POPULUS X JACKII - 'NORTHWEST' POPLAR - a large, spreading, straight trunked tree which may reach 70 feet in height on favorable soils. Young trees pyramidal in form. Originated from a natural cross in North Dakota between P.deltoides and P.balsamifera. Greater drought tolerance than other poplars, very susceptible to leaf rust and bud-gall mite. Root suckering can be a problem with mechanical cultivation.