What's wrong with these two delphiniums? (manure, containers, compost, root)

[las14]

I was happy to see that 12 of my 14 delphiniums survived the winter. But two of them are stuck at two inches tall. As far as I know they were given the same treatment as the others, composted manure top dressing in the fall, spray with H2O2 to keep away fungus (seems to be working).

There are two pictures of stalled delphs, and two of the other healthy ones for comparison.

Any ideas?

[Northrick]

In the third photo the "pipe" protecting the start is blueish on the outside. Is that copper? If so, that might be part of the problem.

[Zoisite]

I'll suggest you get rid of the toxic rusting metal and don't do that again.

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[Lodestar]

I'm admiring your moss and lichen covered rocks. Been trying to achieve that look in one part of my gardens but so far nature has other plans.

[elnina]

Environment. The first two seem to be happily thriving in the ground, the other two are suffering in some sort of rotten containers...

Is this your thing to start a thread and never come back?

[Zoisite]

Originally Posted by elnina

...... Is this your thing to start a thread and never come back?

Uummm, I suspect there's something not quite right with the OP's memory. The conditions described (and especially the photos of delphinium root balls placed inside rotting metal paint cans) tell a strange story of peculiar gardening behaviours. And OP has asked 7 questions in 7 posts since 2017 but has never returned to any of the threads she/he has started. So I think the person is forgetful about their posts and gardening hobby and maybe won't be back for another long while again if their posting history and gardening behaviours are anything to go by.

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