'Slowly along the munching English lane,
Like cows to the old shrine, until you lose
Track of your dragging pain.'

That should be 'mulching', shouldn't it? (Did nobody proofread Robert Lowell's Poems: A Selection, ed. Jonathan Raban?) though the dragging pain and big beasts might hint at anthropophagy rather than bacteriophages.
Looking up the page from 'Our Lady of Walsingham' to 'The Holy Innocents' I notice a 'clinkered hill' up which the year lumbers with losses. Shouldn't that be 'clinkered hull'? ... No. But I'm on my guard now. Next is the corpse in 'The Quaker Graveyard in Nantucket', 'its heel?bent deity' ?surely, surely that should be 'hell?bent'? And 'the coiled, hurdling muscles of his thighs'? Could it be 'curdling muscles'? Makes just a bit more sense to me. Maybe "eel?bent deity; I'll let anything pass after the 'ale?wife run' of the first poem.
A decent edition wouldn't solve the problem, which is that Lowell once said he hoped people would read his work and say 'that was one heck of a poet' or something of the sort (sorry, can't find the reference). He is one heck of poet. And he's always trying hard to stay one, putting an adjectival spin on nouns that would otherwise have been plainer. He polishes his work till the reader can see his face in it. Lowell's.
What is it about adjectives? Their syntactic redundancy (take them all away and the sentences still work), their prosthetic virtues (for dragging rhythms), the fact that they know their place and rarely come wide. All this was a boon to bards and other oral improvisers, giving poet and audience a moment's rest: the berry?brown gown or, south and east, the rosy?fingered dawn. People who read poetry, though, take their own time off. While the adjective still serves as a rhythmic and syntactic rest, it often takes a lot of semantic weight, or strain. Like when Ezra Pound alludes (in Greek) to the rosy?fingered dawn, telling us to think of Homer before breakfast, or when Lowell hits us with the above examples.
Fear not, this isn't a grand unified theory of epithets. It's just interesting to see that the disconcerting effect of Lowell's bravura is what language poets contrive by other means. Astounding adjective and noun pairs may be produced by the Poet of Genius ('the gun?blue swingle' or whatever you like); they may also be produced by the OULIPO S+7 method ('S+7 veut dire simplement qu'on remplace tous les substantifs d'un texte par le septième qui le suit dans un lexique donné'). This nicely sabotages the ego as the source of all poetry. It leads the unwary to conclude that the text, however produced, is all we should look at. Which is nonsense. I don't like feeling that a poet I'm reading is spending too much effort on impressing me; but better that than a nihilistic purveyor of text and nothing but the text (Ashbery). I've more sympathy for some of the language poets, but in the end 'change the language' is not what it's about. A quick look at three poets who could tell them.

Ah how bright the mantel
Brass shines over me.
Black?lead at my elbow,
Pipe?clay at my feet.
(W.S. Graham)

This whole business of epithets intervenes at a late (prolonged and tedious) stage of the poem's formation, when the plasma settles down into little nuclear families and the charges get distributed. 'Mantel' gives the brass an ingot shape, 'black' combines with lead to form a shining compound, 'pipe' reacts with 'clay' as candour, the honest ornament. There isn't an adjective in sight. The colours are all substantive. Remove them and the sentences collapse, the hearth with them.

How can adjectives be used in an essential way? Let's see if that's a fair question. Even in Graham's weird first collection, the adjectives aren't responsible for much of the disorientation: true there are bloodshot pennies, myrtle gospels and a nettle forefinger, but there are also limestone viaducts, a boatless sea, blushing joy and a gentle queen, all as reassuring as the conventional sentence structure. Adjectives are weak parts of speech and Graham doesn't overload them. Indeed, until "The Nightfishing" he's a bit too easy on them. And while "sheerhulk", "girlflowering" "mastertask" and the other Anglosaxoid shunts are looking for integrity, the epithets ? high, bright, new, black, white, blue, green, dry, terrible, dead, drowned ? are trying to forge the elements that he struck in the later "Malcolm Mooney's Land". Sleekit metaphor, not fair at all; it's just a way of saying I don't completely trust his words until then. And anyway, where's the law against putting a semantic load on a weak part of speech? It isn't a matter of law, but discretion. Lowell bends everything to his purpose ? that's his way. Graham tries to devine the language's purpose and go its way.

