I have a purple Datura that I grew from seed. Do you have any suggestions on how best to overwinter this plant? Basically I have found some contradictory information online but some of it suggests cutting down this year’s stalk (which seems a little drastic but I make no claims of being an expert). Any information you might have would be most appreciated.
Do you know for certain which genus and species your plant is? It sounds
like it could be Datura metel, which is grown as an annual. Datura
blossoms point up or outward, while Brugmansia is shrubby, and its flowers hang downward.
Some Brugmansias will overwinter in the Seattle area and are
semi-evergreen or evergreen. Others may die back to the ground and come
back in the spring. They are longer-lived than Datura. Datura is more
likely to act like a perennial or annual.
If you are growing an annual Datura, the best thing to do is save
seed from the fruit capsules in summer. Exceptions are Datura wrightii
and Datura inoxia, which can overwinter. In warmer winter climates, these
can be covered in the fall with twigs, straw, or pine needles. Growth may
resume in March or April. In colder winter climates, you would need to
overwinter the fleshy rhizomes in a container, covering them with earth.
Keep the container in a cool, dark garage or cellar. Expose the
rhizomes to temperatures of 53-64 degrees and daylight beginning in
March. This is much more difficult than simply planting new seed each
year, but plants which sprout from rhizomes grow faster and flower
better. (Source: Brugmansia and Datura by Ulrike and Hans-Georg
Preissel; Firefly Books, 2002)