Backwards engineering hugulkultur project

Hello! Thank you for including me in your community! We have finally moved onto some land, and that land includes some wonkey hugulkutr beds. We are excited to say the least, but a little confused. Our beds are 3 years old, six feet high, and, according to concerned neighbors, primarily composed of 3-4' diameter downed cottonwood trunks. They are covered in invasive tansy and form a ring around an area approximately 5000sf, rough estimate, with a center area left flat. There are two living apple trees in the mix, couched on the NE of the enormous mounds, but they are currently buried under 4' of snow. I liberated their whiplike branches today. They are young, they will recover. But the mounds! They are so tall! 10' tall with the snow. Of course it will melt, but then we will have the tansy to deal with. North Idaho. Spring is going to get going in May. I'm thinking sheet mulch with cardboard or chicken straw or both, and planting a few things in holes here or there. The neighbors (their combined wisdom spans centuries) are in favor of razing the beds with a tractor and tilling, but I want to give it a go. I'm just wondering what to do--they are so tall. The north side... Of course up here the sun is very high during the growing season. I'm aware of the need for a greenhouse but that will not be ready in time, so I'd like to focus on a few perennials and a weed-elimination project this year, and maybe a cover crop if all goes well, in the fall. Do I have that right? This is my first large garden. We have poor soil which is sandy and well-washed, as we are by a river-wetlands. My main question is, Is Six Feet Too High? They are like little alpine spires in my flat riparian woodlands yard. Any advice or encouragement welcome. Will post updates as they are available--right now we are trying to afford a truck so we can get more organic matter in a compost bin. All we have right now is chicken manure and straw, and in the spring unlimited amounts of swamp grass and logging slash.

Welcome  to Permies!
Hugel mounds  always settle, so 3 feet high may get shorter.
My main concern would be about the steepness of said mounds.
If they are too steep,  the soil won't stay in place.
Adding cardboard might deflect rain away from the mounds,  but otherwise seems like a good idea.
Maybe burlap bags would suppress the tansy,  yet still allow water through and eventually biodegrade?
The swamp grass seems like a great biomass to have on hand.

First off, welcome to permies.

I would not raze it or till it. Seems like that would immediately & almost completely destroy three years of soil & soil life development. The first few years of a new hugel are the hardest, it's just now hitting it's stride. Consider what the most recent hundred years of collective "wisdom" has done to commercial farmlands across the globe. I'm not familiar with tanzy but a deep mulch & thick cover crops might help get it under control.

The minimum requirement for the permie PEP/PEX hugelkultur is seven feet. Some are even taller.   https://permies.com/wiki/98574/PEP-BB-gardening-sand-hugelkultur

I would certainly not raze the mounds. Is it possible that you can let the chickens loose on the mounds? That and/or heavy mulching like you layed out sound like a great path forward. At 3 years old those puppies are just hitting their stride, and it would be a shame to knock them down now

I looked up tansy, looks like it is medicinal, but hard to dose safely, not recommended. What IS cool though is it "acts as a natural insect repellent." "Tansy was a popular strewing herb in times past because it's clean, camphorous scent repelled flies and other pests.  It is still a good custom to plant tansy outside the kitchen door and around the garden for the same reasons." Oh neat!! I need more pest repellents.. wonder if it will grow here.

As far as the hugel, I'm with Mike Barkley

Seems like that would immediately & almost completely destroy three years of soil & soil life development.

