Hardy and Nearly Hardy Passionflowers
There are a number of passionflower species that are hardy and in recent years some very smart breeding work has been carried out with polyploid hybrids principally by Myles Irvine, a now retired gym owner, who has dedicated a lot of his time to creating hybrids that have big, colourful flowers and are, above all, hardy. They have recently become available at mainstream nurseries and will, I’m sure, mark the start of a new era in passionflower cultivation in the UK and around the world. The hardiest are P. caerulea, P. ‘Snow Queen’, P ‘Betty Myles Young’, P ‘Damsel’s Delight’ and P x colvilii. If growing them outside dig a nice deep hole, use micorrhizal fungi, water with a whole can once a week for first season and protect with fleece first winter. If your plant is very small then grow on under cover and plant out in year two. These precautions should help the less hardy ones settle, and give the really hardies a great start.
Here you can see how much bigger P. ‘Damsel’s Delight’ is than P. caerulea
Passiflora x violacea. This cross first took place in Fulham in 1821 and has been repeated many times since so that there are a number of different cultivars going by this name. The form pictured is quite close to the original by Mr Sabine and Mr Milne, however the one you are most likely to get these days is P. x violacea ‘Victoria’ which is more free flowering but less striking and less hardy.
P. x violacea ‘Victoria’ and P. ‘Amethyst’ (see below) have been the best selling passionflowers in the UK after P. caerulea and P. caerulea ‘Constance Eliott’ for many years and deservedly so. They are bioth easy, borderline hardy and very free flowering. A great place to begin if you are starting a collection
Passiflora x kewensis ‘Amethyst’ (or just P. ‘Amethyst’ to its friends): This is a lovely coloured and free flowing hybrid (often confused with P. ‘Lavender Lady’ and frequently labelled amethystina, both of which are separate plants). It is hardy down to about -8 or so if allowed to get its roots deep in the first year and given a sheltered spot. The x kewensis is the result of recent research and it had to take the name from a very lovely hybrid now called ‘Kew Gardens’. The rules of plant naming are simple in principle but can be a tad confusing. Easiest perhaps to just refer to this as Passiflora ‘Amethyst’
Passiflora tucumanensis =n3 The =n3 part of the name indicates that it is triploid, having an extra set of chromosomes. I wil put a note about this in the tehnical notes section. This is a quite small flowered, pretty and lightly scented one. Allegedly hardy to -10 but I’ve not tested that yet.