1-There are a variety of things that could be planted in that narrow bed. Some good choices include annuals that could be rotated out in progressive plantings throughout the year. It really depends on how much sun that area gets as to which shrubs or perennials would work best there. If you would submit another question with more details about the sun exposures we can try to be more specific.
2-Ants come in many species and each is controlled best in a specific way. There are bait products that attract some species but not others. These are fairly safe to use. There are also various insecticide sprays that can control ants but may require periodic retreatment. If you can let us know the type of ants you are dealing with (e.g. sugar ants, carpenter ants, fire ants, harvester ants, etc.) we can provide the best options to help you control them.
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