Tuesday 7 July 2015

Confessions of a lapsed dicentra collector

Attempting to leave a record

Thirty years ago I was delighted to be awarded the National dicentra collection but I now wonder if I was handed a poisoned chalice! 
It’s not as if one is given the plants in the collection. You have to find and pay for any plants you acquire. Having the National Collection does gives a little credibility when you ask someone for seeds or a plant. I have been sent  seeds from around the world although anything ‘difficult’ usually fails!
No other ‘volunteer’ has come forward to hold a duplicate collection or hold a particular section. I am starting to worry that when I portal my mortal coil that no one will know what I had got or where to find it…or care.

Some dicentras are not easy to grow. Forms of Dicentra peregrina are for me personally impossible. Even peregrina hybrids with Dicentra eximia and formosa are difficult. I hold out great faith for a new three way hybrid ‘Amore Rose’ which I recommend you seek out. It has a strong constitution, delicate fine foliage and pink/red flowers all summer. 
(Two months after writing these words I am starting to wonder. Now in July it is looking rather tired but then so do normal dicentras. And my peregrina hybrid ‘Burning Hearts’ has died yet again - but the roots did come in shocking condition from my normally favourite bulb supplier!)
 Delicate young leaves and flowers emerge in late March in my unheated greenhouse. I potted up the sturdy plant from Edrom Nurseries on the day of receipt.

It has provided three months of continuous flower, mainly outside. (See my problem with colours!)

I have lost ‘Burning Hearts’ yet again!
I intend to mainly confine my comments today to Dicentra formosa and Dicentra eximia. Naming  of these in the trade is hopelessly confused as I have previously reported. The epithets ‘formosa’ and ‘eximia’  are interchanged with ignorant abandon. It is 95% certain that the form that you personally have in your garden is formosa and you will know from it’s  characteristic long rhizomes and dumpy flowers.

 Look carefully at the flower and then at the flowers of the Dicentra formosa flowers in the rest of this post. They are very different

A seed raised eximia doing very well in a moist shady corner of Cathi’s garden
How can I say that something you might find taking over your garden is difficult to grow?
For a start Dicentra eximia - well for me anyway - has dubious perenniality. It does not live long in my soil and has to be restored from fresh seed which it fortunately sets freely. If your conditions  are really suitable it will self seed itself but if you get a bad germination season you might very well lose it.

Dicentra formosa is generally easy but brings it’s own problems and different cultivars vary in success from season to season and garden to garden. This year for example the very similar ‘Bacchanal’ and ‘Cox Red’ have had real difficulty in making headway in the persistent cold drying winds. I have had to save my rather weak plants by lifting and potting and placing in my  cold greenhouse.
Several years ago I was privileged to meet nurseryman Adrian Bloom. Dicentra ‘Adrian Bloom’ is a very fine red. (I saw it recently on the net as a very fine pink!). We bantered that he could not grow his red namesake but red ‘Bacchanal’ grew for him very well. In my case it was the other way round!
Just like my previous garden ‘Adrian Bloom’ grows much better than ‘Bacchanal’ (not pictured)

Why Dicentra formosa is difficult to collect and maintain

1 Some varieties - but not all - seed themselves freely and germinate in abundance in February and March. Seedlings are not true to type and are usually inferior and left to themselves will take over. Embarrassing to me when a red one comes up pink! Vigorous wonderful reliable glaucous-blue foliaged Dicentra formosa oregana ‘Pearl Drops’ does not do this but many others do. In fact some varieties self seed so freely that I regard them as a seed-strain.
A former student recently sent me this nice picture of Dicentra ‘Pearl Drops’

Seed strains differ in detail but broadly conform to some general characteristics - unless they have cross pollinated with others. I do not now recognise my original ‘Bountiful’ and the original plant is long since dead! Never-the-less the self seeded off-spring in a fairly isolated part of the garden in respect of pollination conform to a similar pattern. At one time  I would buy garden centre plants to check on my naming. Last week I walked past an alleged and un-flowering Bountiful on a garden centre display stand and was not even tempted. It was bound to be wrong!

The pictures below are all self sown plants from ‘Bountiful’ - but who is to say that my original plant was itself not a nurseryman’s seedling too?

This Dicentra 'Bountiful' is starting to set seed
I have another self seeding formosa that I call ‘The Parcevall Strain’. The parent plant had been donated to me thirty years ago by colleague Ernie Oddy who used to do volunteer consultancy and work at Parcevall Hall.

The pictures below are of the Parcevall strain

2 Many varieties are not genetically stable. Although I am intensely interested in matters genetic I really don’t understand this. It might be an unstable gene for colour that mutates easily. In gardener’s terms this is called ‘sporting’. 
‘Aurora’ is a relatively new variety that might be described as ‘tinged white’. I now have two variants that are very nice pinks.

