|I accidentally bought a package of Passiflora caerulea seeds from a local nursery being told they were the hardiest to grow this far north. According to my NAS fieldguide to wildflowers, there is a Passiflora incarnata that grows wild in Southwestern pennsylvania, when I contacted the company who makes the seeds. The told me to return the package I bought for the replacement of P.incarnata. According to the back of the package, it is zoned from 7-10. Is there another P.incarnata then that lives in comfort in Pennsylvania? Or is the package wrong? Would much appreciate an answer to what has become a 'mystery
of the hardy passionflower (zone 5)'.
|"The American Garden Book", written by the folks at the Brooklyn Botanic Garden, states that passiflora incarnata is hardy in zones 6 to 9. (Since parts of southwestern PA are zone 6, they may indeed thrive there. In fact, the plant is described as sometimes invasive.) However, I was not able to find a type that is rated as hardy to USDA zone 5. Passiflora caerulea is rated to USDA zones 7 to 10, and the reference states that often the stems are killed back to the roots in zones 7 and 8. Why not give P. incarnata a shot? Place it in a warm, protected spot and mulch it well in the fall, once the ground freezes.|