All the penstemons in our modest collection have survived winter outdoors in various borders as expected.
Years ago, these perennial plants were seen as not reliably hardy and softwood stem cuttings were rooted in advance of winter, then stood with the minimum of watering, ticking-over in the cold greenhouse.
Although these modern cultivars are a breed apart, I continue this tradition in case the mother of all frosts visits and wipes out the border collection. When we’re safely past mid-April, the parent plants will be pruned to encourage new growth and the young plants will be found good homes.
Garden trade suppliers Ball Colegrave are the source of several stunning cultivars on sale at the garden centres. Their Sea series includes flowers in Coral, Purple and Red, each of which has a white throat. Blooms in the Volcano series are equally attractive and, if you enjoy name-dropping, it can’t get much better than pointing out Fujiyama, Etna, Kilimanjaro and Vesuvius to visitors!
Erysimum (perennial wallflower) is a fairly safe bet when it’s down to winter survival outdoors and our collection of five varieties has coped well so far.
However, they root so easily from stem cuttings that there is also back-up for them just in case.
Pride of place in the cold greenhouse goes to a collection of Dibley’s streptocarpus, which are tender perennials for potted indoor display. By withholding water, as you do with potted pelargoniums, and draping with fleece on cold nights, they’re surviving winter well.