Tender perennial requirements.

I will be overwintering some plants again in my summer house, which has reasonably good light. This year I have a heater and thermostat and plan to keep it frost free - but only just. It is too expensive to keep any warmer.

Is just frost free sufficient for :- Bacopa, Cuphea Ignea (cigar plant), Diascia, Heliotrope, Salvia patens, Salvia coccinea, Salvia splendens, Salvia Mystic Spires, Salvai guaranitica, Fuschia triphylla Korel and other non hardy Fuschias?

 

Hi PeterS,
Been having a google (anything but do the ironing!) found a couple of things for you.
Cuphea - should be ok, if frost damaged it should grow back.
Diascia should be ok frost free.
Heliotrope requires a minimum of 7 degrees C
Salvia patens - you can lift and pot up the dahlia like tubers to overwinter
salvia coccinea-hardy to -1C
salvia splendens- temperamental,needs warmer than frost free.
That's as far as I've got, hope it's some help. You've some lovely plants there, added a few to my 'wish list'

 

Thanks Windy - thats very useful - I feel guilty I should have been Googling these myself. Heliotrope appears to be the problem one. 7C is a difficult temperature, expensive for a greenhouse, but it may find inside a house too hot.

I wonder if anyone has any experience of heliotrope over winter. My books and even the internet sites are a bit ambiguous. One site says it needs 5C-7C over winter (as you said). It then continues:- under 5C it will stop growing and at -1C it will be killed. That does not make it clear what is an acceptable minimum - does it matter if it goes dormant.

I grew these from seed this year, and they were all very nice but perhaps my favorite is the pink and white Salvia coccinea. The Heliotrope took so long to grow that it has only recently reached a good size and is now flowering at its best.