As I described in my other thread in this forum, last year I bought a package of five "Big Time Happy" Daylily roots from Longfield Gardens via Costco.

I'm confident Longfield Gardens is cutting such roots from the same source plant for a package of five. So it is nearly certain my five plants are genetically identical.

The first bloomed yesterday:
https://garden.org/thread/view...

The second bloomed today (sorry it wasn't practical to get a photo) and is a much paler bloom (many shades toward white from the yellow of the first one). Blooms are otherwise the same shape and size.

I expect the cause must be chemical (level of acidity and/or some extra or missing nutrient).

I have every reason to expect the soil to be near chemically identical in those two spots: Both in the same naturally very acid soil. Both with similar fractions of the same shredded leaves mixed in when I planted. Both with the same amounts of 10-10-10 added at the same relative position to the roots when I planted, and again under the mulch when they emerged again this spring.

But even though the chemical conditions ought to be the same, it is more likely the bloom difference is caused by a chemical difference.

It isn't really a problem. Mainly I'm curious about the difference and wondering if any of you experts have an estimate of what chemical difference is likely to be causing this.