Greenbell gets -15% as well so she's basically magic Dahlia (same abilities but Greenbell starts with -15% for two pests instead of +10% squad attack power, slightly weaker skill but +4% base skill proc chance).

...I should work on getting Greenbell into fighting shape so I can bolster my secondary debuff team. Kerria has New Year's Ivy/Snowdrop/Bride Oncidium/Cherry for a -65% debuff and with Greenbell/Cherry Sage/Dahlia I could give Alpinia a -40% buff to work with.