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An Anthocharis cardamines spends most of it's life cycle as a pupa between midsummer and through to the following mid-April, before becoming an Orange-tip butterfly.
Assuming a final instar larva left it's host plant to pupate, I was thinking about possible, suitable plants that a larva might prefer to pupate on, or suitable flora, that might be chosen, with the flora remaining standing and larva was relatively safe, as camouflaged. Hopefully, they might also avoid being weeded, if flora was more aesthetically pleasing during late winter and early Spring, than other flora.
Does someone have experience with suggestions, please, including possibly not cutting, native long grass?

Because of evolved success rates to imago (adult, sexually mature butterfly), does the final instar larva, have a tendency, to seek out plants with slightly more structural longevity, for pupation?

My findings from this year (2021) found that OT larva had a tendency to choose woody stems or twigs (those parts of a plant that were not this years green growth) 3-5mm diameter twigs chosen, appeared to allow the caterpillar to fasten the base of it's abdomen all the way around the woody stem When choosing an older (woody stem), I thought this left a bit of a grey area in biennial and perennial plants left standing over-winter.

Why was this important?
Understanding where an OT larva might want to go, could be like telling it where to pupate in a garden design, with it's primary larval food plants.

That's very useful to know. The orange tip larvae in our garden always leave the garlic mustard plants and this might help me locate them.

Guy

For my small scaled annual breeding of Orange Tips, when in final instar, I put some hard (and durable) twigs in the box. They always use those for pupation.

In the wild, I have more often found eggs near to hedges or some other sort of vegetation that will survive the following winter.

Jack

Found this at Bookham today, I've been keeping an eye on some when I visit. Some may remember I found two pupae attached to Garlic Mustard stems last winter. Also of relevance to this thread, the 4 that I reared at home this year all pupated on the glass sides of the cage I had them in during their last instar, despite the provision of plenty of twigs.

The Anthocharis cardamines (Orange-tip species)
I observed (approximately 100 larvae, where about 10 were seen in pupation, locally near Lincoln, Lincolnshire) had a tendency to choose a "woody plant", rather than a Garlic mustard stem, where they might have been, rarely successful in tidy gardens.
Also a larva was clearly seen fixing it's abdominal base by wrapping silk all the way around a 3mm or 4mm woody stem (any larger stem, the larvae might not have got the silk, all the way around the stem for an overwintering, firm, about 10 month fix).

Nearly everything to me, suggested that an Anthocharis cardamines (Orange-tip species) was most successful to life cycle with Garlic mustard, next to a "woody hedge" (or similar). Local observations showed me that Garlic mustard was grazed the most by larvae in at least part sun (try West facing, afternoon sunshine) and the plant thrived the most in the shade (north facing). At least four of our native butterfly species, life cycle grazing this plant. When butterfly species were very successful, plants that were left included Wood avens (not grazed from my observations), so be prepared to sow Garlic mustard seeds and do some selective, garden weeding (a weed being a plant growing, subjectively in the wrong place).

"A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposite to herbaceous plants that die back to the ground until spring."
- Reference wikipedia November 7th 2021 (search "woody plant").

Garlic mustard and Honesty were biennial, some "bolted "structure, naturally survived a winter, with some harder material near the base. In a field of Cuckooflower (Cardamine pratensis) or Garlic mustard, where there was little "woody plant", I thought that the butterflies showed little discrimination between different plant locations, apart from a butterflies tendency to follow in flight, a sheltered, sunny hedge line.
A conclusion was that Anthocharis cardamines did life cycle around without 3-4mm diameter woody material for pupation, but they might have been considerably less naturally successful there, as a percentage of 4th and 5th instars seen.

Most of my observations were not with Cuckooflower (Cardamine pratensis).
Related short video:
https://youtu.be/uOBqik_zEkI

Kind Regards.