A321 flight crew reported temporary loss of control in the climb due to severe turbulence.

Narrative

ZZZ-ZZZ1 New Hire FO IOE; A321. Encountered severe turbulence on ZZZZZ RNAV departure climbing through approximately 17;000' MSL. No injures reported. All flight planning data called for a rough ride out of ZZZ westbound. Flight Attendants were briefed to remain seating until notified it was safe to commence inflight duties. Upon handoff to ZZZ Departure we were notified of continuous moderate turbulence from 14;000-19;000 with a report of severe turbulence from an ERJ at 17;000' as I remember. I directed the PF to slow to 275 KIAS for A321 severe turbulence penetration speed and select tracking to accelerate climb above reported turbulence. At approximately 17;000' MSL we encountered the severe turbulence resulting in uncommanded Autopilot disengagement. FO assumed control of aircraft but was unable to effectively control pitch or airspeed. 20 knots loss initially and loss of established climb to level flight and then 30 knot increase before pitch control was reestablished. Once climb was reestablished aircraft climbed out of turbulence approximately FL190. Duration was approximately 45 seconds to one minute. No inflight airspeed limitations were exceeded. No injuries reported by Flight Attendants or passengers. ATC and dispatch were notified. Rest of flight was uneventful. Maintenance was notified of the requirement of a severe turbulence inspection. When greeting passengers during deboarding no concern was reflected by anyone and some thought it was quite exciting. Maintenance download reported G loading was .24 to 1.73 Gs. My bad; I did fail to contact the Chief Pilot before continue to next flight.