Most of them....

I think Joni at SRQ Hoyas has a list on her web site.

Thank you both, I'll search the srq site and start bringing in all the plants!

Thanks so much, I appreciate all the info. This is my first time overwintering Hoyas and I'm still learning tons everyday!

Here are a few more that can take 45F

I keep these outside year round in southern california, near the beach, doesn't get below 45F

austrailus tenuipes

serpens

obovata

kerri

fungii

cv Minibelle

Iris Marie

revolubillis

shepherdii

lanceolata bella

as well as some on the above list

This info was compiled from the David Liddle catalog:

Minimum Temperature

Something we will all find quite handy!!

Here is a compiled list of base temperature tolerances of some hoyas. This information is taken from Liddle's Nursery Catalogues of the past few years. It is a list of "base temperature tolerances"and is the lowest recommended tolerance. It should not to be taken as typical growing conditions.

C = Cool. Lowest temp. 50 deg. F.

I = Intermediate Lowest temp 60 deg. F

W = Warm Lowest temp 70deg.F

COOL

IML 6 australis ssp. australis 'Silver Valley' Qld.

IML 256 " " " 'Brookfield'

IML 46 bella

IML 1437 bella, albomarginate form

IML 201 calycina ssp. calycina

IML 51, 158,98,43,44 carnosas

IML 186 compacta 'Krinkle 8'

IML 444 fungii

IML 54 globulosa

IML 154 kerrii

IML 45 lacunosa var. pallidiflora

IML 377 lacunosa var. lacunose

IML 139 linearis

IML 185 longifolia

IML 149 motoskei

IML 50 motoskei

IML 269 obovata

IML 352 pauciflora

IML 148 polyneura

IML 87 pottsii 'sp. Chiang Mai' from Thailand

IML (all pubicalyx)

IML 59 serpens

IML 48 sheperdii

IML 461 HSI 037

IML 90 lanceolata

INTERMEDIATE

IML 1418 aldrichii

IML 24 anulata (as well as IML 84 and IML 1120)

IML 414 archboldiana (as well as IML 541, 560)

IML 217 arnottiana

IML 5 australis ssp. australis (as well as IML 7)

IML 1 australis ssp. tenuipes (as well as 565, 144)

IML 772 benquetensis

IML 224 bhutanica

IML 228 bilobata

IML 775 bordenii

IML 1216 brevialata

IML 724 burtoniae

IML 554 callistophylla

IML 418 camphorifolia

IML 372 caudata (as well as IML 965)

IML 189 cembra

IML 1352 chlorantha

IML 545 chlorantha var. tuituilensis

IML 1101 chuniana

IML 329 cinnamomifolia

IML 734 citrina

IML 716 coriacea

IML 1164 curtisii (as well as IML 1160 H.curtisii from Thailand)

IML 892 davidcummingii

IML 1185 deykei

IML 482 dimorpha

IML 71 diptera (also IML 261, 266)

IML 83 diversifolia

IML 337 dischorensis

IML 1377 dolicosparte

IML 298 eitapensis

IML 415 erythrina (as well as IML 511)

IML 713 erythrostemma (as well as IML 1428)

IML 1007 excavata

IML 391 finlaysonii

IML 118 and 423 flavida

IML 1278 greenii

IML 1116 halophilla IML 832 and 904 heuschkeliana (both the pink and the yellow forms)

IML 107 inconspicua

IML 187 incrassata

IML 1163 incurvula

IML 1054 ischnopus

IML 1580 kanyakumariana

IML 394 kentiana

IML 834 aff. kentiana

IML 92 limoniaca

IML 708 and 930 litoralis

IML 1161 lobbi

IML 987 loherii

IML 15, 16, 17, 220 and 449 macgillivrayi

IML 441, 1043, 1181 macrophylla

IML 152 magnifica

IML 735 meliflua and IML 124 meliflua ssp. Fraterna

IML 465 merrillii

IML 182 and 153 multiflora

IML 198 naumanii

IML 240 nummularoides

IML 234 and 1003 obscura

IML 1316 odettaea

IML 559 pachyclada

IML 421 padangensis

IML 97 parasitica

IML 454 parviflora

IML 391 pentaphlebia

IML 968 picta (syn. Pubera)

