Can i plant in soil where rosemary bushes grew?
Thank you for contacting the Toronto Master Gardeners. Dahlias do best in full sun, with some light shade if it gets very hot in the summer. Rosemary also prefers a full sun location, so if your rosemary bush was thriving in the spot where you want to plant dahlias, the light should be fine. Dahlias prefer rich well-drained soil, whereas rosemary does well in sandy well-drained soil. If your soil is sandy you might want to amend it with compost before planting dahlias. Rosemary prefers hot, dry locations, whereas dahlias need consistent moisture (must be well-drained though) and should not be allowed to dry out. In general dahlias will likely require more maintenance than your rosemary bush. In addition to more frequent watering, dahlias are more susceptible to disease and insects than rosemary.
Here is some information about growing dahlias that might be helpful :
Good luck with your dahlias !
April 11, 2021