It wasn't long before we thought that a specialism might be good for the plant business - a hook to hang it on. We looked at erysimums simply because we had two cultivars in the garden which we liked very much and which seemed to thrive in our dry, sandy soil. These were the small, double-flowered cultivars ‘Harpur Crewe' and ‘Bloody Warrior' - both sensational plants.
Before starting to put together a National Plant Collection, it is a good idea, of course, to check that there isn't already one covering what you want to collect. I consulted the National Plant Collections directory and was reassured that, no, there wasn't already an erysimum Collection. Just to make sure, I also consulted the list of ‘Missing Collections'. But, to my dismay, erysimum was not there either! What did this mean? Was there a Collection ‘pending'? But when I contacted NCCPG Head Office, all became clear - no, there was not a collection being developed already, the genus had just been completely overlooked!
We have built the erysimum collection up to it's current eighty taxa in under four years. And whilst I would not ignore more traditional methods, I would strongly recommend the internet as the main way of collecting. Many smaller, specialist nurseries who did not have an online presence a few years ago now do. And I have found that many nurseries who usually do not do mail order will make an exception for National Plant Collections. And, of course, the internet gives you easy access to nurseries and seed merchants all over the world. I have obtained several cultivars from europe and species seeds from North America. The various plant databases now online are invaluable in sorting out taxonomic issues. And, of course, if you have your own collection website, people come to you (“I've got this erysimum. Here's a photo. What is it and would you like me to send you a plant?)!
The main challenge with the erysimum collection is simply to keep it going - as one supportive nursery owner put it “Great, I was wondering when someone would be brave enough to have a go at erysimums”. The main challenge lies in the short life-span of erysimums - two to four years for many species and cultivars. Given that three specimens of each taxon are required for a National Plant Collection, this means losing and renewing about a third of the collection each year - around eighty plants! Luckily, most cultivars will propagate fairly easily by cuttings, but there are exceptions. I have had, but now lost E. ‘Devon Sunset' - a beautiful cultivar but, try as I might, I could not get cuttings to root. If you know anyone who has it, please let me know!
The short life-span of erysimums is compounded by the fact that they will die early if not kept in the right conditions. All erysimums need well-drained, neutral to alkaline soil. The upright, sub-shrubby cultivars are very prone to wind-rock, which lets damp and disease get at the neck. These taxa need a sheltered site or some support against the wind. The mat-forming and alpine taxa do not like winter wet and are best covered or grown in pots and brought into an alpine greenhouse (cold, with good airflow).
And then there are pests and diseases to contend with. Luckily, slugs and snails do not seem to like erysimums. But Flea Beetles can make a real mess of the leaves. And the biggest threat is mosaic virus, which could wipe out the whole collection if it got a grip. So far, I have been able to avoid a major infection, by getting rid of any affected plants as soon as the symptoms appear. What would really help to safeguard the genus would be to have a parallel National Collection. Is there anybody out there who would like to take this on?
But do I love erysimums despite these challenges? Of course I do! Every new arrival is a thrill. Every cutting from a rare specimen that I've rooted, nurtured, potted-on and then sold to a good home is a source of satisfaction. When my alpine species grown from seed collected 12,000 feet up in the Rocky Mountains flower, do I show them proudly to all visitors? You bet! And when I discover an unknown erysimum growing on the walls of one of Suffolk's Norman castles, am I excited? Of course - hugely! Even in the long winter evenings, when I am researching the history and parentage of different cultivars for the monograph I hope to write, I have the excitement of unearthing pieces of the erysimum story from books, periodicals and websites. And can I imagine I ever had time to go to work? No!