Hi, Sheila,
Is it just untidy at this point? Most recommend deadheading at this time of year because if allowed to set seed, the plant will die. If you remove the flowers as soon as faded, you will extend the life of the plant. Then, you can go ahead and cut it back to 10-20cm in autumn. It it is unsightly, however, you can cut it back now.
Kathy C
Replied: Tuesday 5th of July 2011 09:19 PM
