Tuesday, 27 June 2017

Honesty about Honesty

Mainly about variegated honesty
Why is a biennial called Lunaria annua? Don’t ask me.

White variegated honesty
Biennials are plants which after germination build up their strength in their first year and flower, set seed and die in the second. I am not sure whether the biennial called honesty has read the text book.

Happy accident
My own experience is mainly with variegated honesty. My first love was the mauve flowered type although I think I now prefer the white flowered kind. Much to my surprise you can grow them together without much cross-pollination.

At my first Bolton Percy Open Day thirty five years ago huge drifts were a minor sensation in the cemetery garden. They have remained there by self seeding ever since - although unfortunately not in the same glory. An early memory is scattering seed over a thin layer of ivy. Such is honesty’s strong constitution they grew through it and towered above. I was lucky it was in a wet season.

I potted up spare self sown seedlings
On that first open day my potted honesty seedlings walked from the plant stall. I feel a little guilty now - would they ever have set very much seed? Or even any?

Raising honesty from seed
I will start with the easy bit and follow the text book. Collect the ripe seed in late Summer or Autumn and store in a cool dry place in a paper packet. Sown the next June.It will behave as a it is supposed to do and act as a true biennial. It will make a sturdy plant and by Autumn will have squirrelled away ample resources in a thick tuber-like root. Stimulated by the Winter cold it will bourgeon into strong spring growth and magnificent flower.

If they germinate in Winter they come up variegated.
If they germinate after April they are green

Where it gets complicated is with the variegated kind. More than other types they seem to be opportunistic germinators and self seeded they pop up all over the place in warm spells right through late Autumn and Winter They make a nice display of none flowering variegated seedlings and young plants. The question I currently struggle with is, as I write this piece in February, is to when or if these Winter seedlings will soon develop any flowers. By the time this is posted I intend to know more and if you read to the end whether they set a few seeds and died or went on to make a strong plant for next year  - as biennials are supposed to do! Don’t ask why I cannot properly answer this question having grown them for forty years!

More about the variegated honesty

As the seed head develops the leaves get even whiter - before the leaves eventually die!

I used to sell or give away variegated honesty seed on my first Open days. Sometimes people complained that they germinated as green plants. This is what we want them to do! If sown when the soil is warm this is how they grow. 
Honesty variegation is stimulated by cold. The ideal is that strong green plants from their first year’s growth get their cold in the Winter and accelerate into Spring flower when all the new flower spikes will have magnificent white variegated foliage. I do not know the botanical explanation of this type of cold-stimulated variegation. There are many different causes  of variegation and this one gets short shrift in botany textbooks.

This lavatera is another biennial that exhibits the same phenomenon. In its first year from seed this shrubby plant is dark green
The problem that arises with Winter germinated variegated honesty seed is that all new foliage is from the very beginning intensely variegated and consequently photosynthetically inefficient. Worse although variegation is stimulated by cold, the cold is usually insufficient for these  young plants to flower?

Botanical Note
All  honesty has a juvenile phase when it is incapable of flowering for its first few weeks after germination. Subsequent to this it is still incapable of flowering unless subjected to cold. Botanists call this phenomenon vernalisation - literally preparing for Spring. For honesty this cold period might need to be as long as a total of ten weeks accumulated  when temperatures fall below 5 degrees centigrade. Don’t take this too precisely - no doubt the time varies with plant variety and  cold intensity. As I write this I still don’t know if any of my Winter germinated seed will have enough time to get sufficient cold to flower and - if it does not, does it have the constitution to go on to next year?

Its all clear to me now


The variegated seedlings already illustrated started to grow green leaves and make strong plants
Not very pretty as garden plants
I am now writing in June and the discipline of writing a post has made me closely observe the progress of my Winter germinated seed.
Last year's plant and new self sown seedlings from seed dropped in the previous year
It's always a bit of a nuisance when seedlings come up in the wrong place and some were weeded away. The remaining variegated seedlings made a very pretty carpet under and alongside last years strong plants that were flowering superbly with bold variegated foliage. By May the flowering plants were starting to look untidy and some were tidied away.Others were left to make their beautiful seed heads.
The variegated seedlings were very pretty for quite a long time.They did not flower and as temperatures rose gradually started to make new healthy completely green leaves. They have made strong plants and will make a magnificent display next Spring.

Nobbled by caterpillars elsewhere in the garden this honesty in Summer looks pretty scruffy

A wonderful gardening resource
When researching this post I stumbled on Paghat the Ratgirl’s wonderful gardening website. I have in the past found it to be a very original source of reliable information by someone who has actually grown the relevant plant - unlike most reference garden websites where writers have just trawled the literature and recycle old and often wrong information.
It’s not one of her best efforts on variegated honesty and she concludes that it is not worth growing! Paghat is the only writer I found on variegated honesty who actually mentioned its green growing phase in Summer
I just love her weird website and feel inspired to soon write a post about it! It does not seem to continue beyond 2007 but contains 1600 insightful articles - and that’s just the gardening!

Other kinds of honesty

A friend gave me plants of a bronze foliage variety said to have been introduced by Rosemary Verey
I potted it up to obtain seed
Seed is well on the way
This variegated one reverted!
This perennial strain of honesty grows on the village plot
The seed came from Bolton Percy cemetery
This variegated honesty has set seed in Bolton Percy cemetery

I love my variegated honesty
...but it is perhaps best in the wild garden
...and it looks good on the plot
Hot of the press
My friend Peter Williams finds a place for honesty in his wood




My own previous effort on biennials
As a former lecturer I once felt I had mission to write ‘educational’ posts that go beyond the tat on the television. Roger, dream on  - who wants to read  - or more significantly search for - a piece that combines carrots, honesty and parsley. Perhaps someone might boost my figures that I constantly fret about by hitting this link?


4 comments:

  1. Interesting, I think it is better to sow seed as soon as it is collected as nature intended. Isn't most variegation caused by a problem that the plant has, a deficiency of some sort. Maybe a cold actually destroys something within the plant that makes it create green leaves Maybe it slows down the production of chlorophyll. Guessing here but no doubt you know the answer already.

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    Replies
    1. I do know a little about several causes of variegation but have never read about this particular form that comes and goes depending on temperature.
      I have just googled 'cause of variegation in honesty' The top hit was a very interesting article by Alys Fowler in the Guardian. The third top hit was a typically practical article by Ken Thompson in the Telegraph which explains very clearly many cause of variegation.
      The fourth top was a pretty useless piece - this post!

      My best guess is that honesty variegation is caused by a virus. There are many known examples. Viruses are known to be temperature sensitive e.g. when we catch a fever as a natural control in animals.

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  2. I have grown the white flowered variegated honesty for many years, I cannot say I have noticed the green phase in the leaves, they always look to have some white markings there. This may just be my poor powers of observation. All forms of honesty are welcome in my garden, the ordinary and Rosemary Verey, which usually sells well on open days.

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    Replies
    1. Glad you know the variety Rosemary Verey. I was given it under that name but could not find much confirmation about it on the net

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