above the
soil you should see a slight “crook” or bend in an otherwise straight
trunk. This bend is where the graft took place which joined the two young trees
together.

Picture of leaf sent in

This is important to find. If the new leaves you
mentioned at the base of the trunk are coming from below this crook or bend
then the tree is “suckering” from the plant grafted for the roots.
This is a very good indication that the top part of the tree has been damaged
or is under a lot of stress. Normally, this is not a good sign and you don’t
want this type of growth to continue. You would remove this growth from the
trunk and is close to the trunk as possible. If you leave any short stubs after
you remove these suckers then growth from this area is likely to return.
Base of trunk showing new growth
What caused this? This is where I go out on a limb, no
pun intended. Nine times out of 10 this is related to some sort of watering
issue. I am going to guess and say it’s not getting enough water. If this was a
24 inch boxed tree you should be delivering about 15 to 20 gallons of water
each time you water. I am guessing this tree is on drip irrigation. I can’t
tell you how many minutes this would be because that will depend on how much water
these emitters are delivering. A tree of this size should have a minimum of
four drip emitters spaced in a square pattern about 18 inches from the trunk.
If I am correct, you should be able to correct this problem by building a basin
or bowl around the trunk about 3 feet in diameter and 6 to 8 inches tall. You
would use a hose and fill this basin with water completely once a month during
the winter months. When things begin to warm up in about March you might do
this every two weeks. Once you hit may you should be doing it weekly.
Chinese pistache shown in its location
Another possibility could be that it is receiving too
much water. If you are watering daily and delivering a lot of water through
those drip emitters than it is possible the roots are suffocating because of
too much water. I tend to believe it’s not enough judging from how the tree
reacted.

What to do? Build that basin around the tree that I
mentioned earlier. Fill this basin with water from a hose twice. Remove the
suckers from the tree as I described. If you think there are not enough
emitters, add emitters around the tree or find some way to deliver a higher
volume of water if you are only watering a few minutes. You won’t see much of a
reaction from this tree to these improvements until next spring and summer.
Remember, do not water daily. When you do water, give it a lot of water and
wait a few days between irrigations during the summer months.

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