It was a very cold and long winter; you don’t need me to tell you that. We saw a prolonged stretch of subzero temperatures in January, didn’t have any frost until late November and stumbled through a cool February and early March. It wasn’t pretty for plants or people.
I knew that there was going to be some fallout from the temperatures but it’s really only now in late May after we’ve finally received some heat that the extent of the damage is becoming evident. So far we’ve seen issues with rhododendrons, lavender, shrub hibiscus, butterfly bush, trumpet vine, Oregon grape, Japanese holly and roses.
Broadleaf evergreens like rhodos and Oregon grape have brown foliage from a combination of bright sunshine and bitter cold in January; classic winter burn. I’ve noticed that the Oregon grape on the hillsides and elsewhere has begun to grow out of this. The ivy on the side of our building was similarly torched but is quickly recovering. Several plants of the columnar Japanese holly ‘Sky Pencil’ have died over the winter.
Deciduous plants like the butterfly bush and shrub hibiscus are, to be honest, rated at the edge of our hardiness zone. They will survive down to around -23 deg. C but if it gets colder than that or stays cold for a long period of time they succumb. If the cold doesn’t persist you might see new growth coming from the base of the plant once warm weather arrives. This has happened with a butterfly bush that I had. I was ready to dig it out when I noticed a small ‘smudge’ of green right at ground level. It recovered miraculously. If the cold gets too far into the ground as it did this winter the roots will also be killed. This has indeed happened in several instances, particularly with roses.
We stock plants that are rated hardy to Zone 6, which is the zone for Penticton and south within a few hundred feet of the lake level. Most winters it’s not an issue and even marginally hardy plants can survive if they’re located in a well-sheltered micro-climate type of spot. But we live in Canada and it does get cold, not every winter recently but it still happens.