I've got two pots with sweet peas of the same variety, grown the same way at the same time, but one lot have got much longer stems than the other, and the ones with the shorter stems are now getting attacked by greenfly. The only difference is that the shorter-stemmed ones are in a less sheltered spot. Could that make a difference, and if not, any ideas? Trouble is, the short stems are really too short to make good cut flowers, but it's a shame to cut them & throw them away just to keep it flowering.