We live in South West France. normally we get temperatures of up to 34 degrees C in summer, and short periods of minus 9 to 12 degrees C in winter.
We have had a patio consturcted and have left a one metre diameter hole for a tree to be planted to give some shade. The patio is laid on one foot of reinforced concrete, and underneath that there is solid clay, which in the hole makes water very slow draining. We have been advised that the tree roots may rise and distort the patio in time. Is this likely to happen? If so, what type of shrub or small tree would thrive in these conditions without endangering the patio?
We would be most grateful for any suggestions.