|i planted dwarf fountain grass last year they reached a highth of 12|
I'm not sure what is up with the dwarf fountain. That is not at all normal and the only thing that comes to mind is something is wrong in the roots...killing roots, stunting roots, etc.
The purple fountain can get floppy if overfertilized. If you are happy with the results of yours when fed slow release products then you are on an okay track. Just don't apply too much. Excess vigor in fall can also reduce winter hardiness.
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