Be thankful the photos in this post are not "scratch 'n sniff", voodoo lilies emit a very foul odor after blooming.
According to Paghat's Garden:
Northwest gardeners have reported them spreading quite wildly, & requiring no special attention of any kind. They spread by self-seeding & by bulb offsets. If the seedheads are not collected, they will eventually fall over in the garden, where beetles or ants cart them away, spreading the voodoo lily more distantly. The penultimate photo below shows one of the green seed cobs in August. The final photo shows the ripened cob in October, when the stalk has softened has toppled to the ground so insects will clean & disperse the seeds.
We've had these amazing plants slowly spread through our garden.
This Q&A from the Seattle Times recommends not planting these too close to your home, especially near dining areas or your doors or windows because of the smell and the insects that are attracted to the aroma (which only lasts a few days).
This isn't something you'll find in vase in my home! But I will tolerate the smell to adore their beauty. I was just out in my garden and had to share this with you!