Toadflax brocade moth

Not a great year for purple toadflax here. Usually plenty of brocade moths and enough flowers for all of us. It was only when I had to rescue a lone caterpillar that there was hardly anywhere to put it, that I realised there isn't a lot of it about and no other caterpillars. I usually snip off the seeded shoots to get more flowers but perhaps I shouldn't this year.