More pink than white in this sported ‘Aurora’
Many years ago I selected for myself a very nice strong free standing pink seedling which I privately refer to as ‘Roger’s Pink’. I now have four vegetative variants. One of them has delicate fine foliage. 

3 As mentioned you cannot be sure of the correct identification of cultivars that you buy. Nurseryman sometimes inadvertently sell similar seed sown plants. ‘Stuart Boothman’ is a wonderful pink variety with very delicate foliage. I have bought it several times and they all look different. It is alleged that clonal material from the original Stuart Boothman plant was retrieved from his housekeeper’s garden. A lady from Scotland sent me a very fine delicate leaved dicentra and I think it is the same one.
 My plant from Scotland (not this one) grew well to make a huge clump and then suddenly died. I do have some plants in convalescence!

A difficulty with Dicentra ‘Stuart Boothman’ is that it’s delicate fine foliage only occurs in slightly starved plants. In the early days we took the students to visit Oxford Botanic Garden. Mr. Cleverclogs pointed to the label and declared to our guide that it was wrong. To my shame the label was right - the plant had received very generous nutrition. You might remember from the post listed below that Oxford’s record with dicentra naming is not very good!

4 Some Dicentra formosa are genetically stable and although they do not cause confusion seeding themselves around they do have variable colours within the same clump. Nancy Boydell’s dicentra, ‘Furses Form’ and ‘Spring Morning’  all three illustrate this phenomenon.

The above two pictures were taken side by side within the same uniform clump and in the same light. Nancy Boydell, an early hero in the history of Harlow Car garden, gave me this unnamed plant

 This stable yet varied cultivar will be completely swamped by Lobelia tupa in July. It has continued to thrive for many years

5 Variable colour is always a problem. It can vary with season, level of shade, soil type and temperature. This Spring has been rather cool and my colours have happily been ‘true’ ones which have lasted very well. In a  previous post I have published a picture of Dicentra ‘Roger’s Pink’. It is a genuine picture but bares little resemblance to the colour I recognise.

6 Many nurseryman are rather cavalier about naming. Especially imported ones sold at garden centres. I recently read in a trade magazine that named varieties of Dicentra formosa could be grown from seed!
A nurseryman offered Dicentra eximia alba ‘Snowdrift’. I was sure that it would be formosa rather than eximia and of course it was. As I do not have genuine ‘Snowdrift’ I contacted the nurseryman to enquire about it’s provenance. He quickly backed off and admitted it was from seed!
A real difficulty here is whether ‘Snowdrift’ ever truly existed or was it just a nurseryman's fancy?

Restoring my collection
In my confession I have admitted that my plants are all over the place and only I know what they are - on a good day! Some I know because of the whereabouts of the plants with which they intermingle! I am afraid permanent labels are something foreign to me.
 I am starting to rationalise my collection. I have discovered after all this time that I can propagate by division small pieces when they are flowering in May. (I normally propagate from Dicentra formosa rhizomes just before or immediately after their shoots emerge). This is very useful to know because I can rescue small plants when I have a clear identification of them. Even better if some of my plants have sported or self sown a rather nice seedling I can furcul them out and pot them up. I tease out such young plants and immediately pot them and place in my greenhouse away from the vagaries of the weather, especially the wind.
Now in July I have been very pleased to find that that plants propagated in this way have done rather well. (Well not Cox Red, it survives on a thread).
Now I must work out where I am going to plant them!

I am reviving a dark form of ‘Stuart Boothman’

I propagated my new plant of  ‘Dark Stuart Boothman' from here!
I always recognise this dicentra because of its coexistence with my phlox! It was given to me by Mrs Davies holder of the National Allium collection. She called it “my dicentra” and I have retained her name

This chlorotic form of Dicentra formosa circulates in the trade in various guises with ‘gold’ in the name

I believe Dicentra ‘Pearl Drops’ and ‘Langtrees’ to be identical and probably ‘Silver Beads' too. All are the subspecies Dicentra formosa oregana
This photograph of D ‘Silver Beads’ growing at Kew  seems a little dwarfer and pinker but the quality of culture suggests that the plant’s procurement might be similarly flawed
Dicentra ‘Luxuriant’ is probably the most common formosa you will find in the catalogue. When I buy a plant to check my stock not only is it usually different, it normally dies. I will blog one day about nurserymen growing soft plants in poly-tunnels and despair of garden centre watering! If I do get it to grow I find it disappointing. This is the best I can do but have no confidence it is the right one
Links to all my dicentra articles
I intend to publish more dicentra information in future. Eventually I will  bring it together in a special blog section. In the meantime you can find my dicentra posts in the links below. They are also in my theme column but unfortunately the older posts do not seem to display.
My first dicentra post includes a discussion of the misidentification of eximia

