Gaillardia can be problematic in clay soils because they tend to be poorly drained. However, they despise overly rich soils too.

Their biggest death threat is wet winter soil. Clay tends to hold plenty of water in winter. So, you have to be prepared for some losses in that clay border. They benefit from being sheared down to about 4" right now so their rampant flowering doesn't threaten their winter survival. Let them build up some dense basal foliage before frost and they have a better chance to make it.

Given that I have 2 stands of Gaillardia, one in clay and one in rich I am thinking that any losses of plants over the winter in the clay garden could be replaced by those plants that may more likely to survive in the heavily amended soil.

But I am interested in your advice re a shear back now to help with winter. You are right in that they are flowering so much still but as well they seem to have lots of basal branching right now. Anyways I will try to post a picture later today and you can see what you think.

What I would do then is just cut down to that dense foliage (removing all flowerheads and buds), especially given you are in Zone 5 and your first frost will probably be earlier than ours here in Zone 7. Unfortunately, you do give up some late-season flowering to get a plant with a better shot at making it through winter. The other option is to leave them be and take your chances. If you lose plants, you should still get plenty of seedlings in Spring, though Gaillardia cultivars such as 'Arizona Apricot' do not tend to come true from seed (from what I have read/seen on here).

Also, keep in mind that just because you have clay doesn't mean it isn't well-drained soil. If it is amended nicely and/or isn't compacted, it may drain just fine. Some clays (like mine) are literally like potting clay -- you can pour water in a hole and it is still there hours later. Others drain pretty well. Good luck!

So is the reasoning that by cutting back flowerheads and buds at this time of year will encourage the plant to put its energies into below the ground activity i.e. root growth?

Is this the case for all herbaceous plants?

Great questions. It isn't primarily for root growth, though the plant would probably redirect energy there too. Cutting back the flowering/budding stems is supposed to encourage basal foliage growth which apparently creates a more robust plant that can better handle the winter. Sometimes these perennials put so much energy into flower production that the plant sacrifices its own vigor for the sake of reproducing. This doesn't apply to all perennials, but they tend to be long-flowering and short-lived varieties such as Shasta Daisy, some Coreopsis species, and Centranthus ruber. The thinking behind this strategy originates from the book Perennials and Their Garden Habitats by Richard Hansen and Frederich Stahl.

Of course, feel free to experiment and see what works for you.

I have 1 Arizona Sun for the last 5 years and it came back every year, on mended clay soil. I do not do anything special prior to fall and winter time. However, I do notice that the new plant emerges pretty later in spring. Actually every spring I thought I had lost it but it came back, first as very tiny little plant, most likely from seeds. So if you do not see them emerge next year, be a little patient give them a little more time to be sure. This spring I almost planted something over it as I was not sure if it is still alive or not. Tt was as tiny as my finger nail but grew to be a regular plant in no time.

Since you have several Arizonan Apricot, you can experiment different things and see how they work. But please do post back with your results next year so we can all learn.

Best of luck,
Vivian

Thank you mistascott for your follow-up and I will report back Vivian next spring.

Here is one of my ten AA as of today. They are all in clay soil.