cedar trimmings for mulching??

I have been a mamber for less than 15 minutes!!
This is my question:
I have a bunch of mixed trimmings that I want to run through the chipper and it includes quite a bit of cedar.
My wife insists that cedar should not be used as mulch, as it contains chemicals that nature intended to kill off plants under cedars and thus decrease the competition for nutrients.
This sounds plausable, but I REALLY want to run the entire stack through the chipper!
Can I safely do this?
Mitch Black
Vista Ca.

Hi Mitch!

I have used mixed "shredded bark" from a small commercial place that did their own. I saw the brush pile that they made it from and a lot of it looked like what I call cedar... but is it really? Shrubby evergreen trees with flatten scales for "needles". But probably not the cedar of the southwestern desert/Colorado Plateau's cedar-berry producers...

Many plants -- while they are living! -- produce chemicals that discourage THEIR OWN KIND (or closely related) from growing too close, especially in harsh ecosystems. That is why when you look across the desert, the Joshua trees, ocotillos, or saguaros are spread out, and often +/- equally spaced, and the sagebrush, creosote, etc. in the understory, and down on your hands and knees the belly-flowers are doing the same! Botanists call it poikilotropism (or so I've been told, although I got no Google hits on the word). I'm not at all sure the effect lingers, at least not long, after the plant dies -- for one thing, that would work AGAINST the survival of the species!

Another thing that can go on is this: Any non-rotted organic matter will FIRST rob/use-up/bind the nitrogen in the soil -- possibly causing your garden plants to less-than-thrive -- but it's not actually poisoning them! Although that MAY be where the ideas get started about one type of mulch being bad for one or all other plants.

After or as the organic matter rots, it releases that nitrogen.

Now, if your plants that you want to MULCH are in good (which in all of So.California that I know, means IMPROVED) soil and/or you fertilize them appropriately, the mulch scavenging nitrogen from the top inch or so should not be a problem -- just don't use it as an in-the-planting-hole amendment unless composted (rotted). OR if you also add a source of nitrogen, at double or triple the normal rate... maybe.

Now, when I mulch, I'm usually more interested in keeping the soil cool and soft and absorbing of water, the weeds down, and the darned neighbors cats from using my garden as a litter box. If deep enough, your cedar-mix chips should do the first, and the second as long as you manage not to incorporate some source of weed-seed... some of the weed-discouragement may even be the nitrogen shortage -- at least as my bark rots-in-place, the weeds begin to encroach. Now, for the last purpose -- I scatter some peagravel (cats don't like it between their toes when they dig) -- have used anywhere from a pebble every inch or two, to one-two inches OF the stuff! i.e. sometimes I mulch ENTIRELY with stones.

Anyway. I welcome correction(s) on any and all written above -- I am not an expert, these are just my understandings. If someone knows PARTICULARS about cedar different from other organic matter, specifically other conifer-type "forest products", speak up! I just didn't want Mitch to think we were unfriendly here... thought I would start a little dialogue at least!

Welcome Mitch!
~'spin!~

There are also trees like black walnuts that exhibit allelopathy (not sure I spelled that right) which means that they emit chemicals that prevent other species from growing in their root zones, presumably so they can keep the nutrients to themselves. I've never heard of cedar doing this, but I'm definitely not an expert.

But crystalspin is right, any kind of bark mulch that's not decomposed is going to take nitrogen out of the soil, but I don't know that cedar would be any worse than other kinds of bark mulch that people use all the time.