When I was at the park on Friday, I cut a couple of shoots from 2C-003 Camellia japonica ‘Blackburniana’ and a couple from 5C-002 Camellia japonica ‘Adolphe Audusson’, put them in a bag and brought them home. There are two plants in section 2C labelled ‘Blackburniana’ and they are completely different. The other one, 2C-004, has flowers that match the descriptions and pictures I’ve seen of ‘Blackburniana’, 2C-003 does not. Unless it is a name that applies to more than one variety, common enough with Camellias, one or both are incorrectly labelled. It was obvious that 2C-003 was wrong.

Because there are around 900 different Camellia varieties in the park, my first thought is whether it might match something else in the collection and ‘Adolphe Audusson’ seemed a strong contender. The flowers looked similar and the two varieties were flowering at the same time. 2C-003 is in the open, which seemed to explain why it was flowering more freely and perhaps why the foliage was a little yellower, the leaves slightly smaller, a little more curled. It was shooting strongly at the base, vigorous growth with healthy dark green leaves. I took a couple of shoots from there.

‘Adolphe Audusson’ at 5C-002 is growing in shade and was pruned hard a few years ago, almost all its growth is strong, vigorous and dark green. I took a couple of shoots from it. For good measure I took a couple more shoots from another ‘Adolphe Audusson’ at 5C-002.

Here they are, all in a row.

Are they identical? Of course not. Even two shoots from the same plant won’t ever be identical. But hold two shoots side by side, turn them in the light, is the glossiness the same, on upper and lower surfaces? Are the leaves the same shape and size? Are the biggest and smallest leaves similar? Do the leaf edges match, serrations along a similar portion of leaf, of matching size and shape? Are the leaves arranged on the shoot the same, the angle, spacing, in the same plane? Are the buds at the same stage of development, are similar numbers of buds starting to grow or staying dormant? Do the shapes of the tips and bases of the leaf blade match? Are the leaf blades flat, V shaped, convex; are their tips reflexed?

It’s not a checklist that you need consciously go through, your brain is a difference machine, look carefully and it will pick up differences that would be difficult if not impossible to put into words. It ceases to matter what the length and breadth of the leaves are, what matters is whether they are the same. You don’t need to know the meaning of acuminate, or obtuse, or obovate to see very quickly whether they match.

In this instance I was convinced the two plants were the same variety. ‘Blackburniana’ 2C-003 has been moved in the collection records to join the two ‘Adolphe Audusson’s. It will be relabelled in due course. I have recorded in the records that I have made the change and why.

I was able to make a similar determination in respect of two plants labelled ‘Geisha Girl’ in section 1M. They are a very poor match for the descriptions and pictures I have seen of that variety, not that I’ve seen much. What they are is ‘Lady Vansittart’, which has comparatively distinctive foliage, making it a relatively easy and confident decision. The downside is that the collection now has one less variety, there being no correct ‘Geisha Girl’, and it doesn’t really need six plants of ‘Lady Vansittart’.

With another pairing, 5A-060, labelled Camellia japonica ‘Valtevareda’, compared with 6-019, C. japonica ‘Monsieur Faucillon’, my confidence level dropped a bit. 5A-060 is one of two plants labelled ‘Valtevareda’, the other being 5D-013. They are similar, in flower and leaf, but they are not the same. 5D-060 seemed the more likely to be correct, if either of them were; it came from a source I have more confidence in and it is a very good match for an old plant at NT Lanhydrock. I looked around for something else in the collection that might match 5A-060 and found it in ‘Monsieur Faucillon’. The flowers are similar, but flowers are variable and they are an undistinguished pink formal double that could be a lot of things. The foliage matches closely, very closely, but not quite closely enough to be certain.

What I need is a third diagnostic feature to corroborate the similarity of flower and foliage and what I am hoping will give me that is the new growth. If the two plants come into growth at the same time and the new shoots and leaves look the same, it will give me the confidence to assign 5A-060 to ‘Monsieur Faucillon’ and label it accordingly. If not, 5A-060 will continue to be identified only by a number. Three factor authentication is the standard I aspire to.

As a diagnostic method, it has served me very well, but only because the collection is very large so the odds of there being a match are quite good. If I have high confidence in the accuracy of the plant I am comparing my unknown to, I would say it was the gold standard of diagnostic methods. Sadly, it is rarely possible to be that confident and I have learned not to trust names just because they are in a famous and reputable garden or on sale from a famous and reputable nursery.

Having used it as a method to good effect over several years, I am aware that it doesn’t always deliver the goods. It hasn’t taught me the difference (if there is one) between ‘Jury’s Yellow’ and ‘Brushfield Yellow’ and I’m no further on with ‘Debbie’ and ‘Debbie’s Carnation’. Nor does establishing that two plants are different, despite their labels, tell you what either variety actually is.

There are a great many Camellias, many of them very similar indeed. What I am absolutely certain of is that it is the method I would seek to use if at all possible. I don’t believe that an identification based on descriptions or photographs alone can be anywhere near as reliable except for a few very distinctive varieties. The trouble with distinctive varieties is that they can cease to be distinctive when you learn that there are other varieties “out there” that are all but indistinguishable. ‘Donation’ is a breeze if you’ve never encountered ‘Fiona Colville’. ‘Devonia’ isn’t clear cut at all once you’ve learned of ‘Charlotte de Rothschild’ and ‘Henry Turnbull’ and ‘Besant’s White Czar’ and ‘White Lily’ and ‘Francis Hanger’ and a few more besides.

Perhaps the most important point is that it is imperative to look beyond the flowers. I gave myself a sharp lesson in practising what I preach a couple of weeks ago. For years I have been taking photographs of a plant labelled C. japonica ‘Lady Vansittart Blush’. I have long harboured doubts about whether ‘Lady Vansittart Blush’ was significantly different from ‘Lady Vansittart’, but based on this one specimen. A couple of weeks ago an encounter with a nearby ‘Yours Truly’, another ‘Lady Vansittart’ sport, made me think about its foliage. No close comparison was needed, 1G-062 is not remotely any kin of ‘Lady Vansittart’. The foliage is completely different. Whatever it is, it is nothing that is elsewhere in the collection so I have nothing to compare it with.

It came into the collection from a keen collector who was importing plants from America, back when that was still possible. I went through all the images in the Southern California Camellia Society Nomenclature, noting possibles, then came to C. japonica ‘T. K. Variegated’. It looked like a perfect match. I did a Google search for ‘T. K. Variegated’, came up with very little, but that little didn’t make me think I might be onto the right thing. The online Camellia register added nothing useful. I have failed to contact the collector, who is very elderly. I have failed to get a response from the one nursery in America who come up as a stockist online.

Plant Heritage, who oversee National Collections in the UK, have an online database for collection holders to record their collections. It allows me to add ten photographs for every plant in the collection. I have been trying to work up a formula for a picture set that gets as close to a direct comparison as pictures will allow. Here is the set for 1G-062. Most of the blooms are white with pink stripes, the other variants are usually present but only one or two of each at any one moment. The blooms are about 11cm across. Bear in mind that in a warmer climate the stamens would probably develop properly and there would be no petaloids. Does it ring any bells? Do you have enough information to make a confident identification? Do you know someone who might know who you could send a link to this post to?

The connectivity of the internet and the ability to take and display high quality images for the world to see, could be a game changer for sorting out such conundrums.