I generally allow silene to set seed, then pull out the rosettes, which just get tattier. They only have one bloom cycle, regardless of how punctilious we are, regarding dead-heading or cutting back. Foxgloves have behaved like short-lived perennials, although I never expect more than one flowering spike (although it may throw sideshoots). I also cut the spike down before it sets copious amounts of seed...which may allow the plants to sustain enough energy in the roots for another growing season.

I am also frequently confused kitasei, since quite a few plants sown as biennials will return for another season (if not allowed to run too much to seed - erysimum, hesperis, verbascum, digitalis, ...while campanula medium, and pyramidalis, forget-me-nots, lunaria act like true biennials - producing foliage in year one and flowering, setting seed and dying in year 2. I have always considered hollyhocks to be short-lived perennials - plants which will take 2 seasons to reach flowering maturity but will return thereafter, although will benefit from regular re-sowing.

Likewise. Although I have Hollyhocks which are several years old. I leave all three to self seed within reason.

Biennials and short lived perennials confuse me.

OT@kitasei, but evolutionary wise, I do wonder sometimes the 'advantage' of a plant being a biennial or short lived.

The question intrigued me too so I looked it up. The advantage is a sturdier root system making them more resistant to drought and cold, and superior seed dispersal.

I tend to leave mine be to self-sown. The flower ones at least. The edibles like alliums I dig up and re-sow every year. I want the underground bits on those rather than the pretty flowers and seeds, heh.