Hi - My lupins have flowered well this year - I cut off the dead spikes and got a second flush. More or less finished now, but the remaining foliage and some new growth from the flower spikes are being badly attacked by white lupin aphids - I can't keep up with them by wiping off. It's August now - would it be OK to just cut the foliage right back? - I can see new growth at the base and it will be much easier to keep that aphid-free if all the ragged old stuff wasn't in the way.
Any advice appreciated :)