I'm sure this poem was written by someone well-known and classic, but I can't remember the title or the author!

I believe in one stanza, he is describing her smile.....something to do with rows of oriental pearls, and rosebuds filled with snow.

Can anyone help? Thank you!

Well, it isn't Song of Solomon.

"Your teeth are like a flock of shorn ewes as they come up from the washing. Each one has its twin, not one unpaired with another."
Song of Solomon, 4:2 Jerusalem version.

It isn't Ezekiel 23:20 either !

There's no teeth in that verse. And it says donkey not mule. :-)

I've just done the obvious and googled.
From our Classical poet list.

There Is A Garden In Her Face
by Thomas Campion

1 There is a garden in her face
2 Where roses and white lilies grow;
3 A heav'nly paradise is that place
4 Wherein all pleasant fruits do flow.
5 There cherries grow which none may buy,
6 Till "Cherry ripe" themselves do cry.

7 Those cherries fairly do enclose
8 Of orient pearl a double row,
9 Which when her lovely laughter shows,
10 They look like rose-buds fill'd with snow;
11 Yet them nor peer nor prince can buy,
12 Till "Cherry ripe" themselves do cry.

13 Her eyes like angels watch them still,
14 Her brows like bended bows do stand,
15 Threat'ning with piercing frowns to kill
16 All that attempt with eye or hand
17 Those sacred cherries to come nigh,
18 Till "Cherry ripe" themselves do cry.

Thank you, Linda! This is indeed the poem I was referring to. Such lovely imagery...so romantic.