After defeating all mechanic bosses, summoners have few improvements in equipments. This cause it dull to defeat Plantera.
Chlorophyte Hood for summoners
Crystal Leaf can deal damage to enemies, which works like summon weapons. However, Chlorophyte armor isn't capable with summoners.If allowed, Chlorophyte armor could make whips more powerful, to make Chlorophyte armor an upgrade of Obsidian armor.
Hercules Beetle available before Plantera
Hercules Beetle is an accessory sold by witch doctor, but it is too weak for post-plantera challenges and it will be used only to be upgraded into Papyrus Scarab.The upgrade for summoner is needed when having defeated all mechanic bosses. It's advisable to make Hercules beetle available once all Mechanic Bosses are defeated, instead of Plantera.