Q.Does star jasmine affect other plants growing with it?
I have a very healthy star jasmine evergreen however agapanthus growing beside it are not flourishing. Is there something in jasmine that disagrees with agapanthus?

Certified GKH Gardening Expert
I don't see any cautions about companion planting other than the other plants should have the same growing requirements. Jasmine will grow in sun, part shade or even shade and it's not picky about the soil. Agapanthus is the same although it does appreciate some compost occasionally and regular watering. Also, agapanthus needs to be divided every three years. Could that be the issue? The only other thing might be how close the two are together. Star jasmine does grow and spread. Here is more info:
https://www.gardeningknowhow.com/ornamental/flowers/jasmine/jasmine-companion-planting.htm
https://www.gardeningknowhow.com/ornamental/bulbs/agapanthus/agapanthus-plant-care.htm