Colour: dense vs diffuse

Most plants present their floral colour in a way that is irritatingly, or at least disappointingly, diffuse.  This is never more obvious than when you take a photo of a plant or combination of plants you’re pretty pleased with, only to find that the consequent pic is 98.5% green and only 1.5% flower.

Then very, very occasionally the opposite is true – that the colour is so densely presented that you don’t know how to integrate it in any sensible or even enjoyable way in the garden.

An example par excellence is provided by Ceanothus ‘Blue Pacific’.  Its spring flowering produces a solid block of electric blue.  The colour is unarguably sensational, but the sheet of unvarying, indigestible colour stands out crazily from its surroundings, and makes a nonsense of pretty much anything else flowering in the vicinity. The only way I can think of really validating it in a whole-garden setting is to use it repeatedly, echoing around the garden, so that it’s deafening chromatic scream can come at me equally from several directions.  Annoyingly I don’t have any pics to illustrate this, but you can see the plant in question here.

The kurume azaleas are a bit the same.  The colour is so outrageously solid that they don’t make any sense in the overall picture unless they’re toned down by something growing up and over them, perhaps, or something growing in front of them, like the single white peony at Wisley (image above).  That way the solid colour just becomes a background for something else, rather than the main – blinding – point itself.

I’m having the same problem with the potted petunias I’ve been going on about in the last few posts.  They were getting a bit leggy in early January, so I cut them back to stumps before going camping.  About three weeks later, the consequent regrowth, which is all at a consistent height, has produced such a solid cushion of colour that I’m tempted to move them away from any of the more modest things in their presence, in an act of floral face-saving.

Having played with colour for years, I know that I like it best when it varies in its density, so often try to use solid-colour plants with others nearby that are capable of diffusing the solidity into the surrounding green.

I’ve always had trouble taking pics that illustrate the point perfectly, but this, taken at Toronto Botanic Gardens doesn’t do a bad job.  The exact same colour is presented in solid blocks by the aster, and rather more sparsely by the geranium.  Using them together allows the colour to intensify and recede, or gather and spread in a way that neither of the plants alone could do.

I was really chuffed when, about Christmas time, a stand of Golden Aurelian liliums bloomed really properly in a very new, incomplete part of my garden.  This they did with no supplementary water, and in a fierce, west facing position in a spot that no one in their right mind would normally have put liliums.  But I’d been told they were exceptionally tough, and so they proved to be, producing huge heads of large golden flowers.  The trouble was that they were the only thing really in bloom at the time and looked, to be quite frank, ridiculous.  They needed to be swallowed up on other stuff – stuff that presented similar or complementary colour in a softer way.

I started to think about what I’d plant them with, and haven’t yet found the perfect combo. I wondered about using Ammi majus (Queen Anne’s Lace), which would provide a nice froth of white to complement the solidity of yellow, but young plants established a month or so before the lilium flowered struggled with the dry.  I considered a tallish blue/purple Salvia like Indigo Spires, but soon faced the fact that there’s no way I could get it up to the necessary height by December in my frost-ridden location.  I wonder if Thalictrum flavum ‘Glaucum’, with its strikingly glaucus divided foliage and fuzzy yellow flowers would flower at the same time?

OK, so we’re not talking about blocks of colour here, but all those great blobs of white from the peony in this Tom Stuart Smith garden at Chelsea ’08 wouldn’t integrate nearly so well without the more diffuse fuzz of white provided by astrantia, just left of centre


  1. Michael, what a question to leave unanswered. The liliums seem to me to need the show to themselves. They are spectacular. Your idea of Ammi maus is tantalising but so many of those gorgeous Apiacious things are difficult in the dry. Last year may have succeeded but this year, well I will start weeping.
    I have a suggestion ; very left of centre. Rhodocoma gigantea. It is one of the S. African restios (Beth Chatto may have something to say). It has the most beautiful arching habit, the older stems are whorls of softness like an elegia. New stems have repeating interesting prominent bracts , in fact one of it’s common names is horsetail though i stress to add it is no relation.. This plant has so much movement in contrast to the liliums which can stand like soldiers saluting.What is more the sienna hues of it’s flower complement the ruby backs of the lilies.
    But i better stop before I have a whole border composed.

    1. Thanks for that Cathy,
      If I’d left it answered, you wouldn’t have felt the need to help…
      I kinda like the idea of something straw/rust in colour (which I assume your suggested rarity is). The pic shows the nearby Calamagrostis, and the straw/gold colour combo had a certain appeal if I lined them up with one eye closed, though it’s not quite the floral explosion I was thinking of.
      I don’t know why no one here (including me) grows the Ammi over winter for spring/early summer flowering. It grows much taller that way, and it would have been OK with the dry, given that it would have been well established by the time the rain stopped.
      Where would I get this..what did you call it?..Rhodocoma?

  2. Lyle at Roramia stocks Rhodocoma. Why is it that these S.African restio’s, of which there are so many, have names that do not stick. I have to look it up in Rick Darke’s book every time.
    I did think of Ampelodesmos mauritianicus , you may remember it at the gate of Wychwood in Tassie but rather thought the straw coloured flowers might be too similar in hue to the liliums. All that proves pointedly is that it is a matter of personal choice

  3. On a much humbler note- I have these liliums planted in front of dark leaved maples and with that dreadful bully bronze fennel around them… Admittedly the fennel is only up to the lilies’ chests when they’re in flower but it’s a nice mix I reckon…

    1. Yeah, I can see that. The foliage of the maples and bronze fennel would link well with that dark stripe on the petals, and the heads of fine yellow flowers on the fennel would be a great diffuser of the blocky lily. Surprised, though, about the height. I would have thought that the fennel would be easily capable of matching the lily for height by Christmas

    2. This is Tassie fennel,Michael, a little more relaxed and slower to get going than its mainland brothers perhaps..tee hee

    3. Sounds like you might need to get hold of some tassie liliums then, so as to align flowering times…

  4. Another post that has me thinking and looking at my plantings with new eyes. I know you’re right about the Ceanothus, but I love it anyway – that sheet of intense colour after a frosty winter is exciting. One of mine is just behind and to the side of a very pale pink crab apple, which flowers at the same time and softens it considerably. I was going to suggest bronze fennel to accompany your lilies, but I see Lee has already mentioned it. Here in Bathurst, it would flower at the same time and at about 2 metres tall. I already have the fennel, and now I think I might get the Liliums, so thanks for that idea!

Leave a Comment

More Blog Posts

A week of indulgence and intent

Talk about serious re-calibration. Through a lot of laughter. We’re one week into our first Travelling Masterclass involving the hungriest group of gardeners I’ve ever travelled with, and we’ve ...

The snobbery challenged - again

Who would have thought that Kurume azaleas could look this good? I’d always been of the opinion that Kurume azaleas with their small leaves and dense flowers were only capable of dishing up solid, t ...