The word winterberries is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 20
Highest Scoring Words With Friends™ Plays In The Letters winterberries
:
Seven Letter Word Alert: (52 words)
berries, bestrew, between, bitsier, bitwise, brewers, brinier, eeriest, enterer, entrees, entries, inerter, newbies, newsier, rebites, reenter, reinter, renewer, renters, rerents, rerinse, retiree, retirer, retires, retrees, retries, retwine, rewires, rewrite, serener, sneerer, steerer, sterner, stirrer, sweeten, sweeter, sweetie, teenier, terrier, trienes, twiners, website, weenier, weiners, western, wieners, wienies, winiest, winters, wiriest, wrester, writers