Q.Do any types of palm trees exhibit allelopathy
We have attempted to grow petunias and salvia in a ring around some palm trees. They are NOT thriving and some are dying. The palms in question either are or resemble a triple-stemmed “Christmas Palm.”
Here is an article that discusses the challenges of gardening under palms and various workarounds. Basically your plants might be struggling to compete with palm roots . Also - the soil under palms is dry and nutrient deprived.