Answer: Morning Glories are relatively easy to grow; provide well draining soil and keep the plants watered and they should grow right up the fence for you. You'll want to dig out any weeds in the planting site and after planting your morning glories place a weed barrier or several thicknesses of newspaper on the ground and cover them with decorative rock or bark to suppress weeds near your new morning glories.
As for the weeds popping up in the lava rock, you can spot treat with an herbicide such as Round-Up or you can pour boiling water on the weeds to kill them. There are pre-emergent herbicides you can apply which will keep weed seeds from germinating.
Best wishes with your landscape!
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