The longleaf groundcherry is considered a harmonious plant in Feng Shui due to its balanced energy. It sports a unique compatibility with the Southwest direction, traditionally associated with earth's element, perhaps owing to longleaf groundcherry's adaptive nature of thriving in diverse soils. However, individual energies do play an important role, making this compatibility subjective.

The golden columbine plant exhibits a notable amicability in South facing directions. In Feng Shui, South represents the element of Fire and associated with growth and vitality, which relate to the radiant golden hues of the golden columbine. This alignment amplifies its ability to attract positive energy, but the exact impact may vary for individual settings.

Aesthetically pleasing with robust energy, the early goldenrod brings harmony when placed at the Center. It serves as a symbol of resilience, amplifying the area's balanced vibe. Subject to interpretation, these attributes contribute to Feng Shui compatibility in one way or another.

The spike lavender is subtly harmonious with the Southwest-facing direction. Enthused by the symbolic character of Feng Shui's Earth element, predominant in the Southwest, the spike lavender's uplifting and invigorating features evocatively balance the energy. Nevertheless, given Feng Shui's complexity, personal observation and adaptation remain paramount.

The broadleaf arrowhead is generally compatible with Feng Shui principles. Its broad leaves symbolize embracing vitality, which is beneficial in harmonizing energies. When facing North, the plant can strengthen the aspect of career development due to its Water element association in Feng Shui that aligns well with the North's representative element - Water. However, the compatibility may vary due to personal interaction and the plant's actual condition.

The blue Flax exudes a sense of tranquility and modesty, aligning well with the philosophy of Feng Shui. It is a fine fit for those seeking harmony and serenity in their space. As for its alignment with North, it's linked with the element of Water in Feng Shui, and blue Flax's calming attributes can be seen as a manifestation of Water's depth and perseverance, enriching the energy flow at a northerly direction. However, the interpretation remains subjective, varying according to the individual's unique energies and perspective.

The red-stemmed Feather-moss has an interesting compatibility with the North. With its widespread, dense cover it symbolizes protection and abundance, resonating with the Water element that is associated with this direction. However, it's important to harness its energy with discretion to achieve a pleasing, harmonious environment.

The black bat flower has a complex relation with Feng Shui due to its peculiar aesthetics, often associated with a strong, enigmatic energy. It is considered intriguingly compatible with a North facing direction. The plant's dark hue complements the element of water, dominant in the North, symbolizing depth, introspection, and mystery, alluding to an impressive harmony within the realm of the 'mysterious'. Remember, the universe's energies are dynamic, and interpretation can vary.