The panama hat plant displays a harmonious connection with the Center facing direction due to its evenly spread foliage representing balance and stability. This bodes well with the essence of stability that rules the Center in Feng Shui principle. However, nuanced interpretations may vary depending on individual circumstances.

The gooseneck loosestrife aligns favorably with North-facing positions. This is said to derive from its upward growth, resonating with the symbolisms of North such as growth and ambition. Yet, it's important to note that Feng Shui interpretation is subjective, ensuring varied perspectives on its compatibility.

The old man cactus subtly exudes strength and longevity, a likely ally for a balanced Qi. Placed in the Northeast of one's environment, old man cactus might amplify Earth energy, the dominant element in this direction. However, its impact remains interpretable. Importance lies in the harmony and unique connection you feel with old man cactus.

In terms of Feng Shui, the mexican hens plant aligns harmoniously with a West-facing direction. This is because the direction signifies metal element, which complements this succulent's tenacity and ability to thrive in tough conditions, symbolizing Metal's characteristics. This, however, should be considered a general guideline rather than an absolute rule, as Feng Shui interpretations can greatly vary due to different perspectives and contexts.

The common lungwort possesses a vibrant, harmonious energy, suggestive of balanced Chi flow. It is ideally compatible with North facing orientations, due to its nurturing and growth promoting attributes which align with the Water element related to North, according to Feng Shui principles.

False buck's beard is considered a harmonious plant in Feng Shui, known for creating a positive energy flow. Its lush foliage and delicate blossoms promote a sense of tranquility and balance. When facing North, false buck's beard is believed to enhance career luck and networking opportunities, perfect for those seeking professional growth and success in their workspace.

Onions (Allium cepa), or onion, might exhibit intriguing influences when in alignment with Feng Shui principles. Their vigorous growth could be harmonizing with the robust and independent energy of the Northwest direction. However, caution is advised since their potent odor might contradict the serene ambiance we associate with Feng Shui.

The downy oak bears a semblance to the steady yet adaptable energy of the Earth element in Feng Shui. Naturally harmonising with an East-facing orientation, the plant could be seen accentuating health due to the association of East with family and health. Please interpret with thoughtful discretion considering variables in your environment.