Underplanting

“Eh?!  What’s that?” you ask.  Well, underplanting is a really nifty and easy concept in gardening that magnifies the impact of the plants you put in.  We grow plants we are attracted to.  We place them in clever combinations that look good.  We place them in the ground and stand back and look, and think, “what a pretty plant”.

Underplanting makes the plants you love sing.  It adds harmony to the tune; it gives instrumental accompaniment to the beautiful voice.  It transforms your pretty plant into a little bit of art.  When the whole garden is not yet out, it makes a “whole” out of the parts you do have.

Tulips underplanted with Forget-Me-Nots
Photo: Charles Cresson on the American Flower Garden, 1993, Burpee Expert Gardener series

It turns “what a pretty plant” into “what a pretty garden!”

Characteristics of plants that work well for underplanting usually include having a little bit of frothiness or spread.  They cover the base and soil around the plant you pair them with, and add layering and contrasting texture.

Not all of the low-growing plants that work at the front of a flower bed are necessarily great for underplanting.  Spiky things such as Dwarf Irises don’t add enough horizontal coverage for this purpose.  Overly-aggressive or dense things such as Phlox Subulata, Creeping Phlox or Snow-in-Summer may sometimes compete too hard or choke out the plant they were supposed to complement.

Perennials, annuals and even shrubs can be used for underplanting, depending on the size of the plant you wish to underplant and the season in which you need results.

Underplanting is a little different from “edging” or from straightforward “plant pairings” or combinations, and has different objectives.

What can be underplanted?  Plants that look good

The bare base of the rhododendron invites underplanting. Photo from http://www.vdberk.co.uk

underplanted are those whose vertical stems spire out of the earth without anything to beautify the base of their stems.  Tulips and other taller spring bulbs do this, many spiky perennials do it, shrub Dogwoods do it and so do many other deciduous shrubs such as spireas and Weigela.  They need “finishing off” somehow.  An example of a plant that does not need underplanting is a foxglove, whose flowery spike emerges from its own low-lying bed of silvery leaves.

So, if you plan to hit the nurseries this weekend or feel your garden is in need of a hit of something to banish the blahs, have a look at what is blooming and get it a friend.  There are many options, but here are a few suggestions that I like:

Forget-Me-Nots  This classic underplanting with its wispy magical quality creates a starry prettiness in the spring garden, and pairs best with tulips (top photo) but is versatile.  Other plants it looks good with are ferns and Peonies.  In

Forget-Me-Nots brighten bare branches in early Spring

my garden, it independently decided to underplant a grouping of Silverleaf Dogwoods.You can see it just beginning to bloom here, with the dogwood twigs spiking out of it.  Notice how it covers the bare soil, polishing the look of the original shrub planting.  I also love its dainty froth of flowers against the rugged, grey stone.

. . . and here they underplant a small Rhododendron*

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Yank it out after it blooms to control it, or you may end up with it everywhere.

Golden Creeping Jenny   This is a good one to underplant other plants that are relatively short, because it creeps right along the ground.  Qualities that make it a top underplanting are its stunning gold colour and tiny oval leaves, which contrast and set off other plants, as well as its gentle treatment of other plants (in spite of rapid growth) and surprising nearly-evergreen resilience.

I have it lying low under pink Hyacinths which gives an Easter-looking effect, and have started some  beside dwarf Irises to contrast their blue-green spiky leaves.   In planters, it contrasts and brightens spiky grasses, purply Autumn Cabbages and Asters and will trail sweetly over the edge and down the side as it grows.

Some gardeners don’t like poor Jenny, but I do.

Grape Hyacinth   These are another good pairing for other spring bulbs, but won’t amount to much the first couple of years.  They can spread wildly, though, so before you know it, they will form a thick carpet of blue (or purple or white, as you choose) under taller bulbs.

How do these hungry spreaders get along underground with other bulbs, without one starving the other?  The Grape hyacinth’s bulb sits very shallow in the ground, while other, larger bulbs they accompany are planted several inches deeper.  This way there is nutrition and room for everyone.

Pansies   Because they are so tough and resistant to temperatures lapsing back to freezing in early spring, and have those large, flat, upward-tilted little faces, these annuals are great for planting under tulips.  Also, you can

Spring planter with pansies

use them to underplant other plants in spring planters, and I use pansies for this purpose every spring.

Impatiens   Another annual that is a nice underplanting because it spreads nicely and does not compete with others.  Impatiens love shade, so they are a relaxed, pretty complement under and in front of the stems of ferns.  For a peaceful look, choose white.

Euonymous   This is an example of one shrub that can be used to underplant others.  Voted most likely to be seen with Silverleaf Dogwood or Red Twig Dogwood.  For more on this, please have a look at my post, “Lovers in the Garden“.

Euonymous underplanting Dogwood.

In the above photo, these dogwoods have variegated leaves