I just collected them but should I wait until fall?
Here's a discussion on transplanting iris: https://www.gardeningknowhow.com/ornamental/bulbs/iris/dividing-transplanting-iris.htm
How do I replant irises ?
No, you should plant them now. This article as more information: https://www.gardeningknowhow.com/ornamental/flowers/columbine/columbine-flower.htm
Is it ok to plant in the fall. Will the cold weather affect it?
No, fall is not a good time to plant seeds. This article will give you more information: https://www.gardeningknowhow.com/ornamental/flowers/columbine/columbine-flower.htm
I have deadheaded the flowers but the foliage is beginning to turn brown and die. I am just not sure if I need to cut it for the winter or just leave it alone.
Columbine is considered a short-lived perennial, so many people allow the flowers to go to seed, thus reseeding itself each year. After the foliage begins to turn brown, you can cut it off and compost it (or throw it away,) or you can leave it in the garden to decompose back into the soil. This article has more information: https://www.gardeningknowhow.com/ornamental/flowers/columbine/columbine-flower.htm
Last year, I bought some Columbine seeds and planted them in a fixed windowbox. The plant grew very quickly, but produced no flowers. Then, in late October, it turned brown and the leaves shriveled, but did not fall off. It has been that way ever since. Granted, it has been a brutally bad winter and I did not cover the soil with straw.
Columbine is a biennial plant that does not flower until its second year. Columbines typically go dormant in the fall around October and their spring blooming is somewhat delayed compared to other plants, so this may just be a matter of having some patience. However, we can't ignore the fact that perhaps your columbine suffered a serious cold injury, but let's be optimistic! For information on how to save cold damaged plants, please visit the following article (I would follow the recommendation for watering and fertilizing):
When columbines go dormant and the leaves turn brown & dry like yours did, it's best to give it a "dead leafing" and take off all the foliage to keep the plant from looking too unsightly.
Your Columbine will grow up from the roots, if still alive, you should start seeing the leaves form at the soil level. Since it's in a container you will need to provide water.
Columbine growing in containers may be difficult. They would be happiest in ground.
Half of mine made it through our cold winter here. I'm zone 4.
I have to dig (install a gas line) in a bed of columbine. I want to save the seeds to replant the bed. How soon after blooming can the seeds be harvested?
Can you dig up the plants and move them to a new location?
You could try this first, if not go ahead and collect the spent flowers and just scatter on the ground in your new location.
It really is that easy, but here is a couple of great links.
Just had to do this same process last summer, good luck!
Once Columbines stop blooming, is the plant's foliage suppose to look unsightly, dying, and diseased? I have leaf miners, dead leaves and dead stems. Is there a way to maintain that fresh, green, full foliage or is this just normal? Also, how much should Columbines be watered/fertilized after blooming? Thank you for your help.
Cutting the plant back following blooming can normally help with most issues. Neem oil, which is both an organic insecticide and fungicide, sprayed on the plants is also recommended for most problems. Here is more information: https://www.gardeningknowhow.com/special/children/columbine-flower.htm
I have a bed of 4-5 yr old columbine that have flourished, blooms were abundant and about 6 ft tall this year, but they seem to be dying. I can find hardly any leaves at the bases of the plants as I trim the stems.
There could be a few different culprits to your loss of leaves on your Columbine plants.
Environmental issues could be a factor, heavy rain or extreme heat and dry conditions.
Have you seen any insects or caterpillars on the plants? Columbine Sawfly can feed on the foliage and strip the leaves very quickly and leave twigs standing much like the image you sent.
If you see the green caterpillars remove them and drop in soapy water. You can treat with Neem Oil.
Trim back the foliage in by half.
I would clean up any leaves that have dropped and dispose of. I would use the wait and see approach after treatment and see if the plants develop any new growth.