Answer: Unfortunately, based on your description I am not certain what has happened. It might a problem with the roots in that it did not root fully into the surrounding soil and thus suffered during the recent dry spell, or it might be a pest or disease problem. I would suggest you work with your county extension to obtain a specific diagnosis for the browning and then knowing that, work from there. If it is something that requires a chemical control they will have the most up to date recommendations on what to use and how/when to apply it. I hope it can be saved.
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