Brooklyn Roof Garden Tilling the tar beach

In early June, our sempervivum — also called a houseleek or hen and chicks — seemed sleepy. We were told the sempervivium is excellent plant for a New York City roof garden — enduring the intense heat, the freezes and thaws of winter and the wind without complaint.

I realized last week that this plant was definitely up to something.

Now our sempervivium is blooming. I have to admit I almost threw this plant out this spring. I couldn’t really tell if it was alive or not. It was the pet rock our roof garden — just taking up space, space that I could use for flowers or something more showy. Now, after reading the sempervivums chapter in Joe Eck and Wayne Winterrowd’s excellent Our Life in Gardens, I am fascinated by our pot of “semps.” Turns out that these plants have a long history of growing on roofs. “In the ninth century, Charlemagne … issued an edict that sempervivums were to be established on every house roof,” says Our Life in Gardens (here’s a sample in Google Books).

I didn’t know why these plants were also called Houseleeks until I read Out Life in Gardens: “houseleek was also a pun, since the most decayed roofs of houses both supported the plants best and could be presumed to leak.” Leek, leak, get it?

“After flowering, the plant dies, usually leaving many offsets it has produced during its life,” says Wikipedia’s houseleek entry. With that in mind, I chopped off thee chicks. I’m trying to establish a new hen and chicks colony in the dry difficult conditions of the containers on our apartment buildings front stoop.