!!!!!!!!! What is killing my shrubs?

I planted some haskaps, aronia, currents, raspberries, hazelnuts and other herby stuff a few years ago trying to get a little forest garden going.

I got this big old black current bush from someone who didn't want it anymore and planted it.  One year I got a ton of woodchips dropped off and did the cardboard / woodchips thing everywhere between all the plants.  Maybe later that year, or the next year, the big black current plant started dying; leaves turning yellow, orange and dropping off until dead.  Then the same thing started happening to the aronia bush next to it.  I thought "hopefully this sorts it self out" and left it at that.

Next year or two the disease is spreading more.  I lose more aronia, a hazelnut drops off, as well as a pea shrub.  Now, haskaps are getting it and other smaller currents.  Some comfrey is looking rough too.

Basically since the disease has been killing stuff, I have left the area alone.  Other than coming in with the weed eater hear and there to open things up around the plants.  I have attached some pictures here of where things are right now with haskaps, aronias and currents.

Any help on this would be appreciated.  I don't want this moving to other things in my yard...

Wow! That's really sad.

Could it have been something in the wood chips rather than a disease?  I don't know herbicides but maybe one that kills woody growth?
Is it just the woody bushes damaged and not the other green plants growing around them?

reread and saw that your comfrey is affected also.

I forgot to mention that it seems like the "disease" is spreading out from that old current bush which died first.  

Hi Simon,

Sorry to hear about all this - it sure can be frustrating...  As I read your post, a few questions came to mind.

Were you successfully growing anything in this area, prior to a few years ago when you initiated plantings there? If not, possibly a soil deficiency there that had not been evident yet. Or as you may be supposing, there could have been toxic content in the woodchips that were brought in to mulch the area. Testing the soil collected from several spots in that area, both for minerals plants need (are your plants starving to death?) and for contaminants (are they being poisoned?) could point out a clear problem to solve.

My go-to approach when a grouping of plants appears to be failing is mycoremediation (repair toxins, provide nourishment and strengthen the plants). Break up spent mushroom growing blocks and scatter around the plants, cover with a few inches of mulch for short term help, water well and regularly, and give the mycelium a season to work.  You can read more about this approach here: https://ambrook.com/offrange/environment/mushrooms-will-fix-your-soil
I also use a mycorrhyzae product called 'Recharge' - a powder that dissolves in water: https://realgrowers.com/product/recharge/
And I usually add SuperThrive for nutritional support (vitamin B1 and kelp) to the same water: https://thesuperthrive.com/

What do the roots look like on the plants that are dead / most impaired? Are voles, meadow mice, pocket gophers or other burrowing varmints eating them? Or weevil larvae eating current plant roots? They likely would not bother the comfrey, but they sure can destroy the other plants you mentioned. Mycoremediation and adding nutritional support for the plants won't solve this problem. Introducing some gopher snakes could help with a varmint problem (seems like so many times, the options for solving a permaculture problem involves "What eats this?") Interplanting / companion planting garlic, onions, chives, sage, etc that the varmints dislike but provide benefit to your plants could be an option.  Maybe it is time to dig up one of the mostly dead ones to take a look at the roots.

Good luck with it!

Thanks for the thoughtful reply.  I will do a little investigating on the roots and look into soil testing options around here.

I have black walnut trees nearby that are 35 years old.  Otherwise it was just wild grass land growing.  

I built a hugelkulture in the area too with dead pine logs. There is almost certainly critters living in there.