zone 5, 1 vine, concord grapes, flat, windy, full sun, plenty of moisture through the spring (that is probably the biggest trouble i have with the clay/heavy soil).
it's about 20 ft from an east drainage ditch which runs all year. and about 5 feet from another trench that i just finished digging the River Nile (the south drainage ditch) down another foot and a half (and widened it too) so that will help keep that whole area a bit drier. that is about 3 feet deep from the level that the vine is at.
i cannot ammend the soil or build it up more as this is an established vine (well i could probably drill some holes and ammend that ways, but it would take years to make much difference) i think taking the drainage down another foot and a half will do as much.
in the past the vine was left in a heap on the ground, it was run over by a truck, mowed, and otherwise ignored. it grew fine and even had nice fruit in bunches without rot. not a ton of fruit, but no troubles with anything else.
then the formal gardens came in, and i thought a nice arbor to climb would be nice for it and all was good.
except it wasn't.
the surrounding area was covered with black plastic (to keep down weeds) and then the black plastic was covered with slats of wood to hold down the black plastic (not my idea, i hate plastic mulch).
the formal gardens also had plants added, some which brought and harbor rust and black spot fungal diseases. mulch, hollyhocks, roses, and rhubarb, which i thought didn't have troubles, but sometimes it gets spots of rust on it. only noticed it last year and this year.
then the black rot started taking out all the grapes. most of them started turning purple/brown and falling off before summer would be through. i think that came in heavy when we tried to get roses to grow in the clay (and used wood chips to mulch them). the roses are gone, the fungus just jumped ships (or chips to be more accurate).
i thought that perhaps the black plastic and wood slats were harboring the fungus spores from one year to the next. so last fall we took all that up and i buried the wood (which was heavily rotted anyways) and we threw away the black plastic (as it was heavily rotted too from sun exposure). and we stirred the dirt some to get at some of the weeds (raspberries and horsetail) so that gave the sun, cold, etc. a full fall/winter/spring to kill off the spores, but i figured there would still be some. i didn't spray the vine. i probably should have.
except this is clay, so the spores are probably quite happy there for a while yet...
only reading later (after it had already started growing out this spring) did i see that i probably should have sprayed it when the leaves were done and off. i pruned it severely as usual.
sure enough this spring was wet and long, we also had a late frost which left some dead leaves on the plant, the black rot came back a little, but i was hoping that the sun and air would take care of it as soon as it got hotter. well it isn't as bad as it could be -- it is still there. now along with it i have the remains of brown spotted leaves. this is a new trouble. hmm...
today i went out and removed as much of the black rot and the spotted brown leaves/stems as i could. there is enough healthy other leaves and it will have plenty of time to put on more growth (i probably removed half the mass of the plant -- it is a very healthy vine otherwise -- it really wants to produce and always sets a heavy crop but then i lose most of it). i thinned out the heavy areas to let more light and air get through and then i sprayed it as best i could with bordeaux mix (copper sulphate and calcium hydroxide) to knock the fungus back. we are due for some rain and my reading says that this is a good time to apply (you'd think not because the rain will wash some of it off but it will at least help keep some of the fungus from getting going again in the new moisture). and it has been higher humidity lately, so i suspect that is not going to help.
the good news is that there is plenty of leaves that have no sign of rot of any kind, so i think i may get some fruit to ripen.
ok, all that history and finally some questions:
i'm still getting flowers on it (this has been a crazy weather year that is for sure) will there be enough time for them to ripen? our first frost date here is probably around mid Sept to early Oct. or should i prune them off?
i imagine i will have to keep spraying fungicides on it until the spores finally burn out in the surrounding area (and those on the plant itself which are in the crooks of the branches and the bark). am i in for years or will things ease off next year if i spray more this season and once the leaves fall off again?
i'm hoping to keep the spraying to the elementals (copper sulphate, dusting sulfur, etc) and spot trim what i can out if it seems to stay local. should i spray the surrounding grassy areas and along the ditch too? that seems excessive, but there are wild grapes growing there (quite happily it seems as i have to keep fighting them off). it seems rather intense to spray so much but i'd like to be able to actually get more than a few bunches from this vine.
i may have lost the war this season by starting spraying too late, but i hope it will at least help knock it back for next year and beyond.
also, i'm getting some fading in some of the leaves, there is no curl or other signs of trouble, but i'm thinking that it is a natural reaction to having the black plastic removed and having a large part of the root system suddenly having to deal with a whole different environment (hotter and dryer since it is now exposed to the sun) and it will have to figure it out. if we get no rain tonight i will have to water it good tomorrow...
sound reasonable as a conclusion?
another idea was to plant a new vine of something more resistant to fungal problems, but i'd be planting it in the same location and there would be an overlap -- it would have to be resistant enough to overcome the already problematic area. i don't think that would work, but i consider that the remote approach if spraying for a few years and keeping a closer eye on things doesn't help matters.
anything else obvious i'm not seeing here (besides giving up on this vine completely?). i can't really start over some other place on the property with the current layout.
thanks for your insights, heckles or otherwise random comments. :)
if you managed to make it all the way through that without wanting to take a nap congratulations! you must be a gardener... :)