Plant of the Month

Plant of the Month: December 2019

Pellitory-of-the-Wall houseplant

Parietaria judaica L.

= Parietaria diffusa Merl. & Koch

= Parietaria ramiflora Moench

URTICACEÆ; Nettle Family

Those who grow many houseplants discover that weeds pop up routinely. A houseplant weed that I have lived with for a year or so, has proved itself worth this article.

Parietaria is a plant genus of 10 to 16 herbaceous species, annual or (usually) perennial, related to the familiar stinging nettles (Urtica species). Happily, Parietaria is devoid of stinging hairs. The best known species, Parietaria judaica L., is native in Europe and the Caucasus, but now a weed elsewhere. It endures sun but prefers shade, and is tolerant of --or fond of-- alkaline soil. It thrives in cities at the base of stone and concrete walls, and concrete curbs, hence its common name Pellitory-of-the-Wall.

No one grows Pellitory-of-the-Wall as an ornamental. It is small, devoid of winsome floral beauty or fragrance, and weedy. Its flowers are markedly tiny and dull looking; they are wind pollinated and some people are allergic to the pollen. The plant varies in the wild, but the version weedy in North America's West Coast cities has egg-shaped leaves on stems that are hairy. In sun, the stems are pink or red.

Over the years the most popular uses of this plant are medicinal. But in diverse places, especially in Italy, the young tender leaves are eaten, raw or cooked. After stems are harvested, the plant resprouts readily. The edible season is remarkably long --if your climate is mild, soil is fertile, kept moist, and shaded rather than blasted by sun. The young leafy shoots with or without budding flowers are edible, but the latter may contain higher protein content. The plants are excellent calcium sources. Regarding flavor, the leaves are utterly bland or weak cucumber-flavored; are certainly chewy, and mildly astringent.

My weed Pellitory-of-the-Wall houseplant, sprouted in a 3.5 inch pot of Æonium 'Pseudotabulæforme' (Green Platters). The window faces east. The plant has not flowered yet, possibly because I keep eating it [It eventually started flowering]. Its leaves are paler green and less glossy than specimens outside, possibly because it needs more nitrogen. The first 3 photos below were taken outside in Seattle; the 4th photo shows my weed with its Æonium plant. [The 5th picture, added in 2021, shows its flowers and seeds.]

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