Poplar

'Populus'' (known commonly as Poplar) is a genus of 25–35 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere.

Wandlore
“If you seek integrity, search first among the poplars,” was a great maxim of Gerbold Ollivander, a saying that Garrick Ollivander supports based on his experience of poplar wands and their owners. It is said to be a wand to rely upon, of consistency, strength and uniform power, always happiest when working with a witch or wizard of clear moral vision.

There is a tired old joke among lesser wandmakers that no poplar wand has ever chosen a politician, but here they show their lamentable ignorance: two of the Ministry’s most accomplished Ministers for Magic, Eldritch Diggory and Evangeline Orpington, were the possessors of fine, Ollivander-made poplar wands.