The pincushion flower plant is harmonious for a North-facing environment. This is due to its tranquil color, suggesting water energy perceived in Feng Shui, which is complementary to the North's element, water. However, its compatibility can be different based on individual perception and interpretation of this ancient practice of energy balance.

The flower-of-an-hour is considered to carry soothing, harmonious energies in Feng Shui practice. A South-facing placement of flower-of-an-hour amplifies the flow of positive chi, associated with the Fire element, which is symbolically linked to the vibrant, fiery transitions in flower-of-an-hour's blooming period. However, the leaf-shape may suggest water elements, establishing a dynamic balance. Remember that Feng Shui interpretations can vary, and personal experience is key.

The panicledleaf ticktrefoil may resonate favorably with Feng Shui-practiced spaces. Its delicate structure is indicative of harmonious chi flow, which is crucial in Feng Shui. Facing Southwest, the panicledleaf ticktrefoil could potentially encourage marital happiness and romance, owing to the Southwest's association with the Earth element and the aspect of love in Feng Shui. However, individual experiences may vary as Feng Shui is a highly personal and subjective practice.

The selaginella tamariscina has a distinct and flexible form, matching the heart of Feng Shui equilibrium. Particularly compatible with the Center facing direction, the plant represents stability and adaptability, mirroring the core principle of the Earth elements which governs the Center of the Bagua. However, diverse views exist shaping the subjective nature of Feng Shui. Always consider personal context and belief when implementing these guidelines.

The tall flatsedge shows potential compatibility with Feng Shui principles. It's thought, without complete certainty, to harmoniously interact with the North-facing direction. This is due to its upright growth habit, symbolizing growth and advancement, akin to the Water element associated with North. However, this remains a subjective interpretation and may vary among experts.

The bitter ginger is believed to have a harmonious relationship with the North-facing direction. This plant's vigorous growth symbolizes a steady flow of prosperity, which aligns well with the Feng Shui water element associated with North. However, interpretations can vary, depending on the individual's understanding of Feng Shui principles.

The sea campion is said to align well with the North facing direction in Feng Shui, often associated with water due to its affiliations with marine environments. Please note, however, that Feng Shui interpretations can be contingent on individual circumstance and preferences.

Bentham's cornel seems to harmonize remarkably well when positioned facing Southwest. This might be due to its profound connection with the Earth element which is fundamentally associated with the Southwest direction. However, the subjective nature of Feng Shui implies that the results may differ according to individual perspectives and spaces.