Not to get too technical, but I'd guess by roots, your're actually talking about them regrowing from the rhizomes, and in general I doubt just the "real" roots which come out of those below ground rhizomes, can regrow them, if the rhizomes are removed. Being that those rhizomes should be relatively large and easy to spot and remove by hand you cuold perhaps get 100 percent of them removed, though the much smaller roots could easily break off and might regenerate, though I doubt it. Short of soaking the area constantly in some Roundup or other very strong weedkiller to constantly kill any regrowth til the roots and rhizomes can no longer fight back, they could be just dug up and removed, though obviously it could take considerable elbow greese to do the task. Using weed killer constantly of course could lead to a situation, where nothing else would grow in that area for a long long time and I doubt you want that!!

Andy I feel your pain I had scale on some indoor plants over and over. I use Ortho Malathion Plus Insect Spray Concentrate now and nnever saw scales again. Make sure you spry the soil also because the youn scale live there.

I see this is an old post but new people may have these same questions and this past fall i did the same thing that g6342856 did. I had a weedy area about 4000 sq feet on side of house that had agressive weeds and only a few small patches of healthy grass .So i first mowed to lowest possible setting then round up for a month like morpheuspa said. Then water the dirt each week to see any areas you missed then repeat round up again. After a months time either level the area or rototill .If area is level just rough up the existing top soil and sow the seed. Before you do this incorporate some starter fertilizer into the soil that prevents weeds and does not interfere with new seedlings. Then your good. I recently filmed a two month renovation i did in August and i used titan rx turf type tall fescue with good results and im now weed free you can see video below. It took some hard work but well worth the wait

id tell you to move ... but .. well .. lol.. that isnt going to happen ... the easiest way to get them up ... would be with the checkbook ... trust me on that ... lol i had to remove white whatever ... with a rake.. manure shovel.. garden sieve and mostly by hand.. it took me a month ... to do a 6 by 10 foot area ... just outside the front door ........ not to mention they couldnt be dug out .. because of landscape plastic underneath .. what a nightmare ... [i raked the loose rocks.. onto the flat shovel to put them in the sieve] but one thing comes to mind... you have a wooden house .. that needs to be painted every few years ... if this is just 3 feet or so ... consider leaving it to aid maintenance .. and build your beds further out ... remember.. i keep telling you.. on acreage.. space considerations change .... also keep in mind.. foundation plantings are meant to hide the foundation.. not be planted on them ... and again.. with your increased space ... consider leaving them there ... it will be the best money ever spent.. to hire a gang of brawny men.. with the appropriate skid steer... whatever.. to do the job.. and haul it all away ... if you cant just leave it there .... please dont get frustrated when i try to help.. i cant help doing project talk.. other than like a man .... just keep in mind.. my good intentions ... ken ps: have miss dig.. ID all your utilities.. and make photo records.. to insure you dont mess around with such.. near a foundation ... for me.. it was mostly silly stupid easy to know.. except the buried cables to the barn ... didnt expect them where they were .... and there was a rather unique placement of the gas line .. not really lined up to the meter .. well maybe it wasnt easy to know ... lol.. https://www.bing.com/images/search?q=garden+sieve&FORM=HDRSC2 https://www.bing.com/images/search?q=manure+shovel&FORM=HDRSC2 https://www.bing.com/images/search?q=skid+steer&FORM=HDRSC2