Yes, you can wick large plants from the top of the pot! I watered large Passifloras that way! Just insert the tip into the top of the soil , and perhaps coil the wick a bit snake-wise over the whole pot surface before placing the other end into the water bucket. I guess, one simply has to follow the old "communicating tubes" principle/ match the depth of both ends of the wick in such a way that water is properly flowing or better even, dripping. ( Keeping the tip of the wick in the water bucket at the bottom of the bucket) Soaking the cotton shoelaces first before inserting will start things up easier.
