I am in the process of creating a Circle of Flowers subclass for the Druid. I'm trying to make them very in tune with the plants around them. They are also delicate and pacifist. I would also love to introduce some Charisma-based charm abilities. Maybe even the ability to Wild Shape into plants? 

Any ideas for features?

I was looking through the list of plants and there are almost none, so turning into plants probably won't be an ability.

Maybe unlimited speak with plants castings?

 So this is what I have so far. Feedback would be appreciated. Also, it says "This homebrew Subclass does not have the necessary class features with the correct required levels". Any ideas as to what that means?

Druids of the Circle of Flowers have a connection to the plants of the world. They embody the loveliness and charm of flowers, turning enemies to their will. Druids that follow the Circle of Flowers are not as connected to the entire environment as Land Druids, but they are especially attached to the flora.

Charming Presence

When you choose this circle at 2nd level, you gain the ability to unleash your charm. As a bonus action, you can attempt to charm a creature within 30 feet of you. The target must make a Wisdom saving throw against your spell save DC. If the creature fails its save, it is charmed by you for 1 minute. The effect ends if you or your allies damage the target. A charmed creature can repeat the saving throw at the end of each of its turns, ending the effect on a success. You can only have 1 creature under the effect of this feature at any time. You can use this feature a number of times equal to your Wisdom modifier (minimum of 1), and regain the ability to do so when you finish a long rest.

Infectious Charm

Starting at 6th level, your charm is more persistent. When a creature is charmed by your Charming Presence and succeeds on a save to break the charm, you can use your reaction to force a different creature within 30 feet of you to make a Wisdom saving throw or be subjected to the effect of Charming Presence. The duration does not reset; it continues from where it was when the original creature made the save. You can only use this feature once per use of Charming Presence.

Soul of Flowers

At 10th level, you can communicate with plants. You can cast speak with plants at will.

Plant Shape

Starting at 14th level, you can turn into plants. You can use your Wild Shape to turn into a plant creature with a CR as high as 3.