Yucca Do has the largest commercial list I've seen--that is, with hardiness ratings--and there has been quite a bit of discussion about this on the gesneriphiles list. Lots of sinningias besides S. tubiflora, some Gesnerias that might be hardy for you tho' not for most of the country, Hemiboea henryi if I have its latest name right (no guarantees!), I think Aeschynanthus garettii, some Nematanthus--tho' we theoretically live in the same zone I'm familiar enough with California to know your climate is seriously different. If you can get over to San Francisco to meetings of the gesneriad society there you could get a lot more information. Jon will probably be along any minute to tell you more.

Oh my ears are burning again. Yesterday was the gesneriad meeding at the park. We didn't get our slides for our formal program so we did an extended show and tell. I as asked to bring in as much as I could, and I took the request to heart and filled my station wagon with plants. I even brought in two impatiens. So, you would have felt right at home at our meeting. Most of the plants I brought in I grow outdoors all year too. But, my peninsula conditions are very different from Sacramento. So, I am not sure of what I have that would be hardy for you. Soem aeschynanthus like garrettii, also in mild years many others, such as gracilis, parasiticus etc. Nematanthus are all quite tolerant down to 32 and some take it down to the mid 20's. Probably australis is the hardiest--it is the southernmost in habitat. N. fornix (nervosus) is a high elevation species that may resent your heat but would be hardy. The common hybrids are fairly hardy too, as they are mainly combinations of somewhat hardy species like gregarius, fornix, and wettsteinii. Hemiboea henryi is now H. subcapitata--it is a hardy deciduous perennial. It and many of the Chinese gesneriads would be fairly to completely hardy. They like warm humid summers and cool dry winters--the rosulate chiritas, petrocosmeas, hemiboaea, and a few others. Also, the genus lysionotis, which is related to aeschynanthus but has flowers more like a streptocarpus. They are perennials for a moist shady spot and do very well in large pots. The best one is montanus, which flowers heavily in mid to late summer. Another, that has beautiful foliage is ikadae, native to a tiny island between Taiwan and the mainland. Streptocarpus like cooler condiditons than the valley, but take it down to about 30. A few columneas do well down to about the same temps--schiediana and erythrophaea, both from highland Mexico.

On Gesneriphiles we recently has some posts from Vincent Parsons who reported on what survived in his unheated greenhouse in the Portland area. I was amazed at how much came through in his enclosed but cold structure where it got down into the 20's.

Jon

There are plenty of gesneriads that should be hardy in zone 9, including many (I would venture to say most) Sinningia species, but especially the taller ones with subterranean tubers (like S. tubiflora). Check out the link below for a discussion of hardy gesneriads.

I currently have Titanotrichum oldhamii, Raphiocarpus petelotii, Sinningia sellovii 'Purple Rain', and an F2 seedling of the hybrid S. sellovii x S. tubiflora sprouting after a fairly cold zone 7 winter. Several Achimenes and Gloxinia species and hybrids are also supposed to be fairly hardy, but I haven't had any luck with either of these genera overwintering so far.

Here is a link that might be useful: Cold hardiness of some gesneriads

This is Vincent in Portland, Oregon, sitting at my desk at work, while the convention is going on only a few blocks away :(
I did get to go out with eveyone to the local gardens tours yesterday, which was nice.

LOL Jon, that should be "partially enclosed"- I didn't even bother to close the door to the greenhouse all winter, because cats and raccoons had already torn out a big section of a wall, and the heater had been doused by a leak, so it wasn't even plugged in all winter. The plants had some shelter from the rains and snows, but that's about it. Temperatures dipped into the upper 20s F a few times, and went to below freezing many times over winter. Our weather is of course colder than Sac., anything that can take the cold of winter and heat of summer in a greenhouse here should be hardy there.

Here are exerpts from what I posted on gesneriphiles recently about the survivors outdoors. There are a few more not listed there, like Aeschynanthus 'Red Elf', which started blooming in the open 'greenhouse' in early spring in still-cold weather. Also Gloxinia 'Odyssey', which is resprouting, and there are lots of healthy looking undamaged rhizomes in there.

The Smithianthas that didn't dry to a crisp last winter, and them mold when I watered, are thinking about growing. They always start late anyway. Unfortunately most of the Smith's tags were dumped out by animals and only a few will ever be labeled with certainty again. It wouldn't surprise me to see Smithiantha survive, at least some species and hybrids that are descended from plants from higher parts of Mexico & Central America with cold nights.

