Common turmeric is commonly considered harmonious as per the norms of Feng Shui. While it doesn't fit universally, in the realm of nuances, it aligns well with the Southwest facing direction. This is largely due to common turmeric's inherent qualities that resonate vivaciously with the vigor and energy characteristic of the Southwest orientation, subtly signifying growth and abundance.

The sensitive plant often brings harmonious energy and interaction in Feng Shui. Its characteristics resonate well with the rejuvenating aspect of East facing directions. The plant's sensitive nature to touch symbolizes discernment and protection from adverse influences, fitting the East's Feng Shui concept of family, health, and renewal. However, every inhabitant's Qi pathway is different, and a comprehensive understanding of one's personal energy is essential.

According to Feng Shui principles, the warminster broom plant is believed to have a moderate affinity with the South-facing direction. This is possibly due to its vibrant yellow flowers symbolizing sun and summer associated with the South. However, the interpretation may vary as Feng Shui's application is highly subjective and technique-driven.

The yellow oxeye is largely compatible with South-facing premises due to its vibrant hues invoking the Fire element, believed to thrive in the South. Though, let this not be a strict guidewire as in Feng Shui, harmony is achieved variably, and depends on several intersecting factors.

The southern blue flag signifies peace and self-discovery, aligning well with the principles of Feng Shui. Placing it towards the North direction can stimulate personal growth and inner curiosity, as it resonates with the element of water, which is traditionally associated with North in Feng Shui. However, preferences can vary as the interpretations of Feng Shui are highly individual.

The scarlet flax exhibits an interesting harmony with the Southern direction. In Feng Shui, South-facing homes resonate with the element of fire, symbolizing warmth and illumination. The fiery scarlet bloom of the scarlet flax mirrors this element, potentially encouraging a flourishing energy essence. However, harmonic affinity varies significantly based on personal energy dynamics, thus necessitating individual interpretation.

The fragrant snowbell displays a significant harmony with the Southeast direction. This stems from Feng Shui principles, which associate this direction with the Wood element, perfectly aligning with the plant's characteristics. However, remember that the application of Feng Shui is personal and requires a delicate balance.

The purple nightshade harbors a mystic potential in Feng Shui, notably with a South-facing orientation. The vibrant hue of this plant, emblematic of the Fire element, harmonize well with the South; a direction symbolizing recognition and fame. However, one should exercise caution, as Feng Shui embraces the essence of balance and individual context.