Mt Edgcumbe has two plants of Camellia sasanqua ‘Setsugekka’ and one of ‘Kenkyo’, or does it?

In section 3C are two plants which are labelled C. sasanqua ‘Setsugekka’. According to the collection records both came from Stonehurst Nursery and were planted in 2003. In early March 2018 a large tree fell on top of one of them, reducing it in size by around 75%. I tidied it up and it has made an impressive recovery, with strong new upright growth of 6-8 feet in the four seasons since. Last year it produced the first flowers since the mishap and it is flowering again this year.

Prior to 2018 I never had cause to consider whether the two plants were identical. They flowered at the same time and looked very similar, they’d come from the same source, they had the same label; I took them to be the same. Looking back at old pictures they look the same.

However, to look at them now it is hard to believe they are the same variety. The plant that was trashed by the falling tree is growing very strongly and has healthy lustrous dark green foliage. The other plant looks to be in poor condition. It is making very little new growth and its foliage is comparatively yellowish and spotted. Like many seriously stressed plants it is flowering as if this might be the last year it gets a chance to but the flowers are a little smaller than they should be.

Camellia sasanqua ‘Kenkyô’ is at the other end of the collection, in section 1G. It has a label on it saying Camellia hiemalis ‘Chansonette’. ‘Chansonette’ is described in the Register as having formal double flowers in strong brilliant pink so the name is clearly wrong. The records show that it came from Coghurst Nursery in 2002 and a few years back I checked their website to see whether they were listing anything that looked like it. Back then ‘Kenkyô’ was in their catalogue. ‘Setsugekka’ seemed like a contender too, based on pictures and descriptions but similar though they are, it isn’t the same as the two plants in section 3C. Eventually I found a plant labelled ‘Kenkyô’ at Trewithen Garden and was able to compare it closely, reaching the conclusion that they were the same.

It has been suggested to me that the two plants of ‘Setsugekka’ might in fact be ‘Kenkyô’, meaning that the 1G plant might in turn be ‘Setsugekka’. It doesn’t help the cause that the blooms on both varieties are somewhat variable, especially on the one I’ve been taking to be ‘Kenkyô’, so a single picture of a bloom in a book could probably match either plant and photos of foliage, which might help corroborate a tentative identification, are seldom provided.

I have been looking for characteristics on the two varieties that might support the floral evidence and the first problem is that the two plants of ‘Setsugekka’ are so different. It seems to me that I must first find characteristics that are common to both plants in spite of their differences and to then compare those characteristics with ‘Kenkyô’.

I reckon the leaves of ‘Kenkyô’ are larger and don’t taper to the apex as quickly. The widest point of the ‘Setsugekka’ leaves is often nearer the base than the apex while in ‘Kenkyô’ it rarely is and may be nearer the apex. The extreme margins (0.5-1mm) of most of the leaves of ‘Setsugekka’ are turned down slightly whereas the leaves of ‘Kenkyo’ are usually flat to the edge. Some of the leaves of ‘Setsugekka’ have bases which are rounded, as in the third leaf above, while ‘Kenkyô’ bases usually have a narrower angle.

On another occasion I took pictures of the flower buds of ‘Kenkyô’, thinking they looked like they might be distinctive. I didn’t at the time follow up with pictures of the buds of ‘Setsugekka’ so that’s one for next time I’m up the park.

The two bushes of ‘Setsugekka’ are upright, ‘Kenkyô’ is wide spreading, and ‘Setsugekka’ was into flower a week or two earlier than ‘Kenkyô’. I’m not sure I’d trust either characteristic to be the killer blow.

I’m trying to think as if I was keying out the two varieties using a botanical key. Single to semi-double flowers, opening flat, of a certain size, autumn flowering, just the occasional touch of pink. That gets you down to maybe three to five varieties, but homing in on just one takes a few more details. A person very familiar with all the contenders would perhaps recognize which was which at a glance, without necessarily being conscious of exactly why they knew. That’s not me. I want someone to say that you can always recognize ‘Kenkyô’, or ‘Setsugekka’ or whatever by some specific, unique character or combination of characters. Here are some more pictures.

‘Kenkyô’ 1G-014

‘Setsugekka’ 3C-027

Are they ‘Kenkyô’ and ‘Setsugekka’? Do I have them the right way round. And, crucially, how do you know?