Hi, Bob
I haven't grown Moreas, and don't garden in your climate, so
have hesitated to respond.
>Does regular fertilization shorten bulb or corm life?
Normally, fertilization supplements, not replaces, what your
soil can already provide. Bulbs (and other plants) usually grow more
lushly, enough so that they are more subject to pests and
diseases, and to that extent, fertilizer can lead to shorter bulb life.
>I worry that this artificial forcing may wear out the
>bulb. I have grown moraeas in pots for 15+ years
Do you repot (provide fresh compost) on a regular basis? As far
as forcing, fertilizers don't really force anything but lush growth.
As a general rule, I use minimal amounts of fertilizers, but for containers,
my experience is that a regular but weak (half strength or less) application
of fertilizer during that plant's growing season, is necessary for plants
of all
sorts. Keep in mind that I use containers for many of the seedlings I grow,
and they do better with higher levels of fertilizers than older plants. I also
garden in a climate with a lot of rain, and nitrogen is easily washed out
of the soil.
I don't think bulbs "wear out", but they may gradually acquire
various pests and diseases that debilitate them. Viruses for instance
do kill some bulbs outright, but more often the afflicted plant simply
doesn't grow as well as it could, and becomes more susceptible to other
pests and diseases, which may eventually kill it.
Ken