My May Night Salvia blooms brilliantly throughout June- sunny spot, well drained soil. All under newly planted maple trees. They are doing well. I was told to deadhead the blooms when they are done. But the foliage turns a horrible grey then brown colour, dying back completely. Under though, is new foliage (green as if it’s spring again). Looks like new blooms coming up Am I deadheading at the wrong time? Should I be more aggressive? Maybe less?
Thank you for contacting the Toronto Master Gardeners concerning deadheading of your Salvias
Deadheading causes plants to focus on flower production. If you wait too long before you deadhead the plant will go to seed. This is what I suspect is happening to your Salvias. The infloresence stalks are just going to seed once they have finished flowering.
It is best to deadhead your Salvias in the middle of the summer once the flower spikes have begun to fade.. Fading begins from the bottom of the infloresence spike and moves upwards. Once 70% of the blooms have faded it is time to deadhead the infloresence. This could be a time-consuming process. Salvia infloresence are usually in clusters of thre, with a central stalk and two side branches. If allthe branches are dead then remove the entire infloresence, however if only the central stalk is finished cut off just the central flower while leaving any new blooms on either side alone. New blooms will usually grow off the sides of the stems.
There are a number of excellent Youtube videos on pruning Salvias, see https://www.youtube.com/watch?v=5EKy7eEbh9A&t=6s
Good Luck with your Salvias
August 15, 2022