You'll find that any leaves that don't receive at least some sunlight throughout the day will turn yellow and fall off. This is a preservation technique of the plant that ensures it's not sustaining leaves that are providing no benefit.

The leaves will start to yellow if they’re suffering from water and/or nutrient stress. You could also check the pH of the soil using a pH test kit, but unless the result shows your soil to be either strongly acidic or strongly alkaline, this is unlikely to be the problem.

There are three main causes of yellow leaves of evening primrose. If it is caused by insufficient light, it needs to be moved to a sunny place to supplement the light. If it is caused by insufficient nutrients, it is necessary to supplement nutrients in time. If it is in the growth period, liquid fertilizer can be applied 1-2 times a month.

If the lovely dark green leaves of your Murraya paniculata hedge are starting to turn yellow, there could be a few probable reasons. This could either be a problem with over or underwatering, a lack of nutrients, or that your climate is not suitable for these warmth-loving plants.