Penstemons - the long-lasting star of the show

Amid the emerging crackle and tangle of my fading autumnal garden, there are still a few plants that have retained their vigour and even blooms. While it’s hard to tear my eyes away from the delightful soft fans of the grasses (Miscanthus sinensis ‘Morning Light’ and Calamagrostis brachytricha) that have risen to the occasion of the season, kudos must be given to the gaura (Oenothora lindheimeri) which has only just started to lose its fluttering little petals, having held court in the garden since early December. At the height of summer, it overwhelmed all its neighbours and I planned to pull back its presence for next year, but I’m now having second thoughts given the softness and sparkle it has bought in the glowing autumn light as everyone else has started to decline.

Penstemon ‘Garnet’ amid late seasons gaura.

However, it’s really the penstemons that haven’t got their perennial memo to pack up shop, even after our first proper frost here in Christchurch last week. My white-belled Penstemon ‘Snow Storm’ plants have flourished since mid-spring, and I feel if given the chance, they would simply push on through with no end!
The beautiful, taller crimson variety of Penstemon ‘Garnet’- growing to about 90cm with plum-coloured stems, was a late addition to the beds in early summer and they have simply bolstered themselves continually, even now producing their jewel-toned, budded spires. I chose this variety on the recommendation of its romantic open form and I have most certainly been rewarded.

My penstemons and their gusto aren’t unusual however, with many of the genera’s 270 species and 800 cultivars and hybrids having an evergreen or semi-evergreen presence. Nearly all penstemon species hail from North America where they are broadly referred to as ‘beardtongue’ and can be separated into ‘border’ and ‘species’ groups.
The former are the most commonly found varieties growing to between 60 – 80 cm with the longest flowering period. The species penstemons tend to be lower-growing with smaller flowers and a shorter flowering period but offer sometimes special and intriguing interest!

Penstemon ‘Snow Storm’

Most penstemons hallmark flowering spires have a trumpet form similar to foxgloves however they bloom profusely from bushy clumps. With the availability of compact dwarf varieties through to airier, taller growing ones, I believe there is a penstemon for every gardener’s unique style!

They seem to be outrageously hardy and my longer-kept plants that have just moved through their fourth growing season are showing little indication that they are tiring.
During summer I do deadhead when I see the opportunity to encourage their performance, but in all honesty, in being lax on this job over autumn, I notice that they push on despite me. They are also the perfect candidate for taking cuttings and offer great potential for multiplying your stock as you please.

I find their form and hardiness extremely enticing despite never being all that keen on the tangerine models that grew in my mum’s garden or, perhaps controversially, the varieties with white throats. What absolutely can be agreed on is that the available rainbow of colour choices and their attractive spires bring great dimension to any mixed planting. Colour, combined with their long flowering season provides an exciting tool to dictate the tone and flavour you desire in a garden bed.

Penstemon ‘Snow Storm’ amid Verbena bonariensis, Phlomis russeliana, echinacea and coreopsis verticillata ‘Moonbeam’.

I particularly have enjoyed the combination of my earlier flowering ‘Snow Storm’ variety bringing its frill to the straight-pronged stems of echinacea and as a crisp contrast to my mid-spring run of aquilegia and phlomis. The ‘Garnet’ looked fantastical in support of its airier dotty neighbours of knautia and gaura.

But, like all gardeners, I have a bit of a wish list on the go which includes the outrageously saturated and aptly named ‘Electric Blue’, and ‘Husker Red’ which sports burgundy foliage and stems with cream bells. I’ve been inspired by the drifts of ‘Blackbird’ in public planting in Christchurch, creating beautiful deep plum accents paired with pink gaura. And with some online digging, I’ve trained my eyes to look out for the availability of Penstemon whippleanus ‘Chocolate Drop’ that sports clusters of deep purple, almost black, trumpets.
 

And lastly, a quick note of appreciation to the readers that have reached out to me over the last three years. This column has propelled my knowledge forward to no end, forcing me to uncover and present concepts, gardens and plants in a way that both you and I can actually understand!

After 90 articles for Stuff I’ve decided to follow the urge of creating and curating richer garden-based content on a larger scale. I want to share more New Zealand gardens in greater detail, offering a place where I can spotlight my favourite garden voices and connect us here in Aotearoa with gardeners and their spaces from further afield.

Watch this space - all will be revealed next week!
Ju xoxo