Cherry laurel with dark spots on chlorotic leaf

Cherry laurel  with dark spots on chlorotic leaf

Observation - Cherry laurel with dark spots on chlorotic leaf. Description: The plant is Prunus laurocerasus , the Cherry Laurel. I beleive the plant is generally unthrifty because of lime or magnesium deficiency caused by its intolerance to the alkaline soil it is growing on. What I dont understand are the dark green spots

The plant is Prunus laurocerasus , the Cherry Laurel. I beleive the plant is generally unthrifty because of lime or magnesium deficiency caused by its intolerance to the alkaline soil it is growing on. What I dont understand are the dark green spots near the base of the leaf. I have seen this on other plants of this species in other gardens and at all times of the year. The spots are usually near the base of the leaf and towards the central rib.