Saturday, 24 August 2013

A Trip to Ness - Birch, Sorbus and Much, Much More!!

Earlier this week I made a trip to the north west, to Ness Botanic Gardens in Cheshire, holders of a Plant Heritage National Collection of Sorbus, a significant collection of birches (Betula), along with numerous other plants of botanical and horticultural significance.

A view across the rock garden at Ness
My particular area of focus on this visit was the aforementioned collections of Betula and Sorbus, and I had arranged to spend the duration of my visit in the company of Dr Hugh McAllister, who co-wrote the recently published Betula monograph (as mentioned previously), along with the Sorbus (rowans) monograph,published in 2005. The gardens botanist, Tim Baxter co-hosted my visit which happily coincided with that of Paul Bartlett, manager of Stone Lane Gardens, which I visited back in May. We had the further pleasure of being joined by the much travelled and esteemed plantsman Chris Sanders. All set for some serious plant study

Among those looked at early on were specimens of B. megrelica and B.medwediewii, two similar shrubby species from Georgia. The former is restricted to Mt. Migaria with little is known of it and Paul was particularly keen to study the Ness specimens in comparison with B. medwediewii, as those growing with him at Stone Lane Gardens are very similar, though growing side by side here the differences in leaf size, shape and texture along with shoot colour were quite apparent. Having studied B. medwedewii in the wild recently (his report is available here!), Paul is keen to return to Georgia shortly in search of B. megrelica.

Hugh and Tim discussing B. megrelica and B. medwediewii...

Paul collects foliage samples for comaprison with the plants at Stone Lane Gardens

Continuing through the garden we observed a fantastic specimen of Populus glauca. One of the large leaved or necklace poplars (section Leucoides), we admired both its foliage and form - a fantastic tree, growing very well!

Populus glauca at Ness. It's glaucous foliage is apparent, even in this photo! 

We then came across another birch I had observed (and been given a specimen of for Westonbirt!) at Stone Lane, B. ashburneri, though this was a larger example than any I had seen there. Not far from this was a seedling grown on from this species, which although of possible hybrid origin (with the closely related B. utilis) is regardless a fantastic tree with great horticultural potential.

A plant grown from a seedling of B. ashburneri, showing good promise

After a brief pit-stop, we began to focus slightly more on some of the pinnate leaved Sorbus, as well as numerous other woody subjects en route. Many of the Sorbus held fruit at various stages of ripening, with some looking simply stunning!

Fruit and foliage of Sorbus aff. vilmorinii

Sorbus sp. KR6918

The distinctive foliage of Sorbus helenae. There was barely any fruit left on this specimen,
with the birds particularly fond of it! 

Eventually moving out of the more formal areas of the garden into meadow, we studied further birch and Sorbus species, observing a particularly fine young specimen of S. aff. wilsoniana that Chris is particularly fond of. With it's glossy foliage and fruit held in large clusters, it really is a great tree with true horticultural value!

The fine young specimen of Sorbus aff. wilsoniana with fruits yet to mature

This part of the garden (down towards the Dee estuary) formed much of the area used by Hugh for the research for the Betula monograph and it is an immensely valuable site to study the different provenances of Betula species. It was great to see far more variation within different species than you often come across in cultivation, as well as being highly educational!

Bordering the site the diversity continued and whilst to the uninformed the boundary may appear to be comprised of more common species of birch and alder (Alnus), it is packed with rarities and recently introduced material! A truly fantastic resource!

No ordinary hedgeline!! 

Moving back towards the more formal areas of the gardens we passed by some old nursery beds, again replete with an array of arboricultural goodness! Passing along the top one of the beds, my eye was caught by a specimen of the Acacia relative Albizia julibrissin, which was an unexpected treat! Having seen this most recently at Cambridge University Botanic Gardens last month, my only experiences of seeing it had been in areas in the eastern United States, where it enjoys the hot summers (and a little too much in some areas further south, where it has become invasive). Neighbouring this tree was what appeared to be a specimen of Eucommia ulmoides. Not entirely sure at a distance of 30 or so feet, myself and Tim ventured through a near impenetrable body of bramble to seek confirmation. On reaching the tree and tearing the leaf in half for evidence of latex (a tell-tale i.d feature of the species), I was delighted to find that it was indeed EucommiaFantastic! Brushing past (or more accurately avoiding being torn by) an Aralia elata on the way out we made our way to a bench where Chris had taken a seat. Informing him that it was indeed E. ulmoides, as he had suggested, he remarked that we could have saved ourselves ten minutes there, but hey, you gotta do what you gotta do!!

Tim amid the trampled undergrowth, in front of the Aralia, Eucommia, Albizia et al

We then worked our way back up towards the nursery, where Chris gratefully received a fine selection of plants to take away with him. All in all, a fantastic day amongst the trees!

Aside from studying the plants growing in the collection, I had brought with me from Westonbirt a number of specimens (both birch and Sorbus!) for identification/verification and Hugh, Tim and I spent a few hours around a table in the library at Ness on Wednesday morning observing the finer characteristics of these, making more than a few re-identifications of specimens along the way! The pinnate-leaved Sorbus can be a particularly confusing group and like many collections Westonbirt has (or had!) it's fair share mis-identified plants, owing to a combination of factors, including having specimens of unknown and hybrid origin as well as cases of perpetuation of names mis-used in the trade, to add to the confusion!

Having dealt with the Sorbus specimens,
Hugh studies one of the trickier birch, as Tim refers to the book

Among the specimens for identification were those that had only been identified to genus level and among these there certainly some of particular interest. Along with wild sourced S. pseudovilmorinii were three that proved to be S. munda. Hugh informed me that this has been collected only once, and though we have no accession details of these particular plants, we now know we hold some of the original material! Such occurrences highlight the value of the verification work we are undertaking and helps increase the value of the collection whilst informing us as to our future management plans.(More on our Sorbus later!).

So having had a fantastic time out in the gardens (I have given only a mere snippet here!) and studying leaf and fruit samples, I now have myself quite some work to do in amending and updating the all-important database here at Westonbirt. And oh yes, keep a look out for a few label changes!!