Celene,
They absolutely need protection from freezing during their dormant period. After they have dried out, I cut off the dried foliage for storage where they won't freeze during winter. They still take up space. I store some in cardboard boxes which I put in a storeroom that's in the garage. Others hang from a rod I've fixed in the same storeroom. I had some hanging from the ceiling in the garage last winter and others I had hanging from cup hooks screwed into the enclosed porch wall. None of those places are heated, but I could raise the temp in them if I absolutely needed to do that. As it is, the coldest air temps usually stays above freezing and probably 35-36F for a short period is the low temp. They are dry and still in the soil. They are probably in more danger of desiccation and mice than freezing. In the past, there have been some I didn't get inside that got caught in a hard freeze. Those didn't survive. But during storage there is no worry about light or whether they need water. They just sleep until I decide to start waking them up or they start sprouting on their own. Normally it's me, but all those places can get warm during our winter warm spells. They seem to require a rest period and some sleep longer than others. It's my understanding that all the new rhizomes are maturing as the visible plant withers after it has finished blooming for the season. Here are some photos I just went and took. The first is Achimenes 'Yellow Beauty'. I haven't actually quit giving it water yet, but as it has gone dormant I slacked off. It's ready for the foliage to be trimmed off and the container, soil and all, put in storage.
This next one is XAchicodonia 'Shogun'. Not quite completely dried up yet, but enough I could cut it all off for storage.
Then there's XAchimenantha 'Inferno'. It hasn't reached peak bloom yet. This would be my favorite if it was earlier. I took the second photo earlier this week. I'm sure 'Inferno' was given it's name due to the intense red blooms, but it could have just as easily been named that for the way the light turns the plant red when it's backlit. I didn't begin to capture how fiery the foliage was with the late afternoon light shining through the foliage. That is a trait nearly all the Achimenes have, though the colors range from bright pink through orange and purple, depending on what is the predominant color on the back of the leaves.
