Yes, it is best to cut every overgrown rosemary stem to make it the same length as the others. However, the method does come with a warning.
'Always avoid pruning the woody parts of the stems,' Bryan McKenzie, garden expert and co-founder of the Bumper Crop Times says. 'The logic behind the process is very simple. You cut down fresh growth to let the plant deliver more nutrients for hardening older growth and making it stronger against the environment.'