Weeds of Wednesday: Hogweed

Oslo Riverfront Conservation Area, Treasure Shores Pak

Little hogweed (Portulaca oleracea) usually is regarded as a weed here in the United Sates, but this widespread, naturalized succulent of temperate and tropical places is cultivated elsewhere. Its species name, oleracea, means edible vegetable. Other common names include green purslane, garden purslane, common purslane, pusley, pursley, and wild portulaca.

Some sources say that this plant is non-native and originates from Africa. Dr. Richard Wunderlin, the University of South Florida botanist who is responsible for the Atlas of Florida Plants, believes this plant to be native, writing “Though sometimes considered non-native, the available evidence of its pre-Columbian presence in the Americas favors its classification as native. Among leaves, it has one of the richest known sources of a-linolenic acid, an omega-3 fatty acid.”

This plant is said to have been cultivated for more than 4,000 years for food and as a medicine. It contains significant amounts of vitamins A and C, as well as calcium, magnesium, potassium and antioxidants. Raw leaves are characterized as salty and peppery with a crispy, juicy texture. When cooked little hogweed becomes mucilaginous, so is used as a thickener (like cornstarch) for soups or stews. In Greece, the leaves are fried in olive oil and mixed with feta cheese, tomatoes, onion, garlic and oregano in a dish called panzanella.

Its appearance and its taste depend on environmental conditions. Plants in dry, sandy soils have a very prostrate growth habit, as above. Moist and fertile conditions produce plants that can grow to be about 6″ tall with thicker stems. Sometimes, the round stems are reddened.

Plants, we were told In grade school, were “factories” that “took in” carbon dioxide and sunlight to produce food via a special process called photosynthesis. In very dry and hot conditions, little hogweed conserves moisture with a special strategy, C4 photosynthesis. Little hogweed, when necessary, will open its stomata (pores) to “collect” carbon dioxide during the night, rather than during the drying day-time,  to reduce moisture loss and then convert it to malic acid, a sour-tasting substance. During the day, the plant converts the malic acid to glucose. Thus, little hogweed harvested in the morning tends taste tarter.

Its leaves are alternate sessile (attached directly to the stem), and quite fleshy, storing lots of water when available. Each flat green leaf is oval to spoon-shaped and broadest near the rounded tip, often with a reddish leaf margin.

Tiny, fairly inconspicuous yellow flowers held singly or in clusters in the leaf axils appear from mid-morning to early afternoon. Though hogweed is self-fertile (hermaphroditic), flies, small bees, beetles, and other small pollinators visit its flowers. Its tiny black seeds, which can remain viable in the soil for decades, are eaten by sparrows and other songbirds.

Hog food, people food, or weed depends on your point of view.