Grumpy tackles readers’ questions about choosing the best clover for your lawn, troubleshoots common crepe myrtle problems, and spotlights the Plant of the Week: the Diamond Spire Gardenia.

Known as the “lilac of the South,” crepe myrtles can’t help but impress when they produce their colorful bounty of crepe paper-like flowers from spring through early fall. But if you’ve ever struggled ...