I know that I’ve mentioned before that the National Trust at Wimpole Estate looks after a National Collection of Juglans. One of the reasons that Plant Heritage encourages the creation of national collections is to future-proof the incredible stock of cultivated plants that exists in the UK. So collection holders undertake to conserve, grow, propagate, document their charges. It is a labour of obsession and love.
Juglans mandschurica ssp. sieboldiana is stunningly ornamental tree
I would be interested to know how often other collections get called upon to provide material for propagation, but I know that it is fairly rare request for the walnut trees at Wimpole. However, a few weeks back we were hosts to some visitors who wished to take cuttings of some of the Juglans regia cultivars for grafting and I have to say that it was a great feeling to have the trees serve this purpose.
In fact our visitors, John Bilton and Nick Dunn, are on a tree hunt following a call from the Royal Horticultural Society for information on heritage walnut varieties in southern England. They hope to be able to track down and reproduce varieties trialled in collaboration with the East Malling Research Station between 1929 and 1935. John Bilton explains what they have previously been up to in this Veteran Tree Association newsletter (from page 6).
Back at Wimpole, armed with pruning tools and collection bags, we worked our way around the Pleasure Grounds visiting a list of ~ 10 specimens of interest.
Nick Dunn taking cuttings from J. regia ‘Pedro’
Documenting and bagging cuttings
Good scion material (hopefully)
Taking material from J. regia ‘Tremlett’s Giant’
After a busy morning, Nick and John had collected a decent amount of material from each target tree. The plan is that these scions will be grafted on to prepared Juglans nigra stock. Apparently the chance of a successful graft is higher with this combination. The grafting process will use the hot-pipe technique, which again increases graft success rate.
Hot callus grafting system at Frank Matthews Nurseries (Courtesy Nick Dunn)
Bench graft hot-pipe set up with Aesculus scions (with kind permission Nick Dunn)
Hopefully, the end results will be healthy clean grafts, like this example below.
Bench graft Walnut (Courtesy Nick Dunn)
We should know more later in the year …
Frogend dweller's Blog 
What an interesting glimpse into the inspiring but more serious side of holding a national collection, Nick Dunn’s images provide a nice storyline as to what happened next. Just think, one day those grafts will become majestic trees …..
It was kind of Nick to provide the nursery technical pictures and I hope to see photos of our little babies in a few months too. All v. exciting!
Thank you for introducing this side of NT and Wimpole Estate to us. We have visited Wimpole Estate on several occasions, now I’m looking forward to our next walk on the estate. 🙂
Most of the year they now run daily guided tree walks around the Pleasure Grounds, which you might look out for if you are interested.
I so appreciate the passionate folks who look out for our natural heritage!
Definitely, it was great to be able to tag along and pick their brains! John is really the driving force behind the project and knows so much of the history behind the different varieties selected. It was certainly a privilege to be able to watch Nick chose and collect cuttings. You couldn’t tell which trees he had visited afterwards.
Sounds like a Master. Good mentor to follow around. 🙂
That’s very exciting! Eager to hear how it works out.
It will be a pleasure to keep up with the project!
I use to work in a garden which had a beautiful large black walnut.
Mature specimens are often complete ecosystems on their own and they look glorious in their autumn colours.
Interesting reading and how exciting to be a part of this! It’s always wonderful to see preservation of a country’s national heritage at work.
I had a lovely morning talking to them and watching them work. I certainly felt enthused to try grafting again.
Fascinating to see behind the scenes.
Yes … and now I’d like to go visiting the nursery where they carry out the grafting!