There's a 6ft tree at the back of the garden (cordyline, i think) that has taken a bit of a battering from the recent winds and is now leaning over by about 15 degrees from upright. How can I fix it? Do I need to drive some kind of stake into the ground behind it and tie the tree to it? I notice it's a bit loose and wobbly at the base, so should I add some extra soil around the base. any suggestions would be welcomed