The steeplebush plant tends to flourish under well-lit conditions, aligning it harmoniously with north-facing arrangements, as this direction promotes clarity and insight according to Feng Shui principles. However, the strength of this compatibility may be subjective, shifting under differing perspectives.

The rough maidenhair fern plant embodies a steady growth and distinct tranquility, which complements the energy of the East direction. As per Feng Shui principles, the East represents dawn and renewal - a harmony that rough maidenhair fern resonates with, potentially influencing a positive flow of Qi in your space.

The engelmann daisy boasts a strong affinity to the South, likely due to its vibrant yellow blooms that symbolize 'fire' in Feng Shui, much like the Southern direction. This plant can encourage positive energy when placed in South-facing positions. However, perception and results might vary, reflecting the uniqueness of every individual's chi.

The rose cactus is generally seen as auspicious in Feng Shui due to its vibrant blooms symbolizing vitality and energy. This plant is notably compatible with the Southwest-facing direction, which represents relationships, love, and the feminine aspect in Feng Shui. Rose cactus's radiant energy can harmonize with this space, enhancing interpersonal dynamics and sparks of romance. However, its compatibility should also be evaluated based on personalized Feng Shui elements for finer adjustment.

The proso millet is an intriguing choice for Feng Shui applications. Its propensity for robust growth symbolizes determination and perseverance. Situated in the Northwest direction, it could foster the energies of helpful people and travel, as in Feng Shui, Northwest is connected to these aspects. Always remember, each placement resonates differently to individual users, diligence in personal observation is advised.

The chinese Boxthorn reflects harmonic energy compatibility when facing Southeast. The symbolic qualities of fruition and rebirth align with the Southeast's power of fostering wealth growth and career success. However, each individual's Chi interaction with plants is unique, inviting varied interpretations.

The Feng Shui compatibility of the snake plant is generally positive. As the plant is known for its air-purifying abilities, it can harmonize energy flow, particularly in East-facing sectors. This direction represents health and family in Feng Shui, making the plant conducive for enhancing the chi in these areas. However, remember that Feng Shui's application is profoundly personal and can vary in effectiveness.

The firecracker bush is an intriguing presence in Feng Shui. It is said to emit a formidable Yang energy, attracting positivity and vitality. In relation to South-facing locations, it could potentially enliven the space due to its fiery nature that aligns with the element of the South - fire. However, as each setting is unique, the results may vary and should be interpreted with discernment.