more info please ...

are you growing these in the house???? ... greenhouse.. ????

window light.. supplemental light ...

why would it need all that fert in winter.. in the northern hemisphere???

outdoors.. it would be dormant ... can it be grown year around??? ... does it 'need' a dormancy period??? .... i dont know ...

have you considered.. that you might be loving to death ... an endemic mud weed .. lol ... your media.. seems way beyond.. what you call.... 'thick, smelly mud'

i am just brainstorming for you ... sorry i cant give you a specific answer ....

ken

I've never containerized it, here our western version just grows on its own ;)

Is that a mulch layer on top your potting medium or the medium itself. Their native soil would be very heavy (not chunky with bark) with organic matter, on the acid side due to the decomposition of that organic plant material.

The coloring of the leaves suggests chlorosis. That can be wrong soil ph, but anything that damages roots leading to their inability to take up nutrients can cause chlorosis too...like soil too wet/dry, nematodes, and fertilizer burn. Weekly fertilizing sounds excessive to me, maybe about 4 times too excessive. Have you checked the root systems on any of your plants? It should be extensive with skunk cabbage - larger than you might expect given the plant size.

Leaves will indicate nutrient problems quite early, but diagnosing the problem can be difficult. Yellowing of leaves, often thought to indicate a Nitrogen deficiency has many causes including Iron deficiency. It is known that soil pH plays a major role in nutrient availability and that excess amounts of a nutrient can interfere with a plants ability to use others.
I would guess that since the OP is in Zone 5 that this is a houseplant, or maybe a greenhouse plant, which can indicate a whole bunch of other problems.

Here is a link that might be useful: leaves as indicators of nutrition

These plants are being kept indoors under T8 lights. The bark mix is the potting substrate, not just a top layer--I considered their natural habitat and soil type, but decided this mix would be best as it allows me to flush excess salts easily. The fertilizer schedule is not as intense as it might sound; they are given the recommended concentration and then sit in a container of water in which the nutrient solution is further diluted.

I've done a bit more reading after posting this and I believe, as you folks have mentioned, that pH may be a problem here. The fertilizer (Foliage Pro) contains all macro- and micronutrients in proper proportions. I'm going to try lowering the pH with vinegar and see how that helps.

The browning along the outer edges of your leaves looks more like fertilizer injury than ph issue.

I use any fertilizer product including Foliage Pro mixed at no more than half strength of the directions on the package, usually less than that. Nothing I've grown in containers (meaning countless perennials and shrub starts) has shown symptoms of needing more, ever. About once a month during the growing season only.

You may need to rethink your growing medium and for this particular plant, try to come closer to the natural preferred soil. Ease in flushing salts for you won't be helpful if the plant won't thrive in it ;)

Good point. Do you think I should try to approximate its natural soil in terms of water retention only, or in content as well?

Hi I leave in the north east of England , I've planted this plant in 3 different areas of my bog garden, with no success , they grow but never flower, what I'm I doing wrong

there might be a pond forum .... ken

They all died and I pretty much have given up on trying to grow more. I was actually thinking about this problem a couple of weeks ago though, and I think part of the issue might be the difference in redox conditions in my setup versus their natural habitat. For anyone without much of a chemistry background, my line of thought is that in their natural habitat (permanently saturated wetland), soil conditions are highly reducing--hence why that sort of habitat smells like rotten eggs (sulfate reduction to hydrogen sulfide gas). There would have been plenty of oxygen in my setup, even though parts of it were saturated most of the time, and certain oxidized ions (eg, iron) are significantly less soluble than their reduced counterparts. It's possible that differences in ion dissolution or precipitation could have led to nutrient deficiencies for my skunk cabbages. It's also possible that these differences could have changed pH enough to lead to nutrient deficiencies.