6 Mar 2015

Physocarpus opulifolius ‘Diablo’

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this is an image that reads dress your garden in a little black and has a physocarpus in flower in the background
this is an image of the black leaves and white flowers
Why not dress your garden with a little black this year? Physocarpus opulifolius 'Diablo' is the perfect choice!
 

All of us ladies have a timeless little black dress in our wardrobe; it's versatile and perfect for so many occasions; there's always a style to flatter no matter what our shape and size.  It's just the same with almost black foliage and flowering plants.  They're useful in the garden; they add a touch of glamour; and there are many to choose from no matter what the size of your garden.

 
The late Christopher Lloyd called it 'sophisticated black'.
 
I like having contrast in the garden and one of the easiest ways to achieve that is by planting dark foliage plants with lighter coloured ones. It's a play of light and shadow and it gives vibrancy to the borders.
 
Less is more when it comes to this foliage colour and a little bit of dark goes a long way in giving some depth to a border ...especially in a modest sized plot like mine.  It contrasts so well with many of the flowers and silver leaved plants while also preventing colour clashes when planted in a mixed border.
 
Just make sure your almost black plants are grown in the sunny parts of the border otherwise you'll be creating a 'black hole' and they'll become completely lost. I don't grow the almost black/dark purple leaf plants near each other but have them growing very sparingly in the front and back garden.

Sophisticated Black Plants

Here's a list of what I've grown over the years in the garden that fits that 'Sophisticated Black' look.

 
  1. Heuchera 'Obsidian'
  2. Tulipa x darwin ‘Queen of the Night'
  3. Ophiopogan planiscapus 'Nigrescens'
  4. Viola tricolor 'Molly Sanderson'
  5. Sedum 'Purple Emperor'
  6. Sambucus nigra  'Black lace'
  7. Physocarpus opulifolius 'Diablo'

this is a collage of garden plants that have near black petals or leaves

If you only have room for one large almost black leaved shrub I'd recommend Physocarpus opulifolius 'Diablo' as it has quite a few seasons of interest and it's easy to grow.

 

Back in 1968 Gunter Kordes and Hans Schadendorf from Kordes Nursery found 12 dark leaved physocarpus plants growing amongst 120,000 dull green Physocarpus opulifolius shrubs in a trial field near Hamburg in Germany.    All dark leaved physocarpus shrubs that are available commercially these days originate from these 12 plants.  The dark leaves are due to the high amount of anthocyanins (red, black, blue pigments) in the plant tissue. David Clarke (former MD of Notcutts and holder of the prestigious RHS Victoria Medal of Honour) brought 3 of those original plants back to the UK to propagate from.


...and so our story begins. You'll find this shrub named as either Physocarpus opulifolius,'Diablo', 'Monlo' or 'Diabolo' though the latter trade mark name is the correct one.  In my case I bought it sold as 'Diablo'. 

How to Grow

  • The dark leaved Physocarpus is a deciduous shrub with arching stems which will reach an ultimate height of around 8-10 feet and spread of around 6 feet. Don't let its size put you off as it responds well to pruning and rejuvenates easily from the base of the shrub.

 

  • It's also a very forgiving plant and if you've discovered that you've planted it in the wrong location it doesn't mind being moved in the winter while it's dormant. Just don't do it when the soil is waterlogged or frozen.

 

  • It has a nice vase like shape which means that it's a good stand alone shrub in the border. The RHS website says that it suckers but so far in all the years its grown in my garden I've never noticed any suckering.

 

  • It also doesn't seem to be prone to attack from pests and diseases.

 

  • I grow it to contrast with my late summer flowering heleniums and yellow bronze fennel flowers. While in early summer it compliments the very dark purple and green foliage from the neighbouring Geranium phaeum 'Sambor' - the Mourning Widow.

 

  • It's not the quickest shrub to leaf out in the spring time and sometimes it's been late May / early June before the leaves have appeared.

Growing in my Garden

this is an image of the leavesnbloom garden in augutst

Hardiness

It's a tough, hardy and resilient plant. It came through both of our harshest cold winters a few years ago unscathed and it's listed as 7 in the new RHS hardiness ratings (hardy to -45 °F USDA Zones 2-7). You can't get hardier than that! Not only can it cope with cold gardens but it can also cope with warm ones too as the common Physocarpus opulifolius is a native plant from the USA.

Pruning

You can prune the shrub after flowering if it gets too big for it's allotted space as it flowers on the previous years growth.  You don't want to prune too late in the season as you'll be cutting off next years flowers.  I've never cut back the height of the shrub and so far I've only pruned one old arching stem back down to the ground to restrict the width.