:D

Update: We've mulched about 1/3 of the mounds. Grass is growing up through the mulch (we used unfinished chicken straw.) I took a mini-rake to some of the patches, and accidentally ripped up some mint. So good news, it isn't all tansy and grass. But I have no idea what to do about the grass. Tried to plant some onion sets but the soil is hard, so I got a spade and slid them in like I would tree saplings to reforest, and in the process I found several mouse holes. The bones of the mounds are just under the soil, branches and logs, so I couldn't do much except fill the holes with mud. I feel like if anything accidentally grows it will be instantly eaten by the village of mice living under there. Then I threw out some old seeds I didn't have room to start inside, mustard, kale, poppy, and radish. I'm hoping the rain knocks it down into the straw. Plan for the month is to cardboard the flat parts and figure out how and whether to till there, mulch the berries when the snow melts off, and to do alot of guessing and praying. The soil is much more clay than I had thought. Grass! Any thoughts? Thank you hugellers. In other news, none of the seeds we planted indoors have sprouted yet,  but it's only been five days so hopefully they will. I also made a cup of poplar bud oil for salve, which is only a quarter of what I meant to, but it turns out I was late to harvest poplar, and late tapping birch as well.

The hugel's at Wheaton Labs are 12' high.  Here's a thread showing them being built and what they've looked like through the years:  https://permies.com/t/giant-hugelkultur

They have a lot of grass on them now which they just chop and drop to mulch the other plants.

Thank you Mike those are some awesome hugels! They remind me of the cliffs behind my old home in Cali, which were sandstone, sand, monkeyflower, oak seedling, manzanita, and poison oak. We had chipmunks living under the roots of all the principle shrubs, it was very cute.

Here is my long overdue hugelupdate. The mice are actually some species of gophers, very intelligent and prolific. They eat 100% of the garlic and 95% of the girasole roots I plant so I moved those crops off the hugels. The one nice thing about the gophers is that bumblebees absolutely adore their tunnels and we have tons and tons of bumbles in the spring.

The tansy was not hard to remove, I don't know why because it is still terrorizing the rest of the yard, but after pulling it all it didn't really come back. Grass has remained the major problem. Grass with a thick thick matted sod network of roots that choke and exclude other plants. Cardboard caused a slug explosion and we are short on ducks so I swapped it out with straw, thicker and thicker applications, until I finally settled on 12" thick soaked rotted straw. The grass doesn't come up through that until the second year. Except yarrow, which grows through the straw eventually, I have to make little holes to plant anything. In areas where the straw has been down for a year, I can rip out the residual half-dead sod from under the rotted straw and make a little bed, sort of like a raised bed bordered in straw, that I fill in with compost and soil from elsewhere. I'm growing strawberries, garden sage, a couple of other herbs, and squash very successfully this way, but they all need lots of water, so maybe I'm not doing it right. The continuous gopher tunnels probably ruin a lot of the moisture. And we still don't have a trailer so I'm still not adding anything except chicken straw and compost.

Things growing themselves include: raspberries, black-cap raspberries, snowberry, wild roses, nettles, peppermint, speedwell, hollyhocks, thimbleberry, and pink spirea. The raspberries do so well that I'm ripping out a section and putting in improved berries this year. We have the wild-type and the berries are super tiny. I'm hoping the improved varieties do well, too.

The hugels do create a zone of moisture at their base where I have many perennial herbs planted that do not need a lot of water: lemon balm, hyssop, anise hyssop, catnip, iris, echinacea, lady's mantle, and columbines (not an herb though.) Another thing they do for the garden is to shelter the oval inset in the middle from the dust from the dirt road nearby, and they provide a little bit of privacy. I'm almost wishing the shorter hugel was a little higher now. And they give the garden panache, which is indispensible.

Upcoming plans, besides trying a new kind of raspberry, include putting some of the herbs in gopher cages, experimenting with CO poisoning, trying to rent a rat terrier, and replacing a few of the native shrubs and nettles with currants. I'm also watching for things that like drier conditions, and things gophers won't eat. Will try to post pictures this season.

Ok so sad news for one of the hugels, it is going to get moved in order to reno a carport. New tractor is in the works, need a new home for it! There are options for moving the hugel:

1. Take the top off and layer it, over another course of woody material, to raise the height of the shorter hugel, which is remaining. This will definitely happen, the question is how high.
2. Compost the remains in the compost bin, to be spread on the garden later, or
3. Use the remains to start a new hugel.

Hugels are great, at least I'm learning to love them. I'm just wondering what it is going to look like in there. Can't wait to check out all the gopher architecture, too.