===============================================
Posted May 12, 2005:

"...we have very dry, low-humidity summers. Dry sun
still didn't bother S. sellovii at all, and S. tubiflora
only a little, from what I saw last year.

Growing now after being in the ground since last
Spring:

Sinningia tubiflora (Full sun and loved it)
S. sellovii (Full sun and loved it)
S. "black hill" (Part-sun, about 8-9 am to noon-ish)

It's too early to tell about the S. schiffneri 'red
leaf'. It's near the "black hill" but I don't want to
dig around it yet. Those are the only 4 I had planted
outside in exposed ground.

Hands-down winner for hardiness here is the Sinn.
known as "black hill", formerly a.k.a. "aff. reitzii"
I think? The plant under cover in the open-air
greenhouse continued blooming all winter, right
through the freezes, until I cut it back recently
because it was leggy. (S. glazioviana did the same
thing, but I hadn't planted it in the ground. I will
this year.) The "black hill" in the ground died back
almost to the ground in December or January, but a few
inches of stem aboveground are re-sprouting. It's
doing the running-tuber thing, too: It was put out
last spring near an East wall in part-shade. Now
there are sprouts 6-8" from the original stem coming
up. I accidentally pulled a couple of those with
weeds, before I realized it had spread!"

[S. tubiflora also spread a lot, and sticking a spade under it was like lifting a pile of miniature potatoes! I even sliced a few in half that were further from the center than I expected]

=======================================================
Posted May 15, 2005:

"As promised earlier, here's a list of most of what
survived the neglected, unheated, and rarely watered
greenhouse, open to the outside air at all times.
Min/Max thermometer said lowest temp was 27 degrees F;
there were many freezing nights over a few months, I
didn't count how many or how long.

Everything marked "***" is being propagated for
convention, and more that's not listed here! Not a
great many of each though, usually 2 to 10, so don't
leave yours at home if you're propagating the same
ones.

Species/cv. Result/Damage

Chirita tamiana
Medium. Discolored leaves, flower bud blast. Quick
recovery. Ironically the bowl of 9 plants indoors died
of neglect. [now blooming again]

*** Chirita USBRG 98-083
Light or none. Some older leaves limp (Possibly too
dry)

*** Chirita gemella
Light or none. Some older leaves limp (Possibly too
dry)

Chirita 'Kazu'
Heavy. Leaf loss, slow recovery. Weak/attracted
insects. [now in bud again]

Chirita sinensis
Light or none. Some older leaves limp (Possibly too
dry) [now blooming again]

Chirita 'Aiko'
None. Held all flower buds & leaves despite dryness.
Leaves turned partly purple but are all green again
now. [now blooming again]

Petrocosmea flaccida
Light or none. Dormancy as small tight crown. Locals
have been keeping these outside with only overhead
protection for years.

Petrocosmea 'Momo'
Light or none. Dormancy as small tight crown.

Primulina tabacum
None, partial dormancy, some bud blast. [now blooming again]

Hemiboea subcapitata
None, of course. Went dormant.

Nematanthus (all)
Light to Medium. Leaf loss, some branch loss, but
quick recovery if not dried out completely for too
long. All of mine are gregarius/wettsteinii types,
plus 'Stoplight' and ***'Black Magic'.
***Codonanthe gracilis
Light to medium, as with Nematanthus.

Codonanthe devosiana 'Paula'
Medium, some lost. Probably too dry.

***xCodonatanthus'Tambourine'
None, continued light bloom all winter

***xCodonatanthus 'Sunset'
None.

Aeschynanthus speciosus
Light or none.

***Aeschynanthus 'Rigel'
Light or none.

***Aeshcynanthus 'Big Apple'
Light or none.

[add: Aeschynanthus 'Red Elf'
-No damage, resumed bloom in early Spring]

***Lysionotus serratus
None. Flowered through some freezes. This is a
beautiful and sturdy plant, if a little ungainly when
unpruned. I love it.

***Lysionotus pauciflorus
None. Flowered through some freezes. Also appears to
have set seed- but pods were open and empty when I
noticed them. [now blooming again]
***Raphiocarpus petelotii
Light or none- some stems went dormant to soil level.
Early recovery. Already known to be hardy.

