Well Alicia this is yet another of my favorite topics. I live in the mid peninsula and before that lived in Berkeley. So, I have been lucky to be in some of milder areas of the SF Bay area. Thus, I grow many types of gesneriads outdoors all year. I do worry about one of those rare freezes though. It seems that many plants can take it down to 32 but start to suffer as it gets colder than that. Nematanthus seem to do well down to about 28-31 or so. The small leaved types seem to be the hardiest and can take mid to upper 20's. The big leaved kinds are a little more tender. Streps do fine down to 31 or so, but can defoliate and die if they are exposed to a long frost. Mitraria is quite hardy though, and it doesn't like indoor conditions. I grow it and its two close relatives outside all year long. Mousonnia is a cool grower that doesn't like to get frosted. So, it would be quite happy outside but you have to be careful it doesn't get hit by an overnight frost. I find that many sinningia species and larger type hybrids are quite hardy. But, the exposed tubers will get damaged if the temperature drops much below 32. In such cases the tops of the tubers get frozen and turn to mush but the buried portions will survive and usually resprout. So, if they are to endure cold snaps they may well need to have their tubers under some soil.

In my shade house I have most of my nematanthus, some hardy columneas (erythrophaea, schiediana, 'Sundowner' and one or two others, plus seedlings of 'Sundowner' x self. Aeschynanthus garrettii (quite hardy), gracilis and parasiticus, Codonanthe gracilis and serrulata. Chiritas of the rosulate type are generally hardy, though somebody has been eating them lately--so they are all indoors now, Lysionotis and other Chinese gesneriads are hardy though Primulina is tender. Achimenes are outside but they didn't like our cool summer.

One good idea is to cover your plants if there is a light frost. I have some frost cover cloth that I keep in the basement for this purpose. I have only used it once--about four years ago when we had a pretty bad overnight frost. It saved all the plants under it. Another great and obvious solution is to bring in those tender plants on those cold nights. I have at times covered the floors with flats of plants. Its a pain, but it does save things. So, you might keep your tender stuff together and in flats for quick trips indoors.

Jon

Many sinningia species and hybrids, especially the larger ones, are quite hardy. Most will take temperatures into the 30's with little damage, some will tolerate a light frost, and some with subterranean tubers, e.g., S. sellovii and S. tubiflora, are perennials that are hardy to zone 7b.

Titanotrichum oldhamii is also quite hardy, and overwinters with dormant underground rhizomes. It seems to be reliably hardy to zone 7b. Lysionotus and Raphiocarpus are fairly hardy, although they haven't really been tested--I would guess zone 8a, at least. R. petelotii still looks great in my garden, despite some cool days and cold nights (but no real frost yet!).

Some of the true gloxinias, Gloxinia nematanthodes and G. sylvatica, are also quite hardy. My G. sylvatica is still blooming and has been undeterred by nighttime temperatures in the 30s. Tonight will be the real test; we're supposed to get our first real frost, down to 29 degrees or colder.

Wow, thank you Jon and Johneib I really appreciate all the info, gives me a little room to work with as the greenhouse is getting full and I am not done pulling plants in for the winter. We often drop to the upper 20's with a few nights in the low 20's, I have found "pockets" in my yard that do not drop quite as low and have kept my Streps and other bordeline plants there in the past. I also have had a Rechsteineria leucotricha (I believe this is a gesneriad?) by my back door for 5 years and it never seems to suffer and flowers beautifully every year. ~Alicia

Alicia, your Rechsteineria is now Sinningia leucotricha. I have one by my front door. In the big feeze in 1990 I covered it and its large jardinaire with an old terrycloth bathrobe. I left the robe over it for two weeks, afraid to look. The exposed tubers were undamage despite getting to the as low as 18 degrees. I suspect being next to the house also helped. So, covering plants on cold nights is a good idea. People use old sheets and blankets but I bought a roll of frost cloth, which looks sort of like gauze, that I keep in the basement between freezes--its been about five years since the last one).

Jon PS I hope you can come to the gesneriad society meeting this month--third sunday of the month--so next weekend.

