Minimum temperature for tropical amaryllids?

Lee Poulsen
Thu, 23 Apr 2015 23:57:30 PDT
I agree with Diana. Hippeastrums aulicum and papilio won't be bothered by anything above 32°F. I leave those out all winter long and they never have any problems. Some of the others only have trouble with cold temperatures in the 30s and low 40s if it stays that way for days on end without ever getting warm while sitting in moist or wet soil. So I keep them dry and protected from our winter rains (when we get them!) and they're fine outside against the side of my house. If your weather is expected to go back to a warmer temperature range next week, you have nothing to worry about. The Eucrosias and Clinanthuses also aren't bothered by the occasional drop into the 30s. They are nothing like the true warm tropicals that start to look like they've been frosted once the nights drop below the mid-40s consistently every night and die soon thereafter. I have to bring those inside once winter truly hits here in So. Calif. Luckily I don't have many of that type of plant. (All temperature references are in Fahrenheit. My apologies to the rest of the world.)

--Lee Poulsen
Pasadena, California, USA - USDA Zone 10a
Latitude 34°N, Altitude 1150 ft/350 m

On Apr 23, 2015, at 12:56 PM, Diana Chapman <> wrote:

> I have heated benches for some Brazilian species, but don't have enough room for all, so most go on to the regular benches when they are past the seedling stage. My greenhouses go down to near freezing in the winter, but not for long, no sustained cold temperatures.  I have only lost a few to cold.  They normally go down to the 40's here at night.  I would just cover up your more tender species.
> Diana
> Telos
>> For the past couple of weeks, I have been moving my potted plants from the
>> greenhouse to the outdoor benches where they spend the summer.  I usually
>> wait until night temperatures are reliably in the 50s, but the forecast for
>> tonight is 39 F (4 C) followed by several nights in the upper 40s (~9 C).
>> Days will be in the mid 60s.  I'm worried that this might be too cold for
>> tropical amaryllids, particularly if we get rain on Saturday.  The plants
>> include Eucrosia and Clinanthus species, assorted Brazilian Hippeastrums
>> (H. aulicum, H. calyptratum, H. papilio, etc), and several Cyrtanthus
>> species.
>> I don't really have a feel for how cold sensitive these plants are.  Should
>> I haul them back into the heated greenhouse for a couple of days (a
>> significant amount of work), or am I worrying unecessarily?
>> Nick Plummer
>> Durham, NC, Zone 7

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