Not at all sure what "B1 treatment" consists of, although it sounds scammy to me. No, your first answer was the correct one-water management. There is nothing else for you to do, no matter how bad you may want to. But paying attention to soil moisture will be important in the weeks, months, and even years ahead.

Nothing you can do now will compensate for cutting all the roots off on one side. What is left to do is watch and see if the trees die, cut them down if they do.

Thanks. Unfortunately it was a project we had to do because of a drainage problem. This area is sloped towards our patio and creates a very large pool of water every winter and then rots the posts holding up the patio and other problems. No drain has worked and the street is too far and would require ripping up concrete and so forth. The previous owners were idiots and angled everything towards the house.

When I said "B1 treatment" I meant hitting the area with some waterings that include B1 for root growth.

Vitamin B-1, aka thiamine, does not reduce transp

lant shock or stimulate new root growth on

plants outside the laboratory

https://puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/vitamin-b1.pdf

Thanks. Great article. Would sealing the large roots with a tar type sealer be beneficial? I assume it would help in root rot, but have to ask.

Covering wounds with traditional sealants inhibits

oxidative processes, which in turn will reduce

callus formation and subsequent compartmentalization.

https://puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/wound-sealer.pdf

Again, thanks. Glad I did ask.

This area that we had cleared sits a couple inches below that of the cypress trees, so the roots that were cut will be butt up to a hard border, something like a cement paver. If this gives you a better picture is there anything more you'd like to add? And should I mulch over the top of the cypress area to help retain moisture? If so, would wood chips be okay or am I asking for a termite problem and then an additional root problem?

I wouldn't worry about it right now unless you are in drought, then I would worry about water.

Thanks for everyone's help.

what you should do.. is plant some new trees ... so when this one dies ... and it probably will .... you will have unaffected new plants.. well established ...

trees do their thing in tree time.. and that is counted in years or decades ...

they say a tree is twice as big below ground.. as that what we see above... if you significantly impaired half of its root mass ... well .. its going to suffer .. whether it will recover.. is left to fate.. and time ...

it is stressed... not hungry .... no fert ... and really .. nothing else you can dream up ...

there is not much you can do .... other than watering properly ... deeply and infrequently .. to try to regrow the root mass ... to offset the damage ....

ken

gynot, mulch is almost always beneficial. There is nothing about this situation to change that. And yes, wood chips are just fine. I personally don't believe the use of such contributes to termite problems...........in most cases.

Ken, I live in a 9b in SoCal which of course has been dry. Deeply I get, but "infrequently" meaning say 3x a week? Also, this is such a tight area that there'd be no place to plant new trees in addition to the old ones.

wisconsitom, the only reason I mentioned termites is that a few months ago I planted a tree in my front yard and surrounded it with chips. Once a week I have to pluck grass from that area. When doing so I see little bugs that resemble either ants or termites traveling around with bits of something white in their mouths. BTW, the tree, a Queen Palm, is doing great, but again these bugs are a concern and why I don't need additional problems with the cypress,

Sounds like ants. What do they look like? Are they inside the mulch only? Termites are pale and don't come out into the light except when the flying stages leave the nests to start new colonies. Or the nest is under attack, being dug up or torn open.

When doing so I see little bugs that resemble either ants or termites traveling around with bits of something white in their mouths.

Sounds like Argentine ants, which are moving larvae of more ants, which is what they do when disturbed. Southern California is one giant Argentine ant colony.