Will ants and aphids harm milkweed?
We have both common and swamp milkweed in the backyard. This year we have noticed ants and aphids in the plants. We understand about their symbiotic relationship but wondered if they would damage the plant or the monarch caterpillars. If so, what is the best way to get ride of them?
Pamela Hargest, Horticulture Professional
Sometimes aphids can cause damage to milkweed, but this isn’t always the case. Anecdotally speaking, I’ve never witnessed a situation where aphid feeding harms monarch caterpillar populations. However, since the Oleander Aphid (Aphis nerii) is an introduced species to the US, it doesn’t hurt to mechanically remove them from your milkweed plants. You can do this by simply rubbing them off the branch. I’d recommend wearing gloves since it can be a sticky situation!