@chai2,
Pruning t-shoots develops horizontal (lower) growth in shrubs and trees.
Covering increases humidity which allows for optimal (above) - Same as cloning/cuttings.
30 days is a reasonable period for roots/shoots to develop in older plants.
I clone for 45-60 days - Equatorial shrubs can develop quicker.
And feeding 'Nitro/phospho, etc is detrimental to young spurtage.