The little nipple cactus harmonizes well with Northeast-facing arrangements. It exudes a calming essence, ideal for promoting personal growth, typically associated with the Northeast's Earth element in Feng Shui. However, remember that Feng Shui is deeply personal and may individually vary.

The heliotrope infusing the surroundings with invigorating energy, brings positive change to the environment. Quite apt for the northeast direction; the traditional sector of Knowledge. The subtle mixing of energies may aid in imparting wisdom and enlightenment in a mysterious Feng Shui way. However, interpretations may vary, depending on personal perspective and circumstance.

The mother of hundreds plant, with its robust nature and rich symbolism, is compatible with Feng Shui practices due to its potential to stimulate positive energies. Especially when placed in the Southwest corner of your space, it could foster love, harmony, and relationship growth. However, interpretation may vary, and the ultimate Feng Shui compatibility depends on individual circumstances and preferences.

Possum grape is conventionally associated with fluidity and adaptability, traits echoing the Water element in Feng Shui. Perceived favorably for Southwest-facing areas, it resonates with the Earth element governing this direction, finely balancing its Water essence. However, this harmony may vary, for the ebb and flow of energies is an entirely subjective domain.

The hairy crabgrass aligns well with the principles of Feng Shui, particularly when it faces Southeast. This direction, related to wealth and prosperity in Feng Shui, seems to harmonize prolifically with the hairy crabgrass's natural endurance and growth vigor. Naturally, interactions of energies can be subjective, inviting various interpretations.

The apple-of-peru bears a harmonious resonance with the South, owing to its visually stimulating blue flowers that can create vibrant energy (known as 'Chi') in Feng Shui practices. However, given Feng Shui's highly individual and complex nature, interpretations may vary.

The giant ironweed holds a symbiotic connection with the Southern direction. This association stems from the plant's vibrant purple flowers, symbolizing power and respect in Feng Shui. The South, represented by the fire element, harmonizes with the hardy characteristics of giant ironweed, hinting at sturdy resilience amidst adversities. However, individual circumstances may influence this alignment, emphasizing the essence of personalized Feng Shui practice.

Fishtail fern evokes a harmonious interaction of Yin and Yang energies, contributing to balance and tranquility in a space. When situated northward, it symbolizes growth and progress due to its inherent wood properties, making it a fine choice for enhancing endeavors and projects especially related to career in one's life.