The traditional Hungry-Ghost Feeding rite is never done under or near a willow, peach, or pomegranate tree. This is because those trees have a purifying, vibrant field about them which is dissonant with ghost-fields. Ghosts are residuals or intelligent, or other kinds which are lost, confused, and suffering, and/or combinations thereof. Most trees and vegetation would be places where ghosts could take shelter and find refuge, but not so with the willow, peach, and pomegranate; those trees repel them.
The repellent effect of the willow is based on its being highly water-based, and it is the preferred tree of water-elementals and water-gods; water is the basis of all life, birth, growth, and sustenance, and its inherent vibrancy is frightfully overwhelming to ghosts. There are mystical legends, lores, and mythologies about the peach, especially in Asia; in Taoism, it is the fruit of longevity and immortality, the medicine of hermit sages; as a result of its powerful medicinal and mystical properties, the peach (both fruit and tree) is a ghost-repellent. The pomegranate likewise is the fruit of much bearing and seeds, hence, like the peach, it has the mystical property of pure life-potential; it is also the fruit of Hecate, one of the main divinities guiding the domain of ghosts, hence its divinely authoritative field, again, is a ghost-repellent. The fruits of peach and pomegranate, wands made of willow, peach, and pomegranate wood, are excellent tools for repelling and exorcising for the reasons just given.
If your activity is to attract ghosts, demons, signatures, discarnate beings, shadow-beings, inferior gods, et al. for whatever reason, they will not be summoned to the place of the willow, peach, and pomegranate. The best places are outdoors (never, ever indoors, and that is, never!) in flat, open areas, and the best times are during dawn (before the break of light) and during dusk (twilight).