Italian Cypress Dying in Same Spot After Three Attempts

Not the readers pic but Italian cypress dying next to each other

Q. I have a walkway about 5 feet wide, from the curb to the front door.  Approaching the entrance but not near the building, there's an Italian Cypress on either side of the walkway, simulating pillars.  One of them is lush and almost as tall as the 2 story house.  It has been in about 4 years. On the other side, the tree died after maybe 2 years in.  I watched it closely... how it died from the inside - nearest the trunk - out, and more so on the sunny side.  I had a tree expert out to access it... we tried Bayer systemic to no avail...  so we took it out and replaced it, and this time I had to get a more mature tree to match the other one. I simply can't believe it... the new one is dying to!  It barely learned to stand on its own (without its stake), and now it's dead!  There's something about the spot !  I'm amazed that whatever it is hasn't jumped over to the other tree!  It must be something there, in that spot! 

Please help me.  Do you know who and/or where I can send or take a sample of the soil from under the tree (when we take it out) and a sample of its roots so a scientist can #1, look at the soil under a microscope and

 Another problem thought to be associated with overwatering It cypress. Branch droop.

see if they see anything that's causing this; and #2, look at the roots and see if they detect some disease that 's causing this...  maybe that the trees are contracting from the soil?

My heart breaks when any  tree dies...  but these are so essential to my facade, and I love Cypresses; at Christmas I put twinkling lights on them,  ...they just bring me so much joy, and this is such an unimaginable freaky curse of a problem...   and now, I'm going to have to invest in a special ordered, really huge and lush tree to match the other one, and if I don't discover what's killing the tree in this particular spot, the new one will die too!  Imagine, if that happens, I'll have to give up and chop down the huge, beautiful one I've had from a little 5 or 6 footer 'cause the entrance looks dopey with one big Cypress on one side....  :(   !!!!!

Please don't think this has anything to do with spider mites...  I have learned all about spider mites...!  (Back about 1988 (in a different house) in the winter when you don't look at your plants that much, I finally noticed that my Cypress trees were completely embalmed in spider web!!!    ...I thoroughly washed them with dish soap and, of coarse, rinsed them well, and they survived...!  :))

When I noticed this one dying a few months ago, I washed it and washed it; I figured if it was something on the tree I might wash it away, and if it were something in the soil, maybe I would flush it away...  then I poked deep holes to give air to the roots...  it has just kept dying.

Thank you so, so much for anything you can do to help with this... 

A. Yes, it is possible there might be something in the soil remaining from the construction of the home.  If that is the case the it would be much cheaper to dig out the soil and replace it down to a depth of perhaps 2 to 3 feet in the planting area. 

To have a soil examined for an unknown problem would be terribly expensive and you would probably learn nothing.  So if you are this concerned there is something in the soil, then replace it. 

Let’s assume that your soil is fine.  If an entire plant dies then the problem is either in the soil, the roots, or lower trunk.  Then it might have something to do with how the plant is managed once it has been planted or even how it is planted.  I do think you could plant a smaller tree and through some pruning over the next couple of years they could become matched fairly well.

Planting.  Never allow Italian cypress to be planted deeper than it was in the container.  Don’t dig the hole deeper than you need to in case of settling.  If existing soil is piled around the trunk of the tree or even a wood mulch and kept moist it can rot the base of the tree causing what we call collar rot and very quickly die, usually in the heat of the summer.  When the tree is removed, the trunk of the tree at the location where it enters the soil will be brown and rotten.  This is not easily seen unless a trained eye is looking for it.

Once disease organisms causing collar rot have attacked plant roots and the lower trunk in a spot, the disease organism can be a big problem for plants put in the same spot. Some fungal disease organisms that cause collar rot (there are at least five) can be extremely virulant to the same or similar plants planted in the same hole.

Italian cypress can be very sensitive to soils which do not drain easily or are watered too frequently and the roots kept wet.  It might not be a bad idea to replace the soil and make sure that the soil being used drains freely after an irrigation.  This would eliminate that problem.  Any soil that you are bringing in should be amended with organic matter such as compost.

Irrigation.  Italian cypress likes to enjoy the wet winters and hot dry summers of a Mediterranean climate.  Water them deeply but infrequently.  Make sure the soil drains freely.  I would rather have them under-watered than watered too often. 

Make sure enough water is applied during an irrigation to wet the soil to a depth of 24 inches.  Do not water until the soil begins to become dry again.  During the winter time, you might want to water once every 10 days to two weeks.  Around February you would increase the frequency to once a week.  Around the first of May you might increase this to twice a week.  I do not believe you should water more frequently than twice a week, ever, unless these trees are planted in pure sand.  So, when irrigating, water with a large volume and then withhold watering until the next large volume of irrigation.

It does not sound like an insect or spider mite problem to me either but spider mites commonly become a problem during the heat of summer, not during cooler or winter months. Spider mites may or may not cause webbing AND there are spiders that cause webbing in cypress without causing problems... in fact, these spiders can help keep the cypress free of some bugs.

A better indicator of spider mite problems is a "dusty appearance" to the leaves or foliage. This may or may not be actual dirt or dust. When spider mites become a problem during the summer months they leave behind hundreds of thousands of dead spider mites which appear like dust or dirt on the foliage. Frequently washing helps but sometimes you have to resort to chemicals unfortunately.