Outside the tent endless
Drifting hummock crests.
Words drifting on words.
The real unabstract snow.
(end of "Malcolm Mooney's Land")

'It must be abstract"
(Wallace Stevens).

Some critics like to lay down the law: never mind old plods like John Bayley. Look at Randell Jarrell, telling us bad poetry is not good and abstract poetry is not poetry (the latter a propos of Wallace Stevens, whose earlier work he praises highly). Well (A) most poetry is bad: it's a mug's game, and (B) the rest can be as it pleases: "The real unabstract snow" is utter abstraction, lyophilized.

Each Stevens poem is an abstraction, an architectural model on computer. The components can be either images or ideas, but the plan's the thing. "Poetry is the supreme fiction, madame. Take the moral law and make a nave of it. And from the nave build haunted heaven. Thus," thankyou. Epithets. There are two distinctive tribes in Stevens, the colours and the quizzicals. The colours are primary, and lights rather than pigments (the reverse is true of Graham), slanting in and suffusing the things ?golden floor, red bird, pool of pink, bright chromes, colored purple, white moonlight, green shade ? to look no further than the first twenty pages of the collected poems. And while the colour epithets show, the quizzicals see (light source and viewpoint respectively, in the computer image). "The Doctor of Geneva" has a swatch of them, as the good doctor is seen reacting to a new location: lacustrine man, multifarious heavens, simmering mind, unburgherly apocalypse. Stevens quickly escapes anything as crass as a scanning of his epithets, though the exercise confirms that he isn't content with making his poems: in his tremendous ambition that poetry succeed religion, he lets there be light on them with his "purple" adjectives, and he doubts and believes in them with his quirky epithets.

I had in mind a further manic leap, to Mandelstam, but I'm running out of steam. If Anglosax was WS Graham's handicap, then Greek (and Homeric epithets) was Mandelstam's. Still, it's nice to see how in the poem to JSB he sets up "O ratiocinatory Bach" (or "Most reasonable, judicious Bach") to increase the thrill of the punchline, with Bach "exulting like Isaiah", and in "I washed in the courtyard at night", how the epithet "coarse" applied to stars prepares for "In the rain?butt a star melts like salt". As he progresses, though, I can't easily distinguish what he's planned from what the language serves him. There are, for me, terrible difficulties in "The Slate Ode", because although Mandelstam's (anybody's) rhyme is exogamy that breaks the dominion of familiar etymological association, Mandelstam seems to reach far into the past of his words as well, where family is not familiar at all. Thus a lot of his weird findings, that have neither rhyme nor reason in a foreign language like English, turn out to have semantic precedents at home.

Flint meets water and ring joins horseshoe;
On the soft shale of the clouds
A milky slate?grey sketch is drawn.
(quoted from Osip Mandelstam: Fifty Poems, translated by Bernard Meares, with an introduction by Joseph Brodsky (New York, Persea Books, 1977)).

Now "persten'" (signet ring) is cognate with "perst'" (breast) (the ring being a nipple substitute, apparently), that goes with the "milk slate sketch" of the following line. And "kremen? (flint) is cognate with "shram" (scratch or scar), so that when at the end he writes:

I want to place my fingers
In the flinty path from the older song
As in a lesion

the thing begins to make sense. Begins to. Enough.

I am now in a position to conclude that there are at least four ways of skinning a cat, and that that conclusion
gets me no nearer the rough taxonomy I was out to establish. I don't think, anyway, that taxonomy would have shed any light on the light shed by certain poems, or that that would have been useful or possible. Escape. Save. Quit.