The story of Dicentra 'Snowflakes' and more about Dicentra formosa alba
The climbing yellow dicentras
A famous botanic garden gets its dicentra labeling wrong (end of corydalis post)


  1. I'd be worried to death if I had a national collection. Then again I don;t know which plant I would choose. I never realised that there were so many different dicentra, I love the foliage

  2. Thanks for this great post, and I had a look at your other previous posts too, I didn’t know you had the national collection! Do you sell plants too? I would be interested to add to my collection when I get my shade garden more sorted.
    I have had ‘Bacchanal’ for about 7 years and in February I split it in 3 – the main plant is doing fine, but the other two are still struggling a bit to recover, possibly because they all are in pots. I bought ‘Aurora’ from a nursery 3 years ago, got it in the late autumn in a 2 litre pot without leaves, planted it the day it arrived – and never saw it again. Would love to try again, but after reading your post that it can appear pink rather than white, maybe not – the whole point was to have a white one. ‘Amore Rose’ looks lovely, would love to have it! I am collecting a wish-list for my shade garden and the colours will be white and all shades of pink. I have quite a lot of plants already from my previous garden but have room for more.

  3. Thanks for your appreciative comment HELENE. As you know I am following the development of your new garden!
    Afraid I don't sell plants but if you go to RHS Plant Finder you will find sources of white ones even if the nurseries call it D. eximia!
    I recommend the bog standard Dicentra formosa alba and D. spectabilis alba as good white ones. 'Pearl Drops has the best constitution of the formosa varieties but as you see from the pictures it is rather an off white! If you have trouble sourcing plants contact me privately on my google address.

    My friend Rowena from Preston often queries me about white plants for her white border. Three excellent whites I have recently brought to her attention are Zantedeschia (Excellent for wet Preston!)
    Dictamnus alba and the white form of Ipheon. My Schizophragma petiolaris has really strong white flowers which I am looking at now out of the window!

    1. Thanks for your suggestions Roger, I took with me my D. spectabilis alba (no, I haven’t started using its new name yet….) so it will go in my shade garden, and I have a magnificent Zantedeschia, growing in a container, it gets a couple of litres of water EVERY day, and seems to love it. I have wondered how I could plant it on the margins of my new shade garden as it is already too big for the large container it is growing in – a sunken old bathtub has crossed my mind but I can’t face all that digging! I also have a collection of tricyrtis along with a lot of other shade plants from my old garden – but I lack some good flowering plants.

      The shade garden has complete shade and very light dappled sunlight only part of the day. Not sure if Dictamnus alba will take that, it says full sun or part shade. Also looking for evergreen plants that can take full shade – with flowers in white, cream and pink shades. I am trying to re-create what I had in my old garden with a succession of flowers all year round and as many evergreen plants as possible in every bed so no bed is completely empty in the winter. I am getting some divisions of Saxifraga stolonifera in the post tomorrow, hopefully they will be happy in my shady bed :-)

    2. Perhaps your Zantedeschia would thrive in the ground if you watered it as often as you do now. Perhaps it could be in a slight depression.The downside of being in the ground is that hungry tree roots would want to share the water.
      I have a fine specimen in a fairly dry part of my garden but it gets watered every time I water my tubs - and there are no near trees!
      My dictamnus is in half shade but heavy shade would not be suitable
      Wondered about suggesting Geranium macrorrhizum alba

    3. Thanks for suggesting Geranium macrorrhizum alba, it’s a good plant for the area around the stems of the ceanothus’ where it will probably always be rather dry – next to the fence and in deep shade. I will put it on my list!

  4. Fascinating stuff as always Roger, I can't remember if I read in your earlier posts why you chose Dicentra as a subject but I would still be interested to know. Unfortunately I have to go with the "grumpy old man thing" the way that plants are grown today is purely to appeal to the ignorant buyers in the local garden centers, not only that the efforts of the RHS to introduce some kind of hardiness scale seem to have gone by the board, not that it was going to be much use anyway.
    I do despair of how keen novices are to be educated when the whole industry seems to be intent on burying itself in an ever deepening hole.

    1. I chose dicentra because I liked Dicentra spectabilis and I thought that as there were not so many dicentras it would be suitable for a small garden. I once told somebody that I had no special knowledge of the genus and he answered that I soon would!
      I agree with you about limited opportunities in horticultural education -both for professionals and amateurs.
      I would be unable to properly advise a young person on how to make a career in horticulture now


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