Question
When I moved into the house, there were 6 large swamp oaks in the yard that left lawn depleted of any ability for growth.  I encircled the area (about 700 sqft in shape of a boomerang)with foot and half of pure compost...planted perennials, bushes and small evergreens. Neighbors loved it, but I don't feel growth is very good.  
QUESTION:  How can I remedy the soil as I cannot turn the soil since all the plantings have settled in.  I have put mulch (3" in past).  When I dig in, the soil has white vein-like look scatter throughout.  I thought of putting layers of newspaper topped with dirt thru the winter (NE region, CT).  Is there anything I can put on top that will breakdown the layers of compost into the HARD, HARD clay beneath?  When I initially put in the plants, I dug past the compost layer, into the hard brick-like clay and amended the hole with good mixture of clay and compost. This garden is 4 yrs old now.  HELP!

ANSWER: Hi Grace, I would liked to have had some clay in your compost.  Clay particles are very small and are great for retaining nutrients and water.  Compost has very little nutritive value and allows most of the fertilizer you give your plants to move through with the water.  It's a great soil additive, but not very good for growing long term.
Try fertilizing with Osmocote fertilizer.  It is a timed released fertilizer that feeds micro doses of fertilizer over 90-120 days.  One application in the spring should be all you need if live in USDA zone 6 or northward. Zone 7 south apply a second application mid to late June.  You'll need 20-25 lbs per application.  I think you will see a significant improvement in growth.  Just broadcast it on the surface.
The white veins you see is a fungus.  It's growing in the decomposing organic matter and is not normally a problem (a few, like fairy ring, can be).  Mulching is fine, but when you feel the urge to mulch again, rake the decomposed mulch out and apply a coarse, fresh layer.  You don't want to add soil over the roots of existing shrubs and trees.  It doesn't take much to damage or kill them.  Jim

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QUESTION: Thanks for your answer.  I'm not sure if I conveyed accurately last time, but the clay soil underneath is very hard, compacted and dry. It is like cement as the surrounding swamp oaks suck up all the moisture.  I will put the Osmocote fertilizer in the spring, but is there anything I can do now before the snow comes to sort of season it like laying down newspaper then some soil????

Answer
Hi, Once again, you do not want to add soil on top of existing roots.  Creating a flower bed under the oaks where only a small percentage of the oak roots are covered will not harm the tree. Covering more than 20-30% of the rootzone with as little as 1" of soil can injure the trees.  Damage you will not see for 3-7 years until limbs begin to die in the canopy. The roots are at the surface for air, don't cover them.  Covering the area with a thin layer of newspaper and mulch will not hurt swamp oaks, but I would prefer to not use newspaper.  At some point you'll need to rake out the area and mulch again and the newspaper makes a mess.  I'd use landscape fabric under the mulch.  
If you don't want mulch in the areas around you flower beds, then consider a very dwarf groundcover.  Vinca minor or Lysimachia nummalaria make very good, low maintenance groundcovers.  Because they spread by running across the top of the ground, the soil quality is not important.  Spray feed them once a month during the growing season and they'll root into anything.  I've had them root into concrete.
The other option is to let it do what it would do naturally.  Let the leaves accumulate in unplanted areas.  It wants to be a forest and letting the area become one is much less work.  Jim