Hi ravenpickers. I am so sorry I didn't answer your post. I don't know how I missed it.
I have problems every year with 'Pacific Hep', but I love it's spring and summer colors so much I keep struggling with it. It never seems to die out completely, and comes back on it's own.
What conditions have you grown it in? What growing zone are you in? And what growing medium are you using. It helps to know the specific of your growing conditions, maybe we can figure a way to have them grow for you.
Do you grow other semps?