I.up [美 əp, 英 ʌp]副up often appears as the second element of certain verb structures in English (back up, pick up, sit up, etc). For translations, see the relevant verb entry (back, pick, sit, etc).
Leaves poke up through the ground in late summer, take a rest or even die back a little when temperatures plummet in winter, and resume growth in spring.
But when you build something that is going to poke up through and get hit by the jet stream from time to time, then it becomes shockingly much more difficult.