Be careful of over mulching your plants.

More is NOT better when it is more than 2 or 2.5 inches at
MOST!!!!

Sometimes people ask me to advise them because their plants seem
to die one at a time. One after another after another aftyer...
That's terrible! They report that they have watered and mulched
their plants and followed instructions for to the best of their
abilities.

How might I help? Well, when plants die one at a time, that is a
different symptom than when the plants die in a group. Either
"issue" has a definite source, right? We both want to know the
answer and prevent repeating the problem. Even when I didn't
sell the plant, I don't want it to die, and I don't want to see
its owner dissatisified either.

Now, what is the cause of the plant's demise? Sometimes it can
be the mulch. Look for tip burns on plants. Tip burns can be the
result of esterification of volatiles in cedar mulches. If the
mulch had not sufficiently aged before being used as a mulch,
this could be the problem. If it appears to continue, I'd
suggest that you remove the mulch. You can use it next year so
stockpile it, then reuse it again. You must be able to address
problems before the plant declines to the point where it is
stunted or doomed. Mulch can act as a barrier to air flow to the
root zone. Thus limit the amount of mulch. Remember that mulch
is like asprin. One or two (inches or tablets) is what the doc
recommends. If you use 10 or 15 you too may die. More is not
always better. Poor quality mulchs can also contain plant
pathogens. Well composted mulches that have a heat history
should contain less pathogens. For this reason I try to use
mulch sparingly.

You can see more aticles and information about plants at
http://www.seedlingsrus.com