Location #2

S and S-W facing narrow strip of leveled land of 2 to 4' deep currently occupied by few azaleas, Buddleias and Hibiscus syriacus volunteers from the neighbor's garden, some daylilies, phloxes and weeds, weeds and weeds again. Behind this 'bed', but about 2-3' lower, there is another 3 to 5' deep tier of slightly sloping toward the back rocky undeveloped 'planting space' where zillions of Dicentra spectabilis and two zillions of wild raspberries (extremely sweet and tasty!) are growing together. And there is a third tier below the second one where 3 zillions of raspberries live very happily together with ... 5 zillions of Fallopia japonica.
And background to all of this is the gorgeous forest of 80-100' tall Liriodendron tulipifera (Tulip tree) whose seedlings of different type of maturity (from 3' to 10' tall) could be found in abundance on all three levels.
I think you got the picture :-((

Here is my question:
Does it make any sence to start the neverending war with all those wild things by try to eliminate all/most of them before planning and planting anything or simply clear some areas on Tier #2-3 on a one-by-one basis and plant some large and relatively fast growing shrubs that could compete with such weeds?
Namely, I have in mind different Viburnums, Physocarpus, Kerria, Sambucus, Heptacodium micoinoides, H. paniculata and quersifolia, Styrax, Callicarpa, Weigelas, Cotinus coggygria etc.

My thought would be to plan to clear everything off levels 2 & 3 first. I'd probably use a machine (brush mower or bladed weed whacker) to cut everything to the ground, cover with thick layers of carboard or multiple layers of newspaper and deep woodchips or other mulch. Then watch carefully and hand pull or use roundup on whatever comes through. In my experience, this won't be much, though you may want to paint stumps with brush killer before mulching. Plan now and replant either this fall or next spring. I wouldn't try to plant while all this mess is still around because even if the viburnums etc survive, it will always look terribly untidy.

If some of the plants on level one are worth keeping, I'd hand weed using clippers and a trowel to cut woodies slighly below ground level and remove herbaceous vegetation and then newpaper and mulch that area as well. Since it sounds like there is a good seed bank of weeds, I'd plant to use corn gluten and remulch annually for a couple of years, especially around new plantings.

A good rototilling will dig up most of the weeds.

Also,a great organic treatment for stubborn weeds is a blow torch. Honestly, burning them to the ground will snuff them out most times if pulling is not feasible.

I agree that clearing/cleaning and planning should be done first as nhbabs suggested; this will give him a clean plate and the ability to pull up any volunteers or small tree seedlings while he researches all of your excellent choices for buffer plants.These will that make a strong statement against a forest backdrop. Your son is so lucky to not only have space to work with but also to have your guidance.

Molie