Answer: Your shrubs need soil that is evenly moist yet well drained. That means it should be damp like a wrung out sponge, not sopping wet and not dried out. To know if you need to water, dig into the soil with your finger. If it is damp, do not water yet. When you water, apply it slowly and thoroughly to the soil, not to the foliage. The goal is to moisten the soil down to the deeper roots. Keep in mind also when you water that the roots spread out as they grow so they will not be concentrated at the base of the trunk.
It is better to give a deep watering less often than a frequent light soaking. After watering, wait a few hours and then dig down to see how far the water really soaked in; sometimes it can be surprising.
Using an organic mulch in a layer about three inches deep over the entire root area will help keep the soil more evenly moist, and it will help feed the soil slowly over time as it breaks down.
Yellowing can be a sign of overwatering, underwatering, overfertilizing, or even root problems where plants are not rooting out into the surrounding soil as they should. If you are still concerned about them, you might want to consult with your local county extension to try to get a more specific diagnosis of the problem.
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