We will be up at an ungodly hour on Monday morning to catch a plane for a fortnight’s retreat to Greece. It is the time we prefer to go away. When the harvest is mostly in, and we can leave the garden to relax into autumn. There will be a push over the weekend to harvest seed that will have dropped by the time we return and to pick the pears and the apples that will become windfalls if we don’t. But it will be important in the flurry to put a moment or two aside to look at what we are about to miss. At the first perfectly formed goblets of the Colchicum autumnale and the gold of the Sternbergia lutea that have just begun their season.
Though for years now we have made this our time to be away, I have always planned for continuity. For the relay of the new and the succession of interest that can run the duration of the growing season. As we leave, the first asters are already waning, pulled down by the rain or simply having had their day but it is good to know that the late forms, which are still in bud and standing tall, will have the energy in them yet to claim October.
The ironweeds are as steadfast as the asters and as worth making the space for, for the energy they bring as the garden wanes. The first into flower in mid-September is Vernonia arkansana ‘Mammuth’ (main image). Standing as tall but more broadly than me and offering up a well-furnished dome of vibrant violet flower, they are what currently draws your eye. The colour picks up on that of two asters, the mid-season Symphiotrichum novae-angliae ‘Violetta’ and the later-flowering Aster ageratoides ‘Ezo Murasaki’, which is just starting to flower. Known as ironweed for the rusty tones of their light-catching seedheads and stout winter presence, they will be good for a while yet and provide strong skeletons right through the winter.
I do not quite remember where I met my first vernonia, but I have a feeling it was on an autumnal trip I made in the early ‘90’s to look at perennials in Holland and Germany. It may well have been at Mien Ruys’ garden in Holland or the grounds of Karl Foerster’s house in Potsdam, where a whole generation before us had been using these powerful prairie dwellers. Giants such as eupatorium and Rudbeckia laciniata ‘Herbstsonne’. Perennials that you have to make room for in a planting as you might a shrub then stand back and admire.
I had never had the room for vernonia until we came to Hillside, but I am happy now that I didn’t hesitate to include them once I had the space. ‘Mammuth’ has been a fine presence, slowly building into a reliable clump and promising to be a long-lived perennial that will go years without the need for division. In the wild, ironweeds are tolerant of a wide range of conditions, being adaptable to clay, rocky and gravelly soils, alkaline pH, drought and temporary inundation of water. A range of conditions that might suggest they are the kind of plants we are going to need in a climate that is not only changing, but showing that change here in the UK in unpredictability.
Even in the last ten years of gardening here, the plants have been the litmus of change. The cimicifuga and phlox that were possible a decade ago can no longer tolerate the heatwaves and some salvias have failed after months of winter deluge. All the vernonia here have sailed through where the eupatorium have demanded summer water and the Achillea millefolium have dwindled in the wet winters. So the ironweeds are gently but surely demanding my attention and leading the way for how we are going to need to adapt as gardeners.
After seven years in the garden, I will be parting ways with my Vernonia crinita, which at nearly three metres tall is simply too lofty for our windy conditions. This third climactic element is something that puts demand upon the taller perennials that grow heartily in our deep, nutritious soil and on me, as I am trying to limit staking.
In the sand garden, where I have a strict rule of no watering and am experimenting with plants for a drier growing season and a wetter winter, I have been very pleased with the stature of the willow-leaved Vernonia lettermannii. In the wild this fine-leaved species grows on sand bars and along stream edges where water levels fluctuate. Here it has grown so well that I am already beginning to think I should halve the number of plants. When I was visiting Piet Oudolf last week in his garden in Hummelo, he showed me a cross between V. arkansana and V. lettermannii called ‘Summer’s Surrender’, that has finer, more willowy foliage and a demure stature of 60cm or so. It is not yet available in the UK, but being shorter rather than chest height, as my straight Vernonia lettermanni are proving to be, it is a plant I will be looking out for.
When ‘Mammuth’ begins to go over, V. lettermannii will take over the baton and is set to come into its own in October. So far it has proven to be content on our breezy hillside and to provide the sand garden with pristine summer structure and the promise of this late and welcome show of flower. One that provides good late forage for bees, butterflies and other pollinators should we have an Indian summer and, on our return in a fortnight, a welcome home to let us know we have not missed everything.
Words: Dan Pearson | Photographs: Huw Morgan
Published 28 September 2024
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