Posted: 27/09/2012 at 20:46
Hello - How brilliant to have a 'clean slate' - and in a year or two you will have a good-looking garden to be proud of (without the guilt/restrictions of removing/sticking with existing plants).
One thing I'd like to say is that the oak trees could well have a drying effect on your garden soil. I have one oak and in the 7 years here have been amazed at how the soil (clay also) a good 15ft outside the canopy appears to be sucked dry by the tree. It's worth bearing in mind. Fortunately I think 'your' trees are to the north, so at least you won't have the double whammy of summer shade. Also, the oaks attract squirrels - who seem to love nipping off the heads of tulips - so best not be too dependant on flowering bulbs!
The clay has most likely been horrible to deal with during hard-landscaping work, especially during this wet year - but it isn't a bad soil once it comes to plants.
Also on a more positive note... I have a jasmine (no idea of proper name) which covers a fence all the way up the garden and even under the oak. It forms a lovely green hedge and has some white flowers but it's the green screen effect I like. In a mild winter (hmmmm!) it keeps much of its green right through. For low ground cover and masses of bee-loved flowers I've found that Hardy Geraniums (not pelargoniums) are a great addition.
Good luck, and please post photos in next summer!