Ah-ha! For some reason I kept thinking that my plant by the back door was a Sinnigia - when I pulled the tag yesterday I was surprised to see Rechsteineria on it (how often do we look at our tags). Kind of threw me. I got this plant about 12 or 13 years ago without an I.D. so I must have found Rechsteineria I.D. somewhere along the way. I always have a collection of unamed plants that I am sorta/kinda looking for names of....like a scavenger hunt of sorts...
Jon, funny you should mention the gesneriad meeting - I was thinking about it this morning and wodering what time the meeting starts, 1:00 keeps coming to mind - is that right? I am hoping / planning on attending, I am looking forward to it.
~Alicia

Yes, Alicia we start at 1pm. Some people come earlier and have lunch. I am usually running around and getting there late.

BTW, my first Sinningia leucotricha came from a succulent mail order nursery as "Rechsteinaria leucotricha", in the mid 70's. Shortly after this genus was submerged into sinningia, a botanist found an herbarium sheet of another older species and thought these two were the same. So, from about the mid 70's until the late 80's we all thought the name should be "Sinningia canescens". You will find that name still on plants of leucotricha. But, then the true S. canescens was discovered at its original location in Brazil, and from live material it was obvious that it was a different species. so the final name (for the moment) is Sinningia leucotricha. I grow both of these species. My two oldest leucotrichas date from the mid 70's or older. There must be something like 60-80 species of sinningia and they are almost all in cultivation and available from the seed fund. I have a lot of them though not all of them.

Jon

Sorry to dig this thread up but...
I have what was originally Rechsteineria leucotrica bought as seeds by my mum from the RHS (royal hort soc). I had no idea you can grow it outside- is that what people are saying, or have you got it near your front doors indoors?
Also
Mine have the stalks with one round of leaves and flowers on. In some books they have tiers of flowers like the primulas. Is mine the same thing?
Also,
What is the diffference between Rechsteineria/sinningia leucotricha and Sinningia canescens?
Phew!
ps I find they grow so easily from seeds but usually just on the surface below the plant. I don't find them easy to pass on to others because they are soo brittle and I doubt whether they will bother to keep them through the dormant stage. I'd hate for them to be thrown away.

Wow, I did not realize gesneriads can take temperatures that low. I live in northern California. I also recently found out that streps can take it down to freezing if protected from frost, so I took my streps, nematanthus, columnea's out to the covered front porch that faces north west. They are doing much better since they have been out there. It is cold here at night, right now down to the low to mid 40's. Now I am wondering if I should take my chirita's out there. I have Chirita aiko, sinensis, Diane Marie, and Silver Surfer. If so, do I have to bring them back inside during the summer? It can get to over 100 degrees here in the summer. I know the streps don't like it that warm, but what about the chirita's?

Watch for frost. On a covered porch you may be OK on those cold nights. I would certainly get a max-min thermometer to keep track of the lows and highs. Be prepared to bring your plants inside if you get below 32. You can get some protection by covering the plants on borderline nights (29-33). But, there is nothing as safe as bringing them in for overnight protection. It is a hassle when one has hundreds or thousands of tender plants though ;(. I have been known to put my more tender plants that are outside, in flats or trays, for quick moves indoors.

Chiritas come from China. Most if not all of China is known to have frost. But, chiritas often come from the more tender locals with that country. So, they can usually tolerate cold but some are more tender than others. C. speciosa is native to Hong Kong, and thus is more tender. I would give that one more protection. The others would be hardier. C. 'Diane Marie' has speciosa as one parent, but the other parent, fimbrisepala, is one of the hardier species, so should be OK. I have overwintered speciosa outdoors in mild years but I am in a mild climate on the San Francisco peninsula.

Chiritas should be able to handle heat as well. I suspect they come from places with hot humid summers, though some are mountain species and may prefer it indoors. Try some experiments to see where they grow best for you. Meanwhile, take some leaves to root. They propagate very easily from leaves, and from your propagtions you can experiment with various growing conditions. If you are near Sacramento, there is an excellent local chapter of AGGS, the Delta Gesneriad and African Violet Society.

Jon

Jon, I think you mean C. sinensis, not C. speciosa.

Ugh, I am losing it. Yes, I am getting those two confused. I will repeat sinensis to myself a hundred times to get it back in my brain. Thanks for the correction.

Jon

I have alsobia dianthiflora that I keep in an unheated enclosed porch in winter. The temp goes as low as 40 and it doesn't seem to mind at all.

Petrocosmea species can take temperatures to 45 degrees F.

Nancy