Sinningias are not considered damaged if they tops
died back, but the tuber survived undamaged and
recovered well. Nealy all grown with tuber exposed.

Sinningia (various minis)
Medium. Went dormant to tuber, some were lost.
Surprisingly, about 3/4 of these are growing again.

Sinningia 'Carnaval'
Heavy, died back to below ground, but thickened stem
part (almost a tuber) is still alive.

Sinningia 'Apricot Boquet'
None. Went dormant. [now growing fast]

Sinningia lineata
None. Went dormant. [now blooming again]

Sinningia brasiliensis? x(?)
None. Went dormant.

Sinningia "black hill"
None. Bloomed through freezes, until cut back.

Sinningia glazioviana
None. Bloomed through freezes, still blooming. Hoping
for seed. One tuber is sending up many sprouts, will
root them for convention as soon as tall enough.

***Sinningia cardinalis x leucotricha
None. Went dormant. Young sprouts look like they
might take root.

Sinningia (cardinalis x leucotricha) x leopoldii
None. Did not die back. setting flower buds now.
Could be "Black Hill" rather than leopoldii, tags lost
due to animal activity. Will know soon.

Sinningia leucotricha
None. Did not even die back, but flower buds blasted. [now in bud again]

Sinningia 'Georgia Sunset' x self F3 various colors.
None. Went dormant. [now blooming again]

Sinningia speciosa (wild type from seed mix)
None. Went dormant. --S. speciosa 'Sao Conrado' died
though, Waaaaah :(

S. tubiflora, S. sellovii
None of course. Went dormant. Lived over in flower
beds unprotected. Already known to be hardy.

S. schiffneri 'red leaf'
Medium. Died back to below ground, surviving parts
slow to recover. Same story in ground, unprotected.
Cutworms got this one too, should re-grow.

S. ibitioca:
Commenting even though dead- kept its foliage green
late, like the other hardier ones, but then ended up
under a drip where they rotted out. I'll try again
when I can get more. All 3 of my ibitioca were still
in one "temporary" pot together- dumb mistake!

S. calcaria:
Deceased- but same story as S. ibiotica above.

Scaly Rhizomes:
Too early to tell in most cases. Can't find rhizomes
in any Phinaea, Niphaea, or Diastema pots. Some
various Kohleria, Smithiantha were healthy looking but
started to mold when it warmed up a little. No
noticeable rhizomes in some Achimenes pots (including
the hardy 'Purple King'!) - but A. misera SI 88-039 is
full of fat, healthy ones. xGlokohleria 'Scarlet
Letter' and xSmithocodonia 'Dave's Tree' have some
live rhizomes resprouting.

There were of course many more gesneriads than that in
there, but I did lose a lot of them, and there are
many others I haven't checked closely yet- there may
be more dormant survivors. I don't know if I'll make
a list of what froze out- too depressing!

On the bright side, most of the cacti (no surprise)
and other succulents (some surprise) were fine. The
ones that died were under broken roof where they got
rained (and snowed) on. Some other tropicals surprised
me too, but I did lose my favorite Hibiscus and about
half the Hoyas. Oleanders I got while at the AGGS
Convention in Sacramento (Hey, did I mention there's a
Convention here in Portland this year?) are already
beginning to bloom, even though I discovered that they
had been getting poured on and soaked for a good part
of the winter too.
============================================================

Vincent

Wow...just dug up this thread. Interesting! Since it is time to start autumn clean up and think of what to bring in & what can handle staying out, I find it a good idea to refresh memory on this.
You had mentioned that about "half" your hoyas didn't make it. Would you let me know which ones DID survive? I have mostly hoyas out under my tree now. However it doesn't usually freeze here, but I would be interested in knowing which ones could take it. Also, how cold did it get where you are talking about there? Thanks.
Marcy

I am digging this old thread up because I'm getting back to growing some more gesneriads after some years of only having a very few, and want to continue tracking hardiness. I can add that the S. [cardinalis x leucotricha] x leopoldii was in fact what I thought it was, and has survived quite a few years of winter freezing, but always under cover to keep it on the dry side.

Marcy, if you're still around, I apologize for missing your post... I will try to think about what Hoyas made it, but sadly my memory has faded quite a lot from that time. I wish I had listed those somewhere!

The Chilean Mitraria and Sarmienta are also hardy.