Smaller bunches 3-4 stems each, plant as deep as possible does not matter if majority of the stem goes into the substrate. Only a few leaves will be out of the substrate. This is still good.
What’s the height of the substrate and what type of aqua soil are you using.
Irrespective, bunches will come out of the substrate sometimea and you would need to keep planting till they take hold and spread. All the best!
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