I love that you're exploring Catalpa trees for companion planting! There's a lot to dig into here. While the idea of using Catalpa as a trap crop for pests like hornworms is fascinating, I've seen mixed reports on its effectiveness. Some say it attracts birds that control pest populations, which is a sweet bonus. What's super cool is that the caterpillars themselves are also considered great fishing bait, so there's that side benefit too!
As for allelopathic effects, studies are limited, but I'd be cautious and monitor closely in your specific garden environment. The leaf litter is nutrient-rich and might improve soil health over time, but just make sure it doesn't smother smaller plants. Keep us posted if you try it out-real-world experiments are the best way to learn!
