Nicotiana glauca aka Tobacco Bush

Nicotiana glauca, or tree tobacco, belongs to the nightshade family. Its native range spans Bolivia, southern Brazil, and southern South America. It grows as a loose shrub or small tree. Most garden plants reach about 9–10 feet [2.7–3 metres] tall. Their spread reaches about 9 feet [2.7 metres]. Some plants reach 20–22 feet [6–6.7 metres]. It grows fast and forms many thin, upright stems. Young stems are smooth, hairless, and partly woody.

The blue-green leaves give this plant much of its appeal. Each leaf has a stalk and grows alternately along the stem. The leaves are simple, oval, and smooth along their edges. They feel fleshy and have a thick, waxy coat. Large leaves reach 0.67 feet [0.2 metres] in length. Plants may keep some or all their leaves through winter. Leaf loss varies with growing conditions and the source account.

Clusters of tube-shaped flowers grow at the ends of stems. Their shades range from cream to yellow and yellow-green. Each flower has five lobes at its open end. NC State lists spring and summer bloom, with flowering from June onward. Moths and butterflies visit and pollinate the flowers. Egg-shaped capsules follow, each with two valves and many tiny seeds. Wind and water carry these seeds away from the plant. The yellow flowers stand out against the cool leaf colour.

Tree tobacco grows best in full sun and moist, well-drained soil. It also tolerates part shade and periods of drought. It accepts sandy, loamy, or clay soils across a broad pH range. Rich, deep soil suits it well. NC State lists USDA zones 7–10, but warns of frost damage. Brief cold spells near 23°F [−5°C] may be tolerated. Hard winters can kill it. In mild British gardens, it may die back and regrow. It spreads along roads, riverbanks, rocks, and walls outside its native range.

Its main landscape drawbacks are poison risk and invasive spread. Dense stands can crowd out native plants, including in California. Sources record medicinal use and extraction for insecticides, not safe home treatments. Leaves have also gone into drinks, but ingestion is unsafe. Every part is poisonous to people and livestock. Dogs, cats, and horses are also at risk. Eating it can cause vomiting, paralysis, breathing failure, and death. NC State lists no known pests in its care notes. The same page also links southern bacterial wilt as a disease concern.