The royal Lily harmonizes extremely well with the Southwest-facing direction in a space as per Feng Shui principles. The plant reverberates with Yang (positive) energy, a force complemented by the Southwest, symbolizing the earth element. However, interpretations may differ, grounding the subjectivity of Feng Shui.

The pacific Reedgrass harmonizes well with the Southwest-facing direction. This is reflective of its distinctive ability to harness the Yin energy typically associated with the Earth element of this direction. However, based on the holistic viewpoint of Feng Shui, one's personal experience and intuition may influence the actual impact of this guidance.

White indigo berry aligns harmoniously with Eastern Feng Shui, representing the element of Wood. This direction fosters growth and perpetuates the plant's inherent blooming characteristics. It's important to consider this is a commonly accepted belief, and its potency may differ based on individual interpretation.

The red ruellia exhibits an impressive compatibility with a south-facing environment in Feng Shui principles. This direction typically represents fame and success, resonating well with the vibrant red colors of the flower. The ambiguity remains, though, as ultimately, the plant's placement is subjective and dependent on individual interpretation of Feng Shui aesthetics and guidelines.

The winkleri harmonizes well in a Northeast-facing direction. In Feng Shui, the Northeast represents knowledge and personal growth. The succulent nature of winkleri symbolizes the ability to retain wisdom, thus enhancing this direction's energy. The opinion, however, might vary as Feng Shui interpretations are highly personalized.

The sofinampory displays elements of endurance, strength and upward movement, well-aligned with Metal element principles. Therefore, this resilient plant brings a dynamic and forward-moving energy, potentially enhancing the Qi of a space. However, its compatibility with the North-facing direction, related to Water element in Feng Shui, can be considered ambiguous. Some Feng Shui experts suggest plants can harness and focus their growth energy to aid the cooling characteristics of the North, creating a harmonious balance.

The giant wakerobin subtly complements the earthy energy of Southwest-facing locations, creating a harmonious balance. This compatibility is due to the plant's robust nature, echoing the resolute characteristics of this particular direction. Although firmly anchored in Feng Shui principles, interpretations may vary, cultivating a richer understanding.

Desert Saltgrass coexists harmoniously with the Feng Shui principles largely due to its resilient nature and ability to thrive despite harsh conditions. Suited aptly for the Northern aspect, its strength and endurance symbolize the water element of North - often associated with personal growth and self-cultivation. Remember, as with all things in Feng Shui, achieving balance is key.