Iris tuberosa (formerly Hermodactylus tuberosus) is a species of non-rhizomatous plant of the genus Iris, with the common names snake's-head,snake's-head iris,widow iris, black iris, or velvet flower-de-luce.
"This species of Iris, readily distinguished from every other by its quadrangular leaves, is more remarkable for the singularity than for the beauty of its flowers; yet, to some might not apt to be caught by gaudy attire, these sombre tints have their charms. In this respect it strongly contrasts with our next figure.
It is a native of the Levant, and with respect to the cold in our climate is perfectly hardy, flowers best, according to Miller, in an eastern aspect, and if the soil be light it would be proper to put some rubbish at the bottom to prevent its roots descending too deep, in which case the seldom produce flowers.
It blossoms in April or May, rarely produces seed with ease but is easily propagated by offsets from the roots, which can be taken up when the leaves decay, but should not be left long out of the ground."
This plant is useful.
How to get rid of:
Put on gloves and gently pull out the plant with the root system, you can use a shovel for convenience.