Interest Throughout The Seasons

this is an image of Physocarpus opulifolius Diabolo white flowers against black leaves.
clusters of creamy white flowers contrasting with the dark foliage

 

this is an image of physocarpus diablo
In full flower in June when the leaves are at their darkest

Flowering

In the late spring it has young greenish bronze leaves that mature to a deep dark purple colour.  Then by the middle of June it produces masses and masses of clusters of creamy white cup shaped flowers.  

 

What a contrast in colour that is!   

Pollinators

I can't say if this cultivar is a great source for pollinators - the bees visit the flowers but I don't think it would be one of the most popular flowers to visit unlike some of the others in the garden.  Many new cultivars are bred more for their ornamental interest rather than their wildlife attraction so I'll have to watch it more closely this coming year. I've read that over in the USA the hummingbirds are attracted to the flowers.

Soil Requirements

The shrub prefers an acid soil or one that's moderately alkaline. It needs a loamy soil that doesn't dry out too quickly in the summer.

 

Make sure you keep an eye on it during it's first summer as it can wilt quite easily.

Ornamental Seed heads

this is an image of physocarpus flowers turning to inflated red seedheads
flowers turning to inflated red seedheads
this is an image of the red clusters of seed heads on a physocarpus
clusters of hexagonal shaped seed head capsules in August
physocarpus seed heads
Seed heads remaining on the shrub in November

Autumn Foliage

For me my favourite time of the year for this shrub is during the autumn. Mine grows in a westerly position which is the perfect location for showing off all it's autumn foliage. When the afternoon autumn sunlight hits the leaves I can see burnished gold and orange leaves from my kitchen window contrasting with it's red puckered seed heads. 

this is an image of physocarpus autumn foliage

If I was viewing the same plant from a different position I wouldn't see those colours above and it would just look like the image below.

this is an image of physocarpus diablo autumn leaves

 this is an image of physocarpus autumn leaves

So if you're going to plant this shrub make sure you place it so that you can easily see the back lit leaves as the plant takes on a whole new dimension especially as the stems move in the breeze on a sunny autumn afternoon.

Ornamental Bark

 

Physocarpus can also give us some winter interest in the garden.  If you want to have it's striated ornamental bark then just leave the stems alone. After a couple of years the older stems will thicken and the bark will start to peel away in layers of different colours.

 

Whether it has 9 layers of coloured bark hasn't been scientifically proved but that's how it received its common name - Ninebark.

 

Having so many good attributes who wouldn't want this shrub in their garden if they had the space?   

 

Every year there seem to be more and more newer physocarpus varieties appearing commercially.   If you need a smaller more compact dark leaved shrub I can also recommend Physocarpus opulifolius 'Lady in Red' though I don't grow this cultivar in the leavesnbloom garden.

this is an image of Physocarpus opulifolius ‘Diabolo’ ninebark winter peeling bark

 

 

Follow Rosie Nixon:

Photography Tutor and Gardener

Rosie is a garden photographer, writer and nature lover. She enjoys soaking up nature and is easily distracted from doing the weeding by anything that flutters, flies, buzzes, creeps or crawls! She enjoys sharing the beauty of creation through her photography. Rosie has been featured on TV on BBC2's The Beechgrove Garden and she uses the outdoors as her natural light studio. Her work can be seen at one of Scotland's only photography galleries - Close Gallery, 4b Howe Street, Edinburgh.

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10 Responses

  1. Mark and Gaz
    |

    That's a beauty Rosie that we're considering adding to our garden! And the dark foliage just adds that extra depth too.

    • Rosie Nixon
      |

      Mark and Gaz when I was writing this I was wondering if you had this growing in your garden! There are quite a few newer varieties now so happy physocarpus shopping 🙂

  2. A Garden of Threads
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    I have that same Physocarpus in my garden as well as the native green leaf one. This one can get powdery mildew on very humid years but other then that it is very tough and grows well in my sandy soil.

  3. Pam's English Garden
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    I love your 'Little Black Dress' analogy, Rosie, and Christopher Lloyd's term. I have the heuchera creating a black hole, but for some reason didn't think of moving it until you mentioned it. I have a proclivity for a nine bark, but Physocarpus takes up quite a bit of room and I'm not sure where I would fit it. As you say, I could keep it pruned, so maybe I'll reconsider. I just love your curved borders! P. x

  5. Carolyn ♥
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    Diablo is one of the favorites in my landscape and the bees here really love their sweet blooms. I have several and when they start to look overgrown I cut them down to the base in early Spring and by Summer they are quite lovely again.