I have clay soil in the northern suburbs of Melbourne.

I have a garden bed 600mm by about 40m along a picket fence on a corner block.

This weekend I have dug down about 400mm with a mattock and added 2-3kg of Gypsum (Brunnings brand from bunnings) every 1m2. Some of the really large clods of clay i removed to be thrown away. The rest i metal raked to break up the clods and threw the 3kg per m2 in stages during the mattocking and metal raking. Should have hired a rotary hoe.

I will be putting in either silver birches or the Bradford ornamental pear maybe Robina Frisias.

I am concerned about Wet Feet killing these trees. Before planting them, whilst I intend in addition to above ground preparation to mound them up about 10-20cm above current grass/garden bed level. I also want to add some additional soil improver to the clay parent&gypsum.

The obvious addition would be an organic type product like mushroom compost or Garden Blend ( 70% screened soil, 20% Compost, 10% Chicken manure) in a 50/50 or 80/20 mix with the existing parent soil.

http://www.baag.com.au/yard_products.html

Many gardening forums recommended this.

These people

http://www.hellohello.com.au/wetfeet/wetfeet.html

Have seem to researched it well and write

"PREVENTION OF WET FEET

Don't ever use 3 way, 4 way or organic soil mixes that contain a mixture of fine sand and animal manures. You can get wet feet even if your garden beds are well drained using these products"

Within a few weeks these soils become waterlogged and the organic matter decomposes causing the soil to compact into a very heavy wet anaerobic soil.

The soil additive should not contain animal manure or fast decomposing organic matter,

So based on this are most of the soils on the

http://www.baag.com.au/yard_products.html

site not good for wet feet prevention? whether the organic compost or the premium soil mix (this is one of those 3ways!?)

Shoud i be buying the bags of

http://www.hellohello.com.au/devotion/clay.html

and using one @$12.50 per tree plant. ( I will be planting about 15 trees)

Devotion Planting Mix for Wet Feet, Heavy & Clay Soils contains mineral gypsum to help break down the clay, coarse propagation sand to aerate the soil and to improve drainage and composted pine bark to add slow decomposing organic matter to your soil

I was told at the bulleen nursery specifically not to use pine bark.

So my questions?

1. Have I preapred the heavy soil correctly so far?

2. Is mounding the trees worth it and is 15cm too high?

3. What is the correct soil additive (not talking mulch) to go into the garden bed and hole with the new trees? Can you recommend a product ie. name, components and maybe even Melbourne retailer?

4. 50/50 or 80/20 parent/additive mix? with the above

5. what mulch product - name,components,retailer should i then throw over all of this?