Xtremehorticulture

Xtremehorticulture of the Desert

Mesquite Does Not Normally Develop Extensive Shallow Roots

Leave a Comment / lifting cement, problems with sidewalk, removing, surface roots /

Pic of native mesquite I took in Jerez, Mex., showing sinker roots. Q. I am a member of the Mesquite Club (est. 1911).  Our clubhouse is at 702 East St. Louis.  The patio concrete is fractured in many places and we are in the process of replacing it.  Inside the patio from St. Louis east side is a large mesquite tree (app. 50 yrs. Old).  The first concrete block is raised on the west side.  It has been suggested the tree is to blame and to remove it.  I spoke to concrete contractors and they felt the tree is not to blame. We have an underground stream in the St. Louis area that may have caused the problem.  The contractors, when removing the concrete, if roots are present, they will remove them.  A local nursery was contacted and said a mature mesquite tree’s root system would be the size of the tree’s canopy.  The tree is highly thought of and adds to our curb appeal.  Your advice would be appreciated.  A. Nice to hear from you and from your historical club.  The roots of mesquite can be highly variable.  In the desert they have been traced down to over 150 feet in depth.  These are trees located close to a perennial rivers in the desert running through arroyos.  Their root system is generally a three-tiered root system when grown naturally in the desert.  The first tier, or surface tier, utilizes water close to the surface after rains.  This is the easiest water for the mesquite to utilize and will expend very little energy to use it.  As this water disappears, deeper roots go to work in extracting water from greater depths where it still can be found. After extreme periods of drought, water may still be extracted from even greater depths.  Dont remember the tree any more but not mesquite. surface roots. When we grow mesquite in urban locations we seldom water them deeply.  Because of this, their roots tend to be a shallow and never develop their deep structure.  It is possible the roots may be the problem but you will not know all until the cement is removed and the roots located.  Generally speaking I normally do not find tree roots to be a problem with lifting cement slabs or sidewalks if there is at least about 6 feet of open space between the tree and the concrete.  There are exceptions with mulberry being one of them due to its large number of surface roots.  Desert trees normally don’t cause these problems but if the tree were watered with shallow irrigations and there was a lack of oxygen deeper in the soil, then the roots would tend to grow on the surface and be a problem.  I hope this helps. There are some possible alternatives that you might consider if you are keeping the tree.

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Italian Cypress Dying in Same Spot After Three Attempts

2 Comments / construction debris, landscaping, poisonous soil, toxic soil /

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

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Oleanders Not the Health Concern That Many People Think

Leave a Comment / heart problems, poisonous plants /

Petite oleander growing in rock mulch. They do nicely in rock mulch. Q. Saw your article in the Southwest View. My association has several petite oleanders. I like them and they are very pretty and hardy and never have to replace them. Some people with allergies and pets think they are very poisonous and bad for their allergies. Just how bad are they and will they kill pets???? A. I personally love oleanders. Yes, they are poisonous along with hundreds of other plants in our landscapes. If we tried to outlaw all the plants that are poisonous we would not have much left to use for landscaping. As far as animals eating the oleander leaves, I think this is a bit stretched. There are some reports in California of suspected animal poisonings from oleanders and it is probably not a good idea to have them close to livestock that eat landscape plants like any other poisionous plants. Closeup of salmon colored flowers of this petite oleander. Oleanders have been unfairly treated in my opinion. They do not cause heart problems due to their pollen as has been reported in anecdotes. I remember back in the 1980’s there was a cardiologist in the Las Vegas area who tried to have them banned claiming that they caused heart problems. But this was an overzealous physician who based his opinions on his opinions, no facts were involved. I remember that we (the University) challenged his position with hard science and his proposal was turned down by the government officials that were approached about their possible ban. If this opinion is flairing up again then it needs to be challenged with research documentation that this has been proven in peer-reviewed research published in scientific journals. I doubt anything has changed. Oleander pollen is heavy and sticky and not carried by wind any considerable distance at all compared to plants like olive, pine, mulberry and many, many others which we know do cause allergy problems. Poisonous, yes. Contribute to health problems? No. Prove it differently.

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