Stanza 1 Summary

Get out the microscope, because we’re going through this poem line-by-line.

With blackest moss the flower-plots
Were thickly crusted, one and all:
The rusted nails fell from the knots
That held the pear to the gable-wall.

The poem opens with a pretty dreary scene.
We find ourselves in an old, abandoned farmhouse. Dark moss and rust cover everything, and the walls are collapsing
The flower pots are not growing any flowers. Nothing here has been tended to for a while, it seems.
The old structure isn't very stable, either. The nails holding the walls together are falling apart.
One thing is stable, though: the rhyme scheme.
Lines 1 and 3, and lines 2 and 4 rhyme; this is called an ABAB rhyme scheme.

The broken sheds look'd sad and strange:
Unlifted was the clinking latch;
Weeded and worn the ancient thatch
Upon the lonely moated grange.

Notice anything? The rhyme scheme switches up here. Now lines 6 and 7 rhyme. He has a plan, that Tennyson. Check out "Form and Meter" for the full scoop.
The imagery, however, stays pretty much the same. Everything is broken down and barely working.
And it's no wonder: nobody has been here for a while. The latch is "unlifted" on the gate.
There are some weeds that need picking, too. They're everywhere.
Something else that's everywhere? That would be wordplay. Lines 5 and 7 both play with alliteration, or the repetition of initial consonant sounds.
Just try reading them aloud. We'll bet "sad" and "strange" and "weeded" and "worn" prove to be a bit of a tongue twister.
Alliteration is just one way that poets add sound to their poems. For more, whistle your way over to "Sound Check."
One more poetic trick (and it's an important one) is the use of pathetic fallacy, or giving human attributes to non-human things. It's not as pathetic as it sounds, though. We promise.
To illustrate: here the grange (a country house) is called "lonely." It certainly fits with the tone of the poem so far, though we are betting this is more of an indication of how the speaker feels when looking at the farmhouse.
Some poets cautioned against it, but pathetic fallacy is actually pretty common among poets.
Clearly, Tennyson is a fan.

   She only said, "My life is dreary,
   He cometh not," she said;
   She said, "I am aweary, aweary,
   I would that I were dead!"

Ah, a human—finally.
It looks like a woman is inside the farmhouse.
From the title, it's pretty safe to assume this is Mariana. (Check out "What's Up With the Title?" for more on that.)
And, from the poem's epigraph, we know that she's the same Mariana that Shakespeare wrote about in Measure for Measure.
She's heartbroken and tired. Mariana has been waiting for someone who doesn't seem to be showing up any time soon. And she knows it, too, crying "he cometh not." Sad.