Honeysuckle

I have 2 honeysuckles (can't remember the variety), one either side of a narrow pergola opening, i.e. about 6-8 feet apart.  One is always absolutely covered (overnight) in aphids at this time of year and the other never.  This year, the aphid problem seems even worse but the usual heavy spray yesterday evening seems to have done the trick as usual - and I won't have to do it again.  There is not a sign of them on the rambler planted very close to it, nor even on the lupins (6 feet away), which can often suffer the same fate.  Is there any particular reason why 2 plants of the same variety should differ so?