The showy Penstemon plant represents an intriguing element in Feng Shui practice due to its flamboyant character, which is in harmony with the vivacious energy of the Southwest direction. This connection is due to both the plant and this direction being associated with love and relationships, but remember, these interpretations can substantially vary.

Primarily, green and gold can effortlessly blend into any space, hence pleasing the Feng Shui energy flow. The blend of its colors naturally lean toward the Southwest direction - a direction synonymous with love and relationships in Feng Shui. Consequently, its presence may subtly promote harmonious energies in those areas. However, as Feng Shui theories vary in individual interpretation, adaptability remains pivotal.

In terms of Feng Shui compatibility, the purple mountain saxifrage presents an intriguing dynamic. Being an alpine intricacy, it embodies resilient energy, fortifying the Eastern-facing sector associated with Health and Family. Its purple hues are subtly powerful, augmenting wood energy while maintaining a harmonious course within the complex Feng Shui spectrum, thereby inviting vitality and cohesion. However, its compatibility remains layered, demanding personalized interpretation.

The maryland Golden Aster is harmonious with South-facing environments. This aligns with Feng Shui principles due to its vibrant, golden flowers, symbolizing 'Fire' element, which is dominant in the South. However, interpretation varies, thus personal perceptions and environment should also be taken into consideration.

The pyramidal saxifrage is thought to carry a subtle sway of Yin energy, promoting calmness and reflection, making it potentially beneficial when placed in a West-facing room or area. The West is linked to element Metal in Feng Shui which may harmonize with the plant's purported Yin traits. However, Feng Shui perceptions may vary according to individual practitioners.

The golden blue-eyed grass is widely considered compatible with the Southwest-facing direction, exuding positive energy. This is believed to derive from its radiant glow, which complements the soft earth elements associated with the Southwest in Feng Shui. Nonetheless, interpretation is highly subjective and compatibility can vary among practitioners.

The turkey oak embodies strength and resilience, often applied as a symbol of grounding and stability in Feng Shui. Despite assorted interpretations, it's generally seen as harmonious in the East-facing zones, due to East's association with family health, which aligns splendidly with the turkey oak's robust nature. Please keep in mind, individual experiences may vary.

According to the principles of Feng Shui, bigflower selfheal aligns harmoniously with a Southwest-facing setting. This is due to its perceived ability to bolster interpersonal relationships, an attribute associated with the Southwest in Feng Shui lore. As with all Feng Shui principles, this interpretation can vary.