Can mulch kill my moringa little plant?

Hi, i used to have 3 little moringa plants, 2 of them were multched with grass and a little bit of leaves from molle (schinnus molle) in order to repeal the ants. But one of my moringa just had very few mulch.... so one day i was in a hurry and i just put a bunch of dead leaves and plants that i cut days before ( withouth knowing which plantes were those). The problem is the after 2 days i came back to my land i i found that little moringa plant dead!!!
So i was wondering, what did kill my moringa plant? are there are herbs and short plants that can be poisonous if used as multch?

Hi Ronaldo

Yes! Mulch can kill moringa if it causes too much moisture around the stem. The good news is that it can also look like they're dead, but the root is fine and they grow right back. So don't dig it up just yet, it's pretty likely to regrow.

In general, I had really high hopes for moringa, especially hearing how hardy it is. What I found in our climate was that it absolutely needs a good amount of time when it's protected from wind/rain/critters. Last year I planted about 20 moringa in the soil at about 2-4 months of age-- only one survived. (I also sowed about 20 seeds directly into our food forest-- all got eaten very quickly!) I kept one moringa in a pot until it was about 9 months old before planting, and then planted it about 6 months ago, and it is doing very well. This year, I'm keeping the moringa in pots until next spring (about 1 year)

Cedar and other growth inhibiting plants may cause issues but usually require being tilled into the soil, can't say for sure if any plants are poisonous. I used regular grass clippings from the lawn to cover up my moringas for the winter, the only green parts left are below the height of the grass where the bugs, snails, and frost can't get at them. They all look like dead sticks but should sprout back up in the spring from the green part/root ball thing. The plants in pots are a different story, tiny dead sticks but barely alive at the soil level.