Photo of the leafy shoots of Leucaena. Leaves are bipinnately compound and heads of white flowers are borne in axils.

Leucaena leucocephala (#Fabaceae) has tremendous value as a forage & firewood crop in the dry tropics, but it has escaped wherever it’s been grown & is now a terrible weed. #Goodplantbadplant 📷: Forest and Kim Starr CCBY2 #Botany #PlantScience 🌾🧪

Close-up photo of a crowd of Salvinia shoots. Some water droplets are held in the folds of the leaves.

Salvinia molesta is a floating aquatic #fern. It's an ornamental pond/aquarium plant & a good candidate for biomass production (doubles in dry wt in as little as ~5 days!), but as an invasive species in lakes, it has caused immense harm. #Goodplantbadplant 📷: USFWS CCBYSA2 #Botany #PlantScience 🌾🧪

Photo of leafy shoots bearing clusters of yellow-to-orange lantana flowers and heads of metallic blue-black fruits.

Lantana (Latana camara) is a beautiful garden ornamental that feeds butterflies & is found in every "pollinator garden," but as an invasive species, it is a nightmare. It’s very aggressive & few creatures will eat it. #Goodplantbadplant #Verbenaceae #Botany #PlantScience 🌾🧪

Photo of a hand holding a plant of water hyacinth, in full flower and with dangling roots. In the background is a body of water covered by plants of water hyacinth.

Water hyacinth (Pontederia crassipes) has beautiful flowers & is food for endangered manatees, but as an invasive species, it smoothers lakes & waterways. Another big problem for my home state of FL. #Goodplantbadplant 📷: Florida Fish & Wildlife CCBYNCND2 #Pontederiaceae #Botany #PlantScience 🌾🧪

Photo of leafy shoots bearing terminal panicles of small red fruits.

Brazilian pepper (Schinus terebinthifolia) flowers attract pollinators, & fruits feed migratory & resident birds. It is, however, a horrific weed that invades & smoothers native plants in some parts of the world, like my home state of Florida. #Goodplantbadplant #Anacardiaceae #Botany 🌾🧪

Photo of a basket of dried coca leaves.

Coca (Erythroxylum coca) has been used as a stimulant for living & working at altitude, but addictive products like crack cocaine shatter lives & fuel organized crime. Illegal cultivation & processing cause environmental harm. #Goodplantbadplant 📷: Pierre Pouliquin CCBYNC2 #Botany #PlantScience 🌾🧪

Photo of flower buds, fruits and one open flower of poppy. POV is looking up to the flowers; tree tops and sky are in the background.

Opium poppy (Papaver somniferum) produces alkaloids that have relieved suffering for countless millions of people, but their addictive products have shattered lives & are a major profit center for organized crime. #Goodplantbadplant #Papaveraceae #Botany #PlantScience 🌾🧪

Aerial photo of oil palm plantation. Oil palm cultivation stretches for miles.

African oil palm (Elaeis guineensis) produces more oil per hectare than any other plant. It is a perennial tree crop, but plantations are wiping out fabulously biodiverse forests & causing untold environmental harm. #Goodplantbadplant : Ricky Martin/CIFOR CCBYNCND2

Watercolor diagnostic illustration of tobacco plant, showing flowers, leaves, flower dissection, and fruit.

No plant is intrinsically bad. In their relationship with humans, some have come to be judged as bad, but even “bad” plants have a good side. Nicotiana tabacum is a model organism for genetic & plant pathogen research, but tobacco use causes disease & death. #Goodplantbadplant #Botany 🌾🧪