"Why should this desert be?"
Rowe read 'a desert'; Tyrwhitt 'silent be.' I rather prefer the latter; but it is against it that, excepting in one of the following and the six last lines, the first foot is always monosyllabic. I have therefore followed Rowe.
"Or at every sentence end."
For 'Or' I read And. (See Note at end of Samson Agonistes in my Edition of Milton's Poems.)
"It may well be called Jove's tree when it drops forth fruit."
The 2nd folio reads 'forth such; Capell read such for 'forth.' Perhaps the first is to be preferred; yet I find I have followed Capell in my Edition.