Question
Among my Iris this 3-4 foot stem appeared about 1 inch thick with buds up the sides and at the top. I thought maybe its a hoolyhock but the stem is very thick. i live in south new york state. Never seen a stem this thick and the buds are green, the stem is green. My husband says it reminds him of brussel sprouts.

Answer
Laura
Without a picture of the plant I can only guess and offer some ways to distinguish between the 2...
Brussels sprouts have bluish/green foliage....Hollyhocks have more of a standard green foliage look...
Brussels sprouts leaves are at the bottom base of the plant...Hollyhocks have more smaller leaves (shaped similar to maple leaves) on their stems...
Brussels sprouts produce yellow flowers...Hollyhock flowers are red,purple, white and pink...
Brussels sprouts have a very thick upward stem...As you stated hollyhock stems are much thinner...
Hope this helps...
Rick in southern NJ