Sheet Mulching over Salal Roots

Hey there everyone!
I am trying to guild a cherry tree but first I had to remove a lot of salal, huckleberry etc plants and roots so I could even find the soil to amend it.  What am I facing if I sheet mulch over where a typical PNW understory once grew?  I tilled the soil with a broadfork and planned to sheet mulch at least 8 inches deep.  But, I pulled some roots that had traveled under a nearby log so I fear it will just creep right back in.  I plan to clear a few feet of it more past where I will plant my weed suppressing bulbs on the outer ring so that should help and I will bury a few inches of small rocks on the outer edge of the bulbs.  Do I stand a chance?  I found remnants of old landscaping as I was clearing so I know someone before me already lost the battle and I don't want to have the same fate.  I love the native plants and am keeping a lot of it on our property for food/medicine/goat browse/wildlife habitat but I need to control where it grows to some extent or it will take over.    Any advice would be much appreciated =)

Hmmm, I haven't tried to eliminate my red huckleberry or salal, but both plants really seem to like really woody, acidic soil. It could be that if you add a bunch of calcium and nitrogen to the soil, you'll change the soil enough that they won't survive. I know I nearly killed my evergreen (blue) huckleberries by adding too much nitrogen, and it was an amount that most plants are fine with. So, I'd think that if you chopped and dropped all the salal and huckleberries, added some wood ash or calcium, and did a nitrogen-rich mulch like partially (or not at all) composted manure or chicken bedding, you should be able to keep them from coming back, or at least coming back at an unmanageable rate. If you go with the non-composted manure, know that not much will be able to grow there for a few months. If you go with the partially composted manure, you should be able to plant a cover crop to keep the soil occupied until you're ready to garden.

By adding nitrogen and alkalinity to the soil, your soil will also hopefully be more receptive to a lot of typical annual garden plants that like soil more alkaline than ours normally is. I say "hopefully" because I am by no means an expert in soil science and am still trying to make my acidic, native soil love me enough to grow garden plants.

I just noticed that you said you were trying to grow a cherry tree there. Hmmm, the fact that your soil is happily sprouting huckleberries and salal probably means that you've got a LOT of woody material there, and perhaps a lot of cedar there, too (that's where mine loves to grow). You might find that, like me, not much likes growing there right away, and you're cherry tree might not be very happy. You might want to try making it more alkaline and nitrogen rich with your sheet mulch, wait 4-6 months and then test the soil. Then amend it. Then plant your tree. You're problem might not be so much the plants that are there, but the soil conditions that are making those plants so happy (because I really only have seen those plants taking over in really acidic, woody areas). Once you change those soil conditions, the salal and huckleberry probably won't come back with much vigor, or at all, and your cherry tree should be happy.

You have been well observant. After over 70 years of observation just south of you here is what I expect to happen and possible responses.

Though introduced into new areas by bird droppings salal reproduces principally by roots.  The remnants of roots will grow in the mulch and will be easier to pull than initially if desired.  Depending on your tree spacing and size also frequency with which you visit the area [zone] they can just be mowed.  There are some local land holders that maintain their road sides by mowing it with a riding lawnmower each fall. The cop and drop effect increases the root density and the new growth leaves are the favorite of the deer which reduces the pressure on the trees. Deer protection for trees interview.
As an under story Salal and our evergreen huckleberry with a dense over story keep themselves spaced out where with minor pruning you can walk between them. On a sunny edge they will be a dense hedge.
CONCLUSION Selecting your management according to your desired outcome salal and huckleberry can be a solution instead of a problem  

You did not mention the Hymalayan blackberry It also spreads to new areas by bird droppings but profligates by rooting the tips of the vines. Therefore must be controlled by trimming the vine tips back starting this time of year and all winter. Mature crowns will have a large bulb underground and are almost impossible to suppress but the bulb can be removed with the broad fork.  Selected crowns can be managed for an effective crop.  Some of the ones I manage have vines 2 inches in diameter and people buy them through the co-op or I charge them $5 to come and pick them. Where well trained I can pick a 3 gallon bucket in a half hour.

I have an area that I want to develop that got overgrown so if you wnt to come down and have a broad forking party in exchange for some trees You are welcome to come down It is about 1 1/2 hour drive.

off topic, but in my area of PNW, salal is infested with ticks.  In spring salal is teeming with ticks, but I have been bitten even in December.  Be extra careful tending salal.

Nicole Alderman wrote:
I just noticed that you said you were trying to grow a cherry tree there. Hmmm, the fact that your soil is happily sprouting huckleberries and salal probably means that you've got a LOT of woody material there, and perhaps a lot of cedar there, too (that's where mine loves to grow). You might find that, like me, not much likes growing there right away, and you're cherry tree might not be very happy.

I have had no problem with cherry and apple trees transplanted on the edge with salal and both red and evergreen huckleberry. The seeds which are a cross between the domestic and wild choke cherries sprout and grow right out of the salal. The red huckleberry will not survive as seedling unless it is growing in rotten wood  When they get 6 feet tall and diameter there root system can find enough water during the dry summer but my favorite one found the septic tank. They are a good candidate for anchoring a hugle bed.

Because you are looking for a cherry guild and can use the browse, you may already have the natural guild in place. At least it works for the ones along my driveway as long as  I can keep the Himalaya blackberries out. I dont have the goats anymore but the hedge trimmer works good.

