Good luck! I dug around and pulled out a stump of a cherry tree that was a 9" caliper. Took 5 hours with a shovel, axe, pic axe, bow saw and pruner to get it out.

Roots take years to decompose ecspecially the large tree roots. I've come across roots of an elm tree that was cut down 12 years ago...the Cherry tree just grew around it. In fact there was a major cherry tree root that grew under the elm root and then went back up.

Part of my thyme and my oregano grow in a spruce stump. They are nice looking plants. Ash is not known to be allelopathic, so I do not see any problem leaving there as much of the root system as you can afford. I also have a hardy kiwi whose roots have entered another stump, also a spruce.

you might also do to it what I do to every stump of mine: go to fungi.com and buy yourself 100 spawn plugs of your favorite mushrooms. Use 40-50 on the stump, the rest on whatever main root you can uncover. You can do it right away if you can protect the stump from the cold (with a pile of dead leaves) for the first winter only (I also cover every plug with wax, you can just melt a candle).
No need to protect injected roots if they are underground.

If you are in a hurry to decompose the thing (it will still take years before it is fully composted), oyster fungi are the most aggressive decomposers amongst the edibles, in fact they are first choice even for bioremediation of grounds soaked with petrochemical products. It always works if the stump is recent enough, and they do produce big flushes for many years once the whole root system is colonized (about two years).

This topic has been covered a number of times here in this forum. A quick search might turn up some of the prior discussions. Some of the potential problems include disease, nitrogen depletion, drainage, and settling.

The fungi idea just might be a good one...lemonade from lemons...

thanks for the suggestions guys. I have tackled a small portion of the stump this morning and the main problem is that it is still wet and thus very spongy. When I sink the axe into it the blade just enters an inch or so but barely cracks the wood beyond the blade length. Hopeless, and it will only get more difficult as I get deeper.

With regards to the oyster fungi- what is the best guess as to how many years of fungi induced decomposition before a significant portion of the stump is eaten up and we could replant?

AND while we are at it. Option C is to build a planter over the stump (everything else- deck, planters, water feature- are raised around it) and plant a new tree. Problem is said planter would be limited to 2.5' by 2.5' and the whole point is to get a tree large enough to help block out a the eye sore of an apartment building on the other side of the lane way. 10' away on the same axis is my 8' tall Acer Palmatum 'Bloodgood' so ideally we would plant a taller specimen that would not conflict in height with the Japanese maple. Any suggestions for a tall growing (15' or higher), limited root ball specimen? I believe a variety of Caragana might be good for this application but from what I know they tend to be a little dainty and wont provide the screening we are going for.

Thanks for the help!

natural- i hope you will add your zone and location to your i.d. so people can offer you useful info!!!

acer negundo (my fav is winter lightning ), salix alba cericea, and heptacodium are all WICKED fast growers.
best,
mindy

Have you considered bamboo? Since the purpose is to screen the neighbor, I find bamboo to have worked for me. Fast growing, I installed a three foot deep barrier to control the runners. My bamboo is about 30 feet here in Boston, Ma
good luck
Tim