Should I get rid of this caterpillar that's on the silver leaf plant? When do you leave them to turn into butterflies?
Unless you are seeing unsightly damage, I would suggest leaving it. Caterpillars will only pupate when they have eaten their fill of their host plant. Unfortunately, the caterpillar is out of focus so can't identify but you might find it here:
A trowel in the hand is worth a thousand lost under a bush.
Leave it if you can. If you can identify it, you may be able to find its normal native food plant. Pop a few in as a distraction. We had amazing hawk moth caterpillars on night scented stocks one year.
I have a feeling unless there is evidence otherwise such as damage on that particular plant, that it has just climbed up there ready to pupate, rather than actively feeding on the plant.
Thanks, GemmaJF. Unfortunately, it has gone but I know for next time to check its identity (thanks BobTheGardener).