‘Tis hard bewildering riddles to compose
And labour lost to work at nonsense prose.

[Turpe est difficiles habere nugas,
Et stultus labor est ineptiarum.]

Martial (AD c.39-c.103) Spanish Roman poet, satirist, epigrammatist [Marcus Valerius Martialis]

Epigrams [Epigrammata], Book 2, epigram 86 (2.86.9-10) (AD 86) [tr. Francis & Tatum (1924), #105]
    (Source)

Discussing writing elaborate or highly stylized poetry forms. (Source (Latin)). Alternate translations:

Disgraceful 't is unto a poet's name
Difficult toys to make his highest am:
The labour's foolish that doth rack the brains
For things have nothing in them, but much pains.
[tr. Killigrew (1695)]

How foolish is the toil of trifling cares.
[tr. Johnson (1750); he credits the translation Elphinston]

How pitifull the boast of petty feats!
How idle is the toil of mean conceits!
[tr. Elphinston (1782), 2.76]

It is disgraceful to be engaged in difficult trifles; and the labour spent on frivolities is foolish.
[tr. Amos (1858), 2.19]

It is absurd to make one's amusements difficult; and labor expended on follies is childish.
[tr. Bohn's Classical (1859)]

'Tis mean and foolish to assign
Long care and pains to trifles light.
[tr. Webb (1879)]

Disgraceful ’tis to treat small things as difficult;
‘Tis silly to waste time on foolish trifles.
[ed. Harbottle (1897)]

'Tis degrading to undertake difficult trifles; and foolish is the labour spent on puerilities.
[tr. Ker (1919)]

'Tis hard bewildering riddles to compose
And labor lost to work at nonsense prose.
[tr. Francis & Tatum (1924)]

It's demeaning to make difficulties out of trifles, and labor over frivolities is foolish.
[tr. Shackleton Bailey (1993)]

It is absurd to make trifling poetry difficult, and hard work on frivolities is foolish.
[tr. Williams (2004)]

The Latin phrase was used by Addison as the epigram of The Spectator #470 (29 Aug 1712).