IML 161 polystachya

IML 18,20,22,37,39,86,353,489 pottsii

IML 728 purpureo-fusca

IML 78 pusilla

IML 1342 retusa

IML 1395 and 1424 rigida

IML 192 samoensis

IML 518 schneei

IML 1127 subglabra

IML 1177 thomsoni

IML 62 tsangii

IML 146,79,738 verticillata (ridleyi), verticillata (acuta) and verticillata

IML 452 vitellina (syn. Fuscomarginata)

IML 358 vitellinoides (syn. meredithii)

IML 100 sp. Aff. micrantha

IML 380 sp. Aff. chuniana currently in circulation as H. chuniana

IML 831 sp. Philippines - thought to be the same as H. sariae

WARM

All of the Eriostemma section of Hoya

IML 80 anulata (USDA354247 - flowers white with pink corona, leaf edges undulate.

IML 23 australis ssp. oramicola

IML 171 australis ssp. sanae

IML 1012 clemensiorum

IML 382 collina

IML 238 cominsii

IML 168 cumingiana

IML 955 dennisii

IML 1330 densifolia

IML 1155 hypolasia

IML 222 imperialis var. rauschii

IML 88 latifolia

IML 1098 megalaster

IML 768 mindorensis

IML 1575 mitrata

IML 559 pachyclada

IML 1096 and 1083 patella

IML 231 ruscifolia

IML 229 subcalva (BSI 1)

IML 1024 waymaniae

I live in S. Calif. and leave a LOT out in that olive tree and a bunch in a protected tend area on the south side of the house. However it rarely gets below the low 40s here and only for a few hours in the night for a couple of the winter months. The days shoot right back up into the 60s and 70 s usually. I have mostly the hardy species out there like carnosas and pubicalyx, but some that are listed as medium are out there too. We HAVE had a few freezes in past years where it went down into the low 30s for a few nights. Those times I went out and covered the biggest plants with burlap or towels pinned around them with clothes pins and brought in the a lot of smaller ones. I didn't lose any. Fortunately the weatherman was on top of predicting the cold snaps so enabled me to rush to save them. I had plants all over my floors for those nights. Ha ha these hoyas are pretty darned hardy I tell ya.

The more delicate ones I bring in & hang in front of the various windows around the house. I have installed rods above all of them for hanging plants. They hate it in the dry winter air, but they are hardy and survive as long as I get the watering schedules down.

I have a range of Hoya hanging in my covered patio. My min/max is at 43/115 with no cold damage on anything.

I have a bunch of Hoyas outside that experienced two nights of 37 F this past winter and they all survived. They're a little hardier than they're given credit for. The list includes: imperialis, coriacea, lacunosa, compacta, cagayanensis, dasyantha, subcalva, cv joy, macgillivrayi, serpens, epc 233, bintulu Borneo, calycina, shepherdii, mathilde, buotii, kanyakumariana, and hat som paen. Imperialis died back the worst, it looks like a 2 leaf cutting now and hasn't resumed growth. I won't leave it out again. Coriacea burnt up pretty bad and lost a lot of leaves but has resumed growth. Won't leave that one out again either. Macgillivrayi and joy had minimal dieback and have resumed growth nicely. Buotii dropped lots of leaves but is now about to bloom. Lacunosa looks rough around the edges but doesn't die back much if at all. All the other Hoyas seemed untouched. But this winter was one of the warmest on record :)

Can some of the cold hardy ones stay out doors if they are under cover? We get frosts, no snow. Lowest temps would be around -5 but that would be rare. I have a hanging pot of compacta on my front porch was well as a couple of pots of Krimson Queen and Krimson Princess and I don't really have room to bring them in. I currently have polyneura, Minibelle, KQ and one of my kerrii hanging inside in my hall way. Most of them were there last Winter so they will be fine there again this year I'm guessing. Instead of a heat mat, would putting a small heater in the plant room work for the Winter Wimps? Or do they need bottom heat?

Someone needs to tell some of my hoyas that it's getting cold, a lot of them are still actively growing!