Sunday 2 June 2013

Dicentra cucullaria, Dutchman’s breeches

How to grow Dicentra cucullaria

You have to be quick to enjoy this woodland fringe N.E. American native. Barely two months after its emergence in March it is gone. But what a two months. From the emergence of its delicate filigree foliage it rapidly produces exquisite white flowers. Reminiscent of dutch baggy pantaloons it produces short columns of elegant white flowers. If you are feeling a little whimsical, you might imagine them to be inverted trousers hanging out on a line. Too quickly the plants die down.
Delicate filigree foliage emerges in early March

Dicentra cucullaria tubers revealed when I have scraped away alpine mulch in June. Best to plant the complete tuber rather than divide into scales

This rare dicentra dies down to charming tiny pink clustered tubers, which if left in the ground return in abundance each year. Peter planted some in his woodland garden and forgot they were there. When he later disturbed the soil he inadvertently broke up the tubers and propagated them around. Next year he had a wonderful display! Note this would not happen to the digger or regular soil stirrer who would kill them! 

In the wild they grow in a leaf-mould rich soil in light shade. This woodland fringe plant also grows in the cracks of bare rocks. They seem to enjoy my own gravel mulched areas. Many of mine receive full sun for much of the day. If you think this sounds all too perfect you are right!  Slugs and snails love them and this year some of my precious pink Dicentra cucullaria ‘Pittsburg’ were grazed to the ground by mice! 

eaten by a mouse

As holder of the National Dicentra Collection I need to keep my stock secure and I grow many of my plants in pots. This small delicate plant lends itself to this technique and although my pots of cucullaria are normally outside all year round, I sometimes bring a few inside as they burst into flower to make a March/April greenhouse display. Groups of pots can also be plunged in large tubs for outdoor display. I remember many years ago a magnificent display of my cucullaria at Harrogate Spring Flower Show. Plunged in a large salt and algae encrusted clay pot it was the highlight of the Plant Heritage stand.

Dicentra cucullaria varieties in the National Collection

I have three distinct varieties…

Dicentra cucullaria common form

Dicentra cucullaria ‘Pittsburg’

Dicentra cucullaria ‘Pink Punk’
Growing in pots.
Thirty years ago I was thrilled when a lady gave me a large pot of strong tubers. I had previously struggled with pathetically weak nursery bought plants. My purchased plants had been propagated by breaking up the tuber cluster to pearl-barley-like scales. What is wrong with this is it that it takes years to build up a strong plant.
I find it quite sad that when I divide pots of valuable vigorous plants ‘in the green’ to sell on my Open Day, if they are not in full flower, nobody buys them at all! It’s a complete waste of time!
Although I use my own sandy-soil compost, for most people, a soil based mix like John Innes 2 is best. To develop new stock I crumble out dormant undivided tubers, usually about June. I plant about ten tubers at about an inch depth in a deep 2 litre pot. The pots are then parked well out of the way at the base of a hedge!. If I remember, I lightly top dress with an NPK general fertilizer in October and again in January.  Apart from keeping them weed free I do nothing else. 

Delicate foliage emerges in March
Rain provides the only watering the pots need until shoots emerge in March. They then rapidly make luxuriant, yet delicate, growth. This strong head of foliage is very susceptible to drying out  when strong late Winter winds blow. By the time of full flowering the plants might need generous watering every day. On the other hand if it is wet and windless, they need no watering at all. That’s gardening for you! I only repot my plants every other year.
Plants in the ground need no watering or fertilizer at all.

Dicentra canadensis,  squirrel corn, a similar tuberous plant.

I grow it in exactly the same way as cucullaria. Sadly it is endangered in the wild.

Dicentra canadensis, squirrel corn

Dicentra canadensis can never be misidentified, the root tubers of squirrel corn look even more like maize seeds than my own sweetcorn!


  1. The white flowers look to me more like stylised flying doves than a Dutchman's breeches. I'm very impressed that you are the holder of the National Collection. Respect!

    1. You are quick off the mark, Mark! I have only just posted. Sorry I am feeling frivolous this morning!
      As to respect, I think it might evaporate if you knew how easy it was get approval 35years ago and if you saw the state of my records and labelling now!

