Colour changing plants

I have a small pocket of ground, underneath a bay tree, where whatever I plant in it turns pink.... So far I have had a white hydrangea turn pink (not entirely unexpected as they do do that depending on soil type), a white camellia turn pink and a white trillium turn pink. 

I can confirm that these were all white plants before I planted them there... most were moved from other parts of the garden where they had lived and flowered (with white blooms) for several years quite happily. The trillium had been happily sat with white flowers on it in a pot for several weeks before I had a chance to plant it, 2 weeks in the ground and it's now pink...😳

Any ideas?!