Since their apparent re-invention in the 1990s, Penstemons have become one of the most popular of all summer garden plants. In Victorian times, after David Douglas had arrived back from the Americas, the 18 species that he returned with and the countless hybrids that resulted from them became a very popular summer garden plant.
There are around 250 species, mostly from the Western USA, and some of which are alpine but the vast majority of the species and the hundreds of hybrids are the familiar sub-shrubs, many of which are short-lived and require routine propagation in late summer to guarantee a healthy stock of young plants for the next summer. Many of us lost valued plants during this last winter and are probably still cursing ourselves for not taking a few cuttings last September. You have been warned.
The countless range of normal summer flowering hybrids require little else than removal of old flower spikes to help encourage some more and a little extra support for the taller ones that may get damaged in a summer storm. They do not require excessive amounts of food or water to perform well and, given a sunny, sheltered position, most hybrids will perform well for five or six years. Many will respond well to what is now known as the ‘Chelsea chop,’ to delay flowering until later if that is what you want. This means cutting the plants back in early June to encourage lots of new vegetative growth that will flower in August and September rather than late June.
Hybrids to search for this summer include Apple Blossom, Blueberry Fudge, Czar, Plum Jerkin, Raven, Snowstorm and Sour Grapes – ask at your local garden centre.
There are five National Collections for you to search out if you want to discuss Penstemons with experts. Visit www.nccpg.com for more details.