  2. The cucullaria are beautiful plants. I love the tinge of colour by the trousers waistband!

  3. They're actually quite pretty. Interesting shape on them though, like at any time they are going to take flight.
    Cher Sunray Gardens

  4. Roger, your post could not have come at such a perfect time for me. I was going to scour the internet tonight. I've been growing D. cucullaria Pink Punk for the first this spring. Dormant plants were bought from my local nursery (reputable). Despite putting on plenty of leaf they failed to flower. They have now died back and still haven't found a home in the garden for them yet.
    My question is - Is it ok to plant them out now or should I wait until next spring? I should add they are still in the 9cm pots I bought them in. Thanks in advance.

    Your plants are lovely one and all. Holding the national collection must be some commitment and I can appreciate how important it must to to ensure your plants are in tip top health. Sorry to bother you with a question.

    1. Hi Angie,
      I love to have questions. I wish there were more,as long as they are relevant to the post, as is yours.
      You are a year behind me with your ‘Pink Punk’. I received two small tubers 18 months ago as a result of a swop for another dicentra via an e-mail request. Like yours last year it did not flower and mine was quite weak. I labelled it well, a rare thing for me! And then in June parked it under my greenhouse bench (it could of course stayed on the bench or been put outside in its pot as I describe in my post). Under the bench the dormant tubers would be quite dry but essentially would get wet occasionally when water spilled off the bench! Most of my collection outside in pots just gets wet when it rains.
      When my plant emerged in February it was a lovely surprise as I had forgot it was there! An essential detail, my greenhouse is completely unheated.
      I think there might be some merit in repotting your new tubers into a slightly bigger pot now. Either just pot-on the complete pot or if you crumble them apart be sure to reuse all the old compost, otherwise you might miss some small tubers!

      It is probably best not to plant your dicentra outside until after a couple of years you build up your stock. That’s unless you know better and already have other cucullaria thriving outside and you know you have the right conditions. Peter Williams down the road has a natural woodland ‘glade’ rich in natural leafmould where cucullaria grow well, I would risk my own precious stock outside in his ideal conditions.

      If you do decide to plant outside it does not really matter when if you plant the undisturbed pot. Do not attempt to crumble apart the tubers after Autumn, I suspect they start to make new roots well in advance of sprouting.

    2. I have just reread my answer. When I said 'undisturbed pot' I did not mean planting the pot!

    3. Thanks for a very detailed response Roger, your advice is much appreciated. I'll pot them up into a slightly bigger pot until they are a bit more mature. I will probably slip them under a bench too - I do this with a few plants I know are hardy enough but haven't got round to planting out if the ground is frozen or too wet.
      I did cotton on that you did not mean planting the pot - I'm not at much of a novice ;)
      Thanks again for sharing your experience and knowledge.

  5. So interesting you have the national collection of Dicentras, you must have many of them. I did not know the Dicentra cucullaria, very pretty plant, but Dutch baggy pantaloons, hahaha.

    1. Nice to have the dutch connection Janneke.
      Seriously Dicentra cucullaria is called Dutchman's Breeches. Unfortunately too many gardening articles use the name for all dicentras- as they also do with the name 'Bleeding Heart' which is the common name of Dicentra spectabilis!

  6. I have a small patch of the D. cucularia, but for some reason it has gotten smaller.

    1. That's the problem I have found, Jason. If the outdoor conditions are not perfect and akin to those in the wild they deteriorate.

  7. I grow quite a few "woodlanders" but have never considered Dicentra as a possibility but I certainly will now. You live and learn! Most gardens had what I think was probably D.formosa many years ago, but it seemed to be superseded by the more showy D.spectabilis types. Perhaps more interestingly I have also grown, the beautiful D.scandens which did well outside until the calamitous low temperatures of three winters ago. I now believe the climbing Dicentras have been transferred to the genus Dactylicapnos, does that mean they are now excluded from the National Collection?

    1. No, we are are not as sophisticated as that! Dicentra spectabilis is now Lamprocapnos for example but I still have all of them in my collection. I am sure there are possibilities for anyone who wants to have National Collections of these new genera if they can persuade Plant Heritage they have the time and 'know how'. In fact I would be personally delighted if there was a duplicate dicentra I am 71 and as mentioned my labelling is not very good......
      You can quickly raise new plants of Dicentra scandens and D. macrocapnos by getting seed on the net from Chilterns. If you are quick you might just get them flowering this year!

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