I didnt know how best to describe this problem in the short allotted space in the title, so I'll do a better job now....

I have 7 plants now, and all have produced brilliant, bright colored flowers all along. But now, on 2 plants some of the flowers are starting to have washed out, diluted colored flower petals, which are too light.

One is called Macallister's pride. Its raspberry red from the end of the petals down to the base, with golden yellow only at the flower center. Its been blooming for 51 days with no problems. Its been a prolific bloomer too. I usually pick about 6-12 flowers per week, with only a couple weeks that were slower than that. But in the last 2 days, a few of the blooms are lighter and washed out looking, and their flowers are a good bit smaller too. Another problem, is that they have more and more yellow than before. The yellow is further and further up the petals. Plus, some flowers are opening unevenly, with only one side opening up and growing properly, and the other side taking a while to catch up, but ending up a bit uneven. This has all started in the last 2-3 days.

The other plant is Fuzzy Wuzzy. It is medium hot pink with pure white only at the very ends of the petals. Some flowers have no white tips, some with only a few white tips, some with all white tips. Thats been going on since they began blooming 40 days ago, but now more flowers seem to have the proper white tips, so thats a good thing, but there are a few new flowers that are washed out looking on the pink areas, with it looking too light. This began 2-3 days ago also. Its not been a prolific bloomer, but now its starting to grow more flowers.

I have another dahlia called Crazy Legs that was planted at the same time as the other 2, and its been blooming for about 45 days. Its always been a very prolific bloomer, and it doesnt seem to be having any problems with washed out looking flowers, as its colors are still brilliant. The same is true of the other 3 large dahlias I started 2.5 weeks after the above 3.

But there is 1 smaller dahlia I planted 23 days before all the rest, which is only about 28-30 inches tall. Its been blooming for 2.5 months solid, and its flowers are a bit small now, and a few have been washed out a bit too. Its also a prolific bloomer.

What could be causing the washed out looking flowers? Like I said, of the main 2 plants effected, one is a prolific bloomer, and the other one hasnt been prolific, but is only now starting to grow more flowers in the last 5-6 days?