Bee balm is a plant that attracts pollinators and adds a splash of color to your garden, but it can also be prone to mildew and needs good air circulation. Therefore, it is important to choose companion plants that can hold their own against its aggressive nature and do not require very different care. Here are some plants to avoid planting with bee balm:

• Mint: Mint is an aggressive spreader that can crowd out bee balm and prevent it from getting the space it needs to grow healthily.
• Bamboo: Bamboo is also known to take over gardens if not controlled, so it should be avoided as well.
• Yarrow: Yarrow is similar to tansy in that it can become aggressive in the right conditions and wont get along with bee balm.
• Delphinium: Delphinium is prone to mildew and fungal rust, which are also common to bee balm, so it is best to avoid planting them together or give them plenty of room for air circulation.
• Phlox: Phlox is another plant that is prone to mildew and fungal rust, so it should be avoided as well.
• Sunflowers: Sunflowers grow tall and cast a lot of shade, which might not be the best neighbor for bee balm.
• Large shrubs: Large shrubs that grow tall and cast a lot of shade, like some types of large shrubs, might not be the best neighbors for bee balm.
• Plants that require moist soil: Bee balm prefers well-draining soil and full sun exposure, so plants that require moist soil might not be the best companions.
• Plants that require shade: Bee balm prefers full sun, so avoid planting shade-loving plants nearby, as their contrasting light requirements might create issues.

In general, it is best to avoid smaller and weaker plants that might be crowded out by bee balm. Another consideration is pests and diseases. Bee balm most commonly suffers from slug damage and downy mildew, so plants that also struggle with these problems should be planted elsewhere to prevent spread.