Hi Adele - In my garden, both of these only work in deep gravel-ey soil beside my cactus collection. The hybrid penstemons do better than the species - even better than any southeast natives. All of them fade away after a few years (some in one year). The exception is 'Husker Red' and all of its relatives. I grow them in regular garden soil along with echinacea and shasta daisies but try not to water them as much. They come back year after year.

The only nierembergia I have had any sort of perennial success with is the one called 'Stary Eyes' (I think - I'm going on memory). Its white with purple/blue centers. Even it suffers during the damp parts of the year - like now. I still buy the solid purple one and just treat it like an annual.

Hi Adele, Glad you posted this subject. I got a Violet Dusk #1 on big discount and confused about siting it.
Your post and John's answer really helped.(at least I know not to consider it a long keeper so I know where to site it)

Adele, in further research I found that penstemon is considered a desirable forage for deer.

So that might confirm my spot putting it behind rosemary and lavender that the deer seem to leave alone.

Thanks John. That has been my experience with them too. Short live perennial, well drained rather dry and poor soil, at least for the species. That said my gardens have been at their prettiest when I have penstemon in them. I told my boss John that they are worth the four dollars even if you grow them as an annual. Never had much luck with nierembergia except when I lived in PGH. It bloomed all summer but was not perennial there, here for some reason I can't even get them to last long enough to flower. I have been told by more than one person that "Starry Eyes" is the best shot for a perennial one. I have planted ones that we start from seed for the past couple of years in late winter/early spring but they never survive long enough to flower

They are kind of important for the cottage or wildflower garden look. Nothing else does the tall skinny spire of flowers quite as well.

I have good luck sprouting Nieremberia seeds but my seedlings never get as full as what I can buy at a nursery so I quit sprouting them and just buy a few every year. The dark purple color is hard to find elsewhere.

I'd have to 2nd John on the Husker Red. I've had it in my cottage garden for about 5 years now. It has attractive foliage and blooms reminiscent of snapdragons. It is the only variety I would bother with.