Sonnet LIV

O! how much more doth beauty beauteous seem
By that sweet ornament which truth doth give.
The rose looks fair, but fairer we it deem
For that sweet odour, which doth in it live.
The canker blooms have full as deep a dye
As the perfumed tincture of the roses,
Hang on such thorns, and play as wantonly
When summer's breath their masked buds discloses:
But, for their virtue only is their show,
They live unwoo'd, and unrespected fade;
Die to themselves. Sweet roses do not so;
Of their sweet deaths are sweetest odours made:
   And so of you, beauteous and lovely youth,
   When that shall vade, my verse distills your truth.

The youth is praised not only for his beauty, but for inward truth as well. Those whose beauty is composed only of externalities are compared to wild and scentless roses, whereas those who have inward worth, like the youth, are compared to true roses, which are grown for their scent as much as for their looks.

The comparison of the young man with a rose is a constant motif throughout the Sonnets, commencing with 1, then here, and in 67, 95, 98, 99, and 109. In 67 it is also combined with truth.

The 1609 Quarto Version

OH how much more doth beautie beautious ſeeme,
By that ſweet ornament which truth doth giue,
The Roſe lookes faire, but fairer we it deeme
For that ſweet odor,which doth in it liue:
The Canker bloomes haue full as deepe a die,
As the perfumed tincture of the Roſes,
Hang on ſuch thornes,and play as wantonly,
When ſommers breath their masked buds diſcloſes:
But for their virtue only is their ſhow,
They liue vnwoo'd, and vnreſpected fade,
Die to themſelues .Sweet Roſes doe not ſo,
Of their ſweet deathes, are ſweeteſt odors made:
   And ſo of you,beautious and louely youth,
   When that ſhall vade,by verse diſtils your truth.

Commentary

1. O! how much more doth beauty beauteous seem
beauty - beauty in the abstract; your beauty; you yourself, being such a beautiful person.
2. By that sweet ornament which truth doth give.
By = as a result of.
that sweet ornament = the wonderful additional beauty and sweetness etc.
Truth adds further to beauty's beauty as an ornament makes a person or thing more beautiful. Perhaps from this sonnet, Keats fashioned his line Beauty is truth, truth beauty, in the Ode to a Grecian Urn.
3. The rose looks fair, but fairer we it deem
but fairer we it deem = but we consider it to be more fair
deem
= think, consider.
4. For that sweet odour, which doth in it live.
For = because of, as a result of.
5. The canker blooms have full as deep a dye
canker blooms = dog roses, wild roses, (See illustration above). Rosa canina; Compare:
To put down Richard, that sweet lovely Rose,
And plant this thorn, this canker Bolingbroke
. 1H4.I.3.176-7.
as deep a dye
= as rich a colour.
6. As the perfumed tincture of the roses,
tincture = dye, colour. Also, because of the subject matter of the previous sonnet, there is probably a reference to the alchemical meaning of 'the spirit or quintessence of an object'.
7. Hang on such thorns, and play as wantonly
Hang on such thorns - the subject is 'the canker blooms'. Their stems, on which they hang, are just as thorny as true rose stems.
play as wantonly - the wind plays wantonly with flowers and leaves, making them dance and sway. wanton suggests sexual license, and the implication is that the canker blooms are as wanton, if not more so, than the roses. Shakespeare does not use wantonly elsewhere, but his use of wanton is frequent. See the following examples:

Adonis painted by a running brook,
And Cytherea all in sedges hid,
Which seem to move and wanton with her breath,
Even as the waving sedges play with wind.
TS.Ind.2.48-51.

So are those crisped snaky golden locks
Which make such wanton gambols with the wind,
MV.III.2.92-3.

8. When summer's breath their masked buds discloses:
summer's breath = the breezes of summer;
masked buds = buds covered with sepals. The metaphor is of masks worn by ladies at a dance, their faces being unmasked by persuasive wooing.
discloses = reveals, opens.
9. But, for their virtue only is their show,
for - because, since;
their virtue only is their show = their show (appearance, display) is their only virtue (essence, nature, power). I.e. they are a sham. The word order is reversed, suggesting almost the opposite, that they reveal true virtue, perhaps with the intention of intimating that it is easy to be deceived by appearences.
10. They live unwoo'd, and unrespected fade;
They live unwoo'd - Although the wind plays wantonly with them (the canker buds), it is not serious wooing with the intention of marriage, and therefore they are left on the shelf.
unrespected = unnoticed, treated without respect. See 43.2.
11. Die to themselves. Sweet roses do not so;
Die to themselves = Left alone they die, having no contact with the wider world.
Sweet roses - in contrast to the canker blooms, which are not sweet. do not so - This is at first read as if it were an imperative, or an earnest request, 'Do not cast yourself away so profitlessly', an echo of 1-17. Then, with the subsequent line, it transforms into a simple statement - 'Roses do not behave like this. They are productive etc.'
12. Of their sweet deaths are sweetest odours made:
are sweetest odours made - Rosewater was a distillation made from rose petals. It was an important ingredient in the preparation of some confectioneries and kissing-comfits, used for sweetening the breath. It was also used for perfumes.
13. And so of you, beauteous and lovely youth,
lovely = adorable, worthy to be loved; beautiful.
14. When that shall vade, my verse distills your truth.
that - youth, or beauty, or both. Either as the subjects of the poem in general, or by transformation from the previous line, whereby the implied perfections which enable him to be addressed as 'beauteous and lovely youth', become abstracted and are found to be qualities which will perish with time.
vade = fade, depart, lose colour. A variant form of 'fade', or a word derived from Latin vadere to go.
my verse - Q gives by verse which requires that one reads distills as an intransitive verb, i.e. 'Your inner truth is distilled by verse'. I have opted for the emendation to my on the grounds that it echoes the sentiment of many of the other sonnets praising the youth's excellence, 17-19 for example, and it chimes better with the following sonnet.