Not sure what you're trying to guild around the cherry - but I second the idea that you might already have a workable "guild" of PNW natives.
If it's just about filling the space with happy, edible, mutually-supportive plants, I'd encourage you to do a survey (use Gaia's Garden or a similar regionally-specific plant book), and discover just how many functions are already thriving there.

If you want to grow something very different from the PNW typical understory, like alkali-loving brassicas or something, you are probably looking at clearing a bed, or creating a raised bed, to modify the existing soils.
(Bear in mind that part of what creates the acidic soil is the cool, rainy conditions - these promote a LOT of organic matter, and rinse away soluble alkaline salts.  So if you want to grow Middle Eastern or European annuals, which evolved in less rain and chalkier soils, you will have a lot of work to do to modify and maintain a non-local soil profile.  I generally have not done this on forest understory - I prefer to garden in already-disturbed soil, since it generally benefits more from the caretaker's attention.)

I no longer live in the part of the PNW where salal grows to problematic excess. I miss it.  I really miss huckleberries.  Swap you some cheatgrass and thistles, anytime.

I would definitely think twice about whether you can live with the salal, since disturbed ground often goes to Himalayan blackberries, thistle, and inedible invasives.
I'd much rather have the native berries.
Salal berries are edible but bland, ripe ones have a hint of nutmeg about them.  Red hucks are edible but tart.  Put them together, and you have some serious blueberry pie material.  Black coastal (evergreen) hucks work in this mix too.
Salal is also popular with florists as decorative greenery.  Used to be a market for it, Ernie remembers being paid for "brush-picking" as a kid.  One of the 'forest products' you can harvest without felling trees.

My recollection of the gardens I helped tend as a kid, and as a renter in Portland, is that salal is an easy keeper (doesn't need coddling) in woody soils, but it doesn't aggressively invade lawns or cleared areas.
Once you have eliminated the running roots from the area you're trying to cultivate, it takes time for it to re-grow from the edges.
The most common landscape strategies use salal in large planting beds with clearly marked, smooth boundaries.  Paths, mowed lawns, or other barriers separate native plantings (salal, iris, cedar etc) from introduced ornamentals or food plots.
I don't think some little introduced bulbs are going to have much effect on it, nor would I expect mulching to deter these well-adapted local plants.

I think of sheet mulching as most effective at surpressing mineral soil pioneer "weeds," by favoring woodland perennials over open-ground weedy invaders.
I would not expect mulch to work well as a strategy against forest understory rhizomes or root-creeping plants, they love those conditions.
I have heard of battling rhizominous plants (like invasive Himalayan blackberry) using mulch as the sort of decorative touch to cover up a truly sadistic strategy (corn gluten and molasses to hot-ferment compost all living residues, under a layer of light-excluding cardboard or black plastic, mulch or bark chip on top mostly for looks).

My version of Pacific Northwest permaculture would definitely include salal and huckleberries as parts of a guild.  
And probably some mushrooms, herbs, and edible flowers like wild ginger, violets, edible lilies if there's enough light.

Thank you all so much for the awesome advice/information.  Sorry so slow to reply.  After reading thru what everyone said and re-evaluating what I did and plan to do I am definitely going to make some changes.  Any orchard trees planted along the edge of where we cleared will be guilded with natives that are already basically there.  In fact I will probably do that with the entire perimeter of the orchard since natives are already established and I want hedges for wildlife and foraging.  I think it could work - then I will just amend the soil in the central region of the orchard and there I will plant by non-native understory plants etc.  There will be easier access in the center for soil and plant maintenance anyway.

Before I planted the cherry tree I did amend the soil before sheet mulching a giant donut around it.  UGh I hope I didn't go too deep and kill it.  See pic if you want a laugh =)  I hadn't even thought about the idea that since I changed the pH of the soil the native roots my not be so excited about coming back there.  Interesting thought...  I did put a ring of daffodils at the drip line and dug out so many friggin' rocks that I planned to bury a rock ring just outside the bulb ring.    After pulling all those roots and cleaning it up I started kicking myself thinking I could have just let that be the understory but it is just so close to invading our zone 1 that it was best.  Too, I will probably plant some herbs and maybe even veggies under it.  I don't really have an ideal location for an herb spiral in zone 1 so I was planning to spread my herbs out at the edges of that zone which is where the cherry tree sits.  Beyond the cherry tree will be the main orchard.

I certainly see the value in the local flora for us and wildlife.  It is just that we have a TON of it and I do need a little room for some fruit and nut trees and other non-native shrubs.  I am leaving the NE corner of our property almost completely untouched as our zone 5.  Loads of salal, huckleberry etc in that area... hoping to get some inoculated mushroom logs going too.  Seems to be the perfect spot!  

I am curious about the sadistic strategy mentioned by Hans.  I have a 5 gal bucket of molasses I have been trying to donate to various goat and horse rescues with no luck.  I had the idea to spread it in the garden/sheet mulch as I was building my beds.  Am I going to annihilate everything?  or is it only the combination of molasses with the corn gluten that does that?  I thought it would be a nice food boost to the composting army but maybe not so.... yikes!  Glad you mentioned that!

And thank you Peter for the tick advice.  I already have/had Lyme disease and I don't need anymore tick bites.  ARGH!
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Wish I could come down for a broad forking party but I am stretched so thin right now it took me 3 weeks to reply!  If things settle down here though I think that would be fun =)  I would have to bring my girls... oldest would do well but my youngest is a little pistol.  I could drive down and it could end up being a total disaster.  ahh well,... the life I chose  ....

thanks so much everyone!