We did also recently get the Snowflower archetype which makes the Princesses significantly easier to make as a Deck if you splash a few of the Snowflower monsters in there... Just not anything competitive yet as the Princesses don't do anything game-breaking by themselves. (Yes, I have a build I attempted to modernize :P)
Now about the card itself: 3 of the Princesses off hand card be Special Summoned with the 1st effect via targetting other Princesses: just short of Chirubime whose DEF is 2800 instead of its ATK. Also, Talaya ATK gets boosted by herself being summoned so you can't target her to Summon another Plant Princess persay, however, you can Summon Mardel,_Generaider_Boss_of_Light which is notable to search out Lonefire, Snowflowers, another Princess, or Rose_Lover. I am not sure if the Extra Deck restriction is ideal though as you are already needing specific ATK stats to go into other Plant monsters with a different Attribute and specific Level range... That is already a hurdle in itself.
Last effect also includes a few lower Level Plants: Rose_Princess , Sylvan_Princessprite , and Sylvan_Princessprout for what that is worth. Trade-in and using the Plant Princess as Extra Deck Material makes that last effect live... So I see no problem there.
In all it is decent card, I would just get rid of the Extra Deck restriction on 1st effect.