Treacherous Ground shuts down Maeve's mobility quite handily if you can catch her with it, but be wary of nearby terrain. A smart Maeve can use some bits of map geometry to get above the effect of Warder's Field and become free from the cripple.
Maeve isn't actually strong aginst Maeve ,Inara has the slow deployable which slows in a short radius around her. This doesn't always work because it is stupid to verse a inara all by yourself when your maeve.
Two words. Street Justice. Poke from a distance until you, or someone else can get her around/below half health, and when she's not using earthen guard, pounce.