The answer to 'why is my flower bed dead trees' is that there are several common causes for dead trees in a flower bed, including improper planting, disease, pests, or environmental stress. Symptoms may include wilting, discolored leaves, or the tree failing to thrive. To fix the issue, you'll need to first identify the underlying cause and then take the appropriate remedial action, which could involve transplanting, treating pests or disease, or adjusting soil conditions.
If the problem is more complex or you're unsure of the cause, it's best to consult a professional landscaper or arborist who can diagnose the issue and recommend the best solution. They can also advise on whether the trees can be saved or if they need to be removed and replaced.