Cover Crop on thick mulch

Last spring I put up hardware cloth mesh rings around the base of my fruit trees in hopes to reduce weed and sucker growth very close to the trees.  I found that many of these had weeds and a few suckers also.  I am now trying an old idea of using thin wall corrugated pipe rings around the trees. Had to special order this large size and I cut them 12 inches long and a slice down the side so they will (hopefully easily) warp around the trees and last a couple decades.  
I had pilled up mulch around the trees and so far have 12 inches that have decayed back to maybe 6 inches and will add some more over the winter.  I also started growing comfrey around the trees and want to scatter some more cover crops.

Will burying the comfrey be ok being buried maybe 6 inches?   Are there any arromatic and predator/pollinator attracting plants that I can plant now or even just before last frost?  I want t scatter them on top of this thick mulch and am not sure if any will grow in just chips or through a thick mulch.

I am trying to figure out a way to reduce the workload for maintaining a orchard and soon to be food forest.  Looking at as many perennial plants as possible but reseeding is good too.  I live in a suburb so don't want angry neighbors with invasive plants spreading.

Dennis,

That is established comfrey, right?

Now that I have established comfrey, I have come to learn what all growers of comfrey eventually know:  you can’t stop comfrey!!  I think it would laugh at the idea of 12 inches of mulch!!  I don’t think it would care if you dumped 2 feet of gravel on top (but I don’t suggest it).

I say go ahead and dump those 12 inches of mulch around the trees, I am sure the comfrey will be fine.

Eric

Dennis,

If you were really feeling ambitious, I would do the following:

1). Lay down cardboard of a thick layer of paper around the tree to act as a temporary weed barrier.

2).  Pile on that mulch!!

3).  Get some wine cap spawn and mix into the mulch.  

Doing so would give you weed protection, the comfrey will eagerly grow through, and the mushrooms will over the course of the next 6 months to 2 years give you wonderful, fertile mushroom compost !!

I now love adding mushrooms to my gardens and it pays real dividends.

Eric

Eric,  I live in fungi land.  The current layer of wood chips is already like walking on a carpet with a pad underneath.  I can dig away a couple inches and find white or orange strands of mycelium.  But this also means I live in bug paradise so I grow only cold weather varieties of edible and medicinal mushrooms.  That reminds me to go harvest my shiitake off my logs.  thanks

On word of warning here, do not pile anything up close round your tree, that's a good way to kill the tree. general advice is mulch should not be closer than 1ft from the tree's trunk. On website with advice

Also if you are getting suckers are they grafted trees? If so piling mulch up round them and burying the graft will encourage the tree to root on it's own roots, undoing any benefit the root-stock is meant to be providing.

Dennis,

Well if you have all that fungi there then in my opinion you are ahead of me.

BTW, if you want to lay a cardboard layer, I would cut little holes for the comfrey to grow through.

Eric

Not sure if that corrugated pipe is for trunk protection or is a water conveyance to the tree from a gutter or French drain. If it is for water, it would be better to have it at the drip line rather than so close to the trunk (along with piled mulch this could cause roots or bark to rot).

If you want to get rid of that comfrey, just cut it low to the ground, scrape the mulch back from the base of the plant, and then put a bucket or flowerpot or some other covering over it, making sure that there is no light that gets to it.  Then pile the mulch up next to the bucket/covering.  Leave it for 6 months.

Done.

Ben,  THe pipe is to go around the base of the trunk like a tree ring.  THey are a foot long and I am hoping that this is enough heavy shade to prevent growth inside the pipe but also allow moisture to evaporate.  

Denise,

When I was posting I was doing so on the assumption that you wanted the comfrey to survive the thick layer of mulch.  Was I correct?  This is what I would personally want.

Eric

Oh yes.  THe pipe is to prevent a mulch volcano and also stop weeds from growing around the base of the tree.  The comfrey will eventually prevent weeds also since it is such a fast growing plant.  I was just worried about killing the comfrey by burying it with another layer of wood chips on top.

Hello Dennis, as Eric says, the comfrey will survive as much mulch as you can throw on top of it, it is tough as old boots. We put drainage coils around the trunks of the fruit trees at the community garden when the trees were first planted, having placed a thick layer of cardboard down first.  It was as much to protect the trees from being damaged by over zealous weedeaters coming too close. The weeds have still managed to grow inside the drainage coils and need to be pulled out regularly. We haven’t bothered with the coils when we plant new trees now, just put down cardboard around the trunk and each time we top up the mulch, place a fresh layer of cardboard around the tree trunk.