Wikipedia says Brugmansia needs moist, fertile, well-drained soil, in sun to part shade, and a frost-free climate. There are upland and lowland species. Most sold in stores are hybrids, but still fall into the upland/lowland temperature preferences. Here is another site with info and a forum.

Zone 8 is not frost-free. A healthy wrecked plant will regrow in warm weather. Brugmansia responds well to frequent light fertilization.

Brugmansia needs moist... soil? Or just does better so? I've seen them in dry, ignored-looking zone 10 yards. (And I've seen nasturtium blooming here in hot dry sand by a curb... but mine seem to want to stay moist... maybe I over-water?).

ekscrunchy lives within 10 miles of the ocean. Living near any large body of water modifies the climate, usually reducing extreme low and high temps. It's entirely possible that her zone 8 will most years have a zone 9 winter.

USDA took those factors into account in the assignment of hardiness zones. Apart from microclimates, any place that was assigned zone 8 is approximately same as all other zone 8 places.

Zone 9(as assigned)-like climate in zone 8 places results from planetary climate change.

Zone 9(as assigned) is not frost-free.

Yes, I am about 10 miles from ocean and as far as I know after spending about 7 winters here, there is never frost. But the flowers look so droopy!

Then either you are not in USDA zone 8, or you have a significant microclimate.

I live only a block from a very large body of salt water. The effect of that water mass is to moderate winter temperatures so that I am in a borderline zone 9 climate and can grow marginally hardy plants typically with ease. But neither zone 8 OR 9 is considered a frost free climate! While root hardy in zones 8 and 9, one can expect any brugmansia to die back to the ground seasonally if low winter temps are encountered.

btw, ALL brugmansia flowers hang down. That is just the nature of the plant. Upward facing flowers are found with the related but much smaller growing datura.

"Potting soil" purchased may be expensive but still may need some compost or finely ground wood and rotting leaves added.

Actually amending of planting hole backfill tends to create watering issues by producing a coarser texture within the hole than in the unmodified soil around the hole. Resulting in the soil around the hole having a greater attraction for water than the amended soil within the hole. So that there may be a recurring issue with the newly planted specimen drying out even with regular watering.

And if instead the planting site is naturally damp due to existing soil being heavy and retentive the opposite problem may occur during rainy conditions or with liberal watering. That is the amended hole acting as a sump, with water collecting within it and not draining away readily.

After any plants that survive generous amending of planting holes root into the more stable moisture conditions of the natural soil beyond the planting hole top growth typically picks up markedly, creating the mistaken impression that the amending was beneficial.

Agree about the differing textures. The other problem with ingredients that are not completely decomposed is that they usurp nitrogen for their decomposition.

Embothrium: very interesting! What, in simple directions, should one do to re-plant a 7-gallon potted plant into (probably) sandy soil of central/south Florida?

Embothrium, I see you have commented previously on GardenWeb about soil-amending before planting, but perhaps you were particularly concerned with planting trees. https://www.houzz.com/discussions/florida-gardening/query/florida-soil/nqrw

I like this comment from Pea in the above discussion (hey, do we hear from Pea any more?) on the question. "Amending the soil gives a new plant a boost to survive but in the long term that amendment is moot. But yes amend to get the babies going but don't count on your amendments to keep feeding in the longterm."

But I am open to correction.

It is pretty easy to verify that amending a planting hole for any type of permanent planting (anything other than shallow rooted annuals) is no longer an accepted or recommended practice. It is all over the internet from most reputable gardening sources. This now comes under the heading of a common gardening myth :-) It doesn't aid in establishment and can actually work to slow or impede proper establishment and restrict root development and healthy plant growth.

And it invariably impedes water percolation (aka soil interface) as water moves best through soil of uniform consistency.

I've heard that about amending the soil. I'm confused, though, should I just put new plants into the existing sandy soil with no amendments? Maybe some compost on top that will slowly make it's way down to the roots with the heavy rains?

If you must amend, do so over the largest possible area you can manage....like an entire planting bed, not individual plant holes. Otherwise, yes, top-dress or mulch with compost or whatever other amendment you prefer.

Keep in mind this is in FL - where gardening 'rules' for the rest of the country don't seem to apply very well. A lot of our soil can be little more than very fine sand that repels water when dry and offers little in the way of organic matter or nourishment for a lot of things that grow easily in more northern places.

And we are right now experiencing our dry season - very dry! I did not see where ekscrunchy filled the planting hole with water before planting, but that is often recommended. I do it once, wait for it to drain and do it again before placing the plant in the hole, then leave the hose set to a tiny trickle at the base of the plant for several days at least. Often, I have to work the soil in the planting hole to get the water to soak in. I believe the term is hydrophobic...?

Think not of rules, rather of concepts. The concept is that roots, hole, and ground beyond hole should have medium of similar drainage /retention characteristics. This does not exclude suitable amendment of medium, which is to be in all three places.

Not adding soil amendments applies to trees and shrubs. Trees (especially) and shrubs will send roots further than their canopies. The majority of roots for these are seldom deeper than 2 feet. Roots in heavy soils are even closer to the surface. A top dressing of compost, amendments, or fertilizer over an entire area (lawn, planting bed, etc.) is a better way to deal with fertility issues.

Most soil can become hydrophobic when it is very dry. Rain or irrigation will sit on the surface and only slowly soak in. For that matter, peat moss is hydrophobic. Plants in peat-based potting soil have to be immersed in water if they dry out. If watered with a hose, water runs around the outside of the soil ball and out the bottom of the container. The surface looks wet, but the interior is still dry. I make my own hanging baskets, adding Coco Peat to potting soil to make sure roots get wet when watered.