Q: We have some white, pink and yellow brugmansias established from donated cuttings. We have had limited success with maintaining good vigor of some of the plants during the growing season. Do they do better if re-propagated annually from cuttings, or should they be sufficiently cold hardy in the Raleigh area to overwinter OK?
We usually heavily mulch the root system after cutting them back in the fall. This year a severe early frost pretty much destroyed several plants that were just about to bloom - the cold even ruined the stems, so we could not salvage any cuttings.
We would appreciate any insight into handling these beautiful plants. - Allan and Judy Nicholas, Wake Forest
Some brugmansias (known as angels' trumpets) are hardy outdoors up to our Zone 7b, so even though your pretties were nailed above ground by that killing, freezing frost, don't be so quick to dig the "dead" plants up, because the roots may have survived.
Being at their northern limit, like many perennials, garden-planted brugs will die back here in winter but usually come back in spring. However, two factors will prevent this spring rebirth. First, if we have a nasty, extended Canadian kind of winter (it has happened), the cold will penetrate the ground far enough to kill the plant's roots. A cozy winter mulch will help prevent a deep freeze death, but only if the soil around the plants is well-draining. Mulch retains moisture, so adding this organic covering in winter to an area that puddles will create a wet, cold, very unfriendly environment for tender roots - and this might be why your plants don't do so well during growing season.
Second, not all brugmansias are created equal, especially when it comes to cold hardiness. Your brugs, which have hung around the last few years, are probably hardy. The salmon pink 'Cherub', yellowish-orange 'Charles Grimaldi', beautifully, ghostly pale 'Double White' and apricot-colored 'Sunset' are cold-resistant selections that can also do well in our region. Check with your local garden center for additional hardy cultivars.
As a Plan B, because you are into brugmaisia propagation, consider starting a few cuttings in containers and let them overwinter indoors. Because these plants can get rather large - 8 feet plus in height - you will need correspondingly big containers and a strong back to lug them outside in the spring and back inside in the early fall. Dwarf varieties require smaller pots and less effort to move around. 'Inca Sun' and 'Angel's Summer Dream' are two shorties that come to mind.
And don't be so quick to cut down your plants after the frosts have nipped them. I have had better results pruning the dead, hollow stems back in the early spring after the worst of the cold.