I'll start off with those of mine I can think of. Most have been MY fault,
but a few have been shortcomings based on 'pushing the envelope' too far.
Sea buckthorn - no go; guess they didn't like my clay soil and hot summer
"Pakistan" mulberry - planted with graft union below ground, in
anticipation of some winter kill. Killed back to ground 3 consecutive
years - even though they were relatively mild KY winters - re-grew 8-10 ft
each year, but no fruit. Well, actually, one year, we had a freak frost in
late September, it re-leafed and put out immature fruits, which got nuked
by the onset of actual winter a month or so later. After the last
killback, I dug it up, potted it up in anticipation of giving it to my dad,
in AL - but I have no idea what happened to it after that - it just
disappeared.
Grapes. - They just don't work for me. I don't know if the area(s) where
I've planted them are just too wet too much of the year or what, but
they're coming out this spring, and I won't be planting any more - unless
it's just to give some of the more cold-hardy muscadines or muscadine
hybrids a try.
Stonefruits - I've never been much on 'em to begin with, but my wife wanted
'em. Borers worked on 'em religiously the first few years - most didn't
make it through a second growing season. Borer pressure has evidently
dropped off on its own - most that still survive are 4-5 years old
now. Peaches, Jap hybrid plums, and pluots almost always break dormancy
too early and get nuked, though I have had a couple of years in which
Reliance or Veteran made a few peaches - most of which either brown-rotted
or dropped to the ground - I can't even get my wife & kids to make the
effort to pick a few peaches?! Green Gage is huge - trunk bigger than my
sizeable thigh; has had one branch that bloomed one time. I keep thinking
It'll do something, but not yet.
Figs - not really a failure, but I don't know if I'll ever get a fig off of
any of them. Winter-kill to the ground every year, then when they do set a
crop on new growth, they don't have a long enough season to mature before
frost.
First set of grafted pecan/hickory/hican that I purchased and planted died
at my hands - I fell prey to that old gardening misinformation about
amending soil in planting holes - guess I created a huge 'bathtub' for each
of them - only have two surviving members of that first group of ten.
Apples have been kind of hit or miss - planted way too many of them before
I came to the realization that I don't have time(or inclination, for that
matter) to do all the spraying that they require. So...as they slowly
succumb to fireblight, etc., I'm replacing them with pears and persimmons.