When we purchased our house about 3 years ago, the yard had 5 stumps of trees that had been removed a few years earlier.
In lieu of grinding them down, now that they are starting to decay a bit, I was thinking I would plant something on top of each one with a pile of soil, if there are any plants that would send their roots down into the decaying wood. Blueberry bushes perhaps? Or something ornamental?
Has anyone done this? Does it work OK or should I just rent a stump grinder instead?
I don’t know if it’s a good idea, but I love the concept. I suppose it partly depends on what the trees were. I would think black walnuts would be a bad choice, how quickly are the trunks breaking down, etc.
I did this on the edge of my green belt. We had a 4-5’ wide cedar stump that had a hollow in it. It was very old looking. So I put a cedar in the hollow. We had grown it in a pot and used it as a living Christmas tree 5 years later. Afterwards I sank it into the stump.
All was well until this winter. It seems the stump has decomposed more and exposed all the roots of the cedar. The cedar now is about 25’ tall and is really sad. It has began to brown out and defoliate. This stump was about 2’ high from ground level.
If your stump is above ground level maybe hollow it out deeper than I did. 
Fill the hole with compost and too much fertilizer, keep it watered, cover it with plastic or a bucket, and it will be gone by next year.
What others are pointing out is true; it will sink the area so you should not plant anything you want to stay there.
Sounds like a worthwhile idea to try. Keeping moist soil on top will accelerate the decay of the stump.
I imagine you will dump soil on top to completely cover up the stump so it looks like a circular raised bed. Add mulch on top to prevent erosion. You could grow sunflowers on it, as they would have massive roots at end of season that should penetrate into decaying stump.
Cut a mulberry off 2" above ground level once. Then i hauled dirt and piled it on top 6"deep. It took 5 or 6 years but as mentioned that 3 foot diameter stump was totally gone. It was the largest mulberry i ever saw. It did cave in at that spot i had to bring in more dirt.
What does the bulk of the work is the fertilizer. It feeds the bacteria that goes to town breaking down the wood.
Personally I have a bag of pure potassium nitrate for special occasions such as this but any run of the mill fertilizer will have enough nitrogen to make the bacteria happy.
Good point, I’m honestly not sure. A couple of them were probably Douglas firs, not sure about the others. They range in diameter from just over 1 ft to just under 3 ft, here they are, maybe someone can guess an ID?
I’m no PNW tree expert, but I do my best to orient myself when I visit there. I have a brother who lives in Seattle. I’d guess the first photo is Bigleaf Maple. The others look like Doug Fir. The maple will break down very quickly. It’s already showing spalting.
Lots of things like to grow in rotten stumps and nurse logs. They are prone to having their roots exposed as the wood decays. The rotten wood is an excellent growth medium though. Not sure how much effort you want to put into it, but you could cut off near ground level and treat the center with high nitrogen fertilizer, creating a sort of ‘container’ near grade.
I think it depends on what trees they were. Oak stays in the ground for at least 15 years - know that by experience. I covered oak stump with soil in 2007 and made flower bed on top, planting between roots and on raised bed on top. Even covered with soil it still was there last year, when we sold the house.
Thanks for sharing that. Just speculating…I could imagine the primary recycler of some type of trees may be fungal and perhaps adding soil on top impedes the fungal activity for fungus that may specifically target the break down that type of tree.
Well timed post.
Now that it’s less hidden behind my old rotted fence. I want to complete the decomposition in some aesthetic way,
Blueberries or any Ericacae would be a good bet on the Doug fir stumps I’d think @swincher
Decaying conifers are good hosts and associates of Ericad mycorrhiza. You might have to work a bit at getting the fir to break down. The maple will be mush in a few years no matter what you do.
I’m telling you guys, put down way too much fertilizer and it will rot the stump in record time. The working ingredient is the nitrogen and as a matter of fact commercial tree stump chemicals are just that, overprice brand name nitrogen. The shovelful of compost just adds a healthy blend of decomposers while covering it maintains the needed humidity.
I had a stump for several years that I finally fertilized, it crumbled by the next spring.
I knew someone that used to swear by collecting and dumping urine onto the stumps to relatively quickly break them down. Or even easier, just pee on it when the neighbors aren’t looking.
Pretty sure that’s doug fir, judging by the deeply-furrowed bark. The most common plant I see growing on those stumps in 2nd growth forests is evergreen huckleberry (Vaccinium ovatum). The biggest caveat with V. ovatum is that most cultivars can’t handle more than about half day sun. Blueberry would probably work, but evergreen huckleberry has a much more aggressive root system and is drought-tolerant.
Same thing, nitrogen. 5:1 diluted urine has about four times as much nitrogen as a mix of Miracle Gro.
Red Huckleberry too. In fact, I think growing out of a decaying stump may be the only way I’ve seen the several I’ve encountered situated.
