The answer to 'garden yellowing' is that there are several common causes, including nutrient deficiencies, overwatering, disease, or pests. Symptoms may include leaves turning yellow, stunted growth, and overall poor plant health. Solutions can range from adjusting soil pH, applying fertilizer, or treating for pests or disease.
If the yellowing is widespread or persistent, it's best to consult a professional landscaper or horticulturist to diagnose the underlying issue and recommend the appropriate treatment. DIY solutions may work for minor cases, but a pro can provide expert guidance to get your garden thriving again.