Colby Codner

I am experimenting with something similar on my little acreage.  I've toyed with hugel mounds in spots, and just stacked dead tree and brush limbs in wind rows (parallel to fence) in others.  My objective for a hedge row include screen/barrier, food production, pollinator food/attractant.  What has worked best on my place (eastern Cleveland County) best so far has been the wind rows.  The sumac and wild blackberries have made a fairly effective barrier to any sort of casual human foot traffic.  I get loads of blackberries in the summer.  

I've also been trying to cultivate a trifoliate orange hedge, but it's been slow going.  You can go pick up some trifoliate oranges at the OSU at OKC campus from the south side of the greenhouses in their botanical garden.  Those little oranges have a SURPRISING amount of seeds in them, and your hands will get covered in a sticky resin if you deseed them.  I've grown them in some really sandy/clay in full sun and in shaded sand loam.  Obviously, the sandy loam cohort has done better.  

I've not tried a Bois D'Arc hedge yet.  But I am growing some black locust, and they've done amazingly well.  These were intended for firewood and bee forage.  I will coppace them when they get to firewood size, and let them grow back without thinning them out (to make a more impenetrable hedge).  I've been planting them about 3 or 4 feet apart.  Beware goats and saplings though.  Goats have a penchant for eating anything you plant, and amazingly somehow managed to kill a lot of my black locusts by constant grazing pressure.  

I have doing something similar as I've been clearing my little acreage.  I've just been creating fairly big piles of old blackberry canes, piles of greenbriar I've been yanking from trees, tree branches, trees I've cut down to clear my fence line...and crummy, non-native trees (pines in my locale).  I've also been clearing sumacs and adding them to the piles.  The piles have decreased in volume some, but I keep adding to them yearly.  So far, blackberry and elderberry have colonized the fringes, along with white germander, sumac and maypops.  I have been doing all of this by hand, but my extemporaneous "hugel" pile is several hundred feet long, and averages about 4-ft in height.   I have no plans for plantings on or near this, but I like that blackberry has colonized it.

Plants have no problem growing through asphalt.  But, they have to be able to receive water & light.  A continuous asphalt pavement surface can be relatively impervious to water.  It more or less has to be.  If it wasn't, water would compromise the subgrade, and weaken the surrounding pavement and cause potholes, etc.  As soon as there is an opening, plants will grow right through it.  

There is little excess asphalt left on pavement by the time it arrives onsite, assuming this is hot-mix.  If this is a chip seal road, then there is always excess screenings to mix with the applied cut-back asphalt.  I have only ever seen one project where a contractor screwed this up, and was working when they shouldn't have been.  Contractors won't apply an ounce more asphalt cement than they need to, because that will eat into their profit margin.

I assume the road is a public road?  If so, you don't have a lot of recourse on determining methods and materials for construction and maintenance.  Asphalt really isn't all that toxic in the form where you, or the general permies, are likely to interact with it.  It's fairly stable, and sometimes used to coat (encapsulate) otherwise toxic materials (mine chat for instance).  But, I can see where you might have an issue with channelized stormwater flow that could cause erosion.  Without seeing what your dealing with specifically (in terms of stormwater flows), a general recommendation is about all anybody could offer.  You could put in a stilling basin at the end of the pipe to reduce runoff velocities, but it would still need a flume of some sort to mitigate the runoff through your property, and not cuase a problem for your downstream neighbor.

I thought that I'd have something useful to add to this topic when I remembered that a significant portion of the commercial hazelnut crop is grown in Turkey.  The epicenter for hazelnut production in Turkey is Ordu (Lat 40.98, Long 37.88 ).  

I bought some little seedlings at Tractor supply earlier this in hopes that they would add to my hedgerow, but my locale is really, really hard on plants.  I'd even qualify the climate as adversarial.  The only things that do well here are invasive species elsewhere.