Good Morning, 

Thank you for contacting the U of M Extension Service. 

I am not familiar with pourable mulch. Is the vegetation barrier pourous to allow the moisture to pass through? It should be. 

Here is a link about watering newly planted trees: https://extension.umn.edu/planting-and-growing-guides/watering-newly-planted-trees-and-shrubs

I would ensure the mulch you have applied allows water to seep into the ground around the trunk of your trees. A good wood mulch, applied within the drip line of the tree, a few inches deep and a few inches away from the trunk of the tree. The mulch will keep the soil cool and moist and protect the roots. If the vegetation barrier is not allowing air movement and water movement, I would remove it. 

I would prune off the shoots coming out of the ground. Ensure there is at least a thin layer of good compost or soil over those roots, and apply wood chip mulch. 

Here is another valuable link about pruning trees: https://extension.umn.edu/planting-and-growing-guides/pruning-trees-and-shrubs

Good Luck!