In Feng Shui, the bottle gourd excels in promoting essential harmony. Ideal for a Southwest facing direction, the bottle gourd resonates with the Earth element, intrinsically connected to this direction. A tantalising balance of Yin and Yang energies is fostered, enhancing overall stability and positivity within one's abode. Please note, interpretations vary and this description promotes a common, yet subjective viewpoint.

The wild service tree presents an intriguing compatibility with a Southwest positioning. Acknowledged for its robust structure, this tree aligns perfectly with the earth element commonly associated with the Southwest according to Feng Shui principles. The impact is anticipated to be largely positive, creating a harmonious and balanced environment, yet this can vary based upon individual circumstances.

The copper pinwheel can be a critical part of Feng Shui arrangement. The plant’s vibrant rosettes were mentioned to usher in auspicious chi, suggesting prosperity and positivity. However, positioning is essential for ensuring harmony. When faced southwards, the plant's radiant energy is thought to mirror the sun's fiery vitality, supposedly boosting fame and reputation per classical Feng Shui traditions. Please note, these concepts can vary greatly across different schools of thought.

The welsh onion is often perceived as harmonious in the Southwest-facing direction. This outlook subscribes to the timeless Feng Shui principle of 'Earth,' which governs the Southwest. The welsh onion's sturdy, upright growth subtly mirrors the robust, grounding energy of the Earth element, potentially contributing to a sense of stability and balance in the environment. As with all Feng Shui concepts, personal experience is paramount.

The moonflower exhibits a subtle harmonization with the West-facing directionality. It blossoms during the evening, symbolizing the setting sun developing in the West. This creates balanced Yin energies, echoing wisdom and tranquility per Feng Shui principles. However, personal experiences with moonflower may slightly differ, upholding the doctrine of individual vibrational resonance.

The euphorbia contributes subtly to balance when placed in a Southwest-facing direction. This may stem from its inherent earthly energy, which harmonizes well with the Earth element associated with this orientation. As a Feng Shui practice, this does not apply universally and should be reinforced through personal empathy with the plant's vibrancy. The nature of Feng Shui mirrors the concept of uniqueness - what works for one may not work for others.

The mexican creeping zinnia's smaller blooms and spreading habit perfectly harmonize with Feng Shui principles emphasizing balance and modesty. When concerning placement, the South-facing sector will particularly benefit as the mexican creeping zinnia embodies Fire due to its vibrant yellow flowers, a color associated with warmth and inspiration, befitting the South’s corresponding life aspect of fame and reputation. Still, as with all Feng Shui applications, the effect is inherently personal and may diverge depending on individual circumstances.

The blue throatwort is thought by some Feng Shui practitioners to thrive facing North, owing to its affinity with water element which is symbolically associated with North. This though isn't universally accepted. A careful balance must always be maintained; such is the subjective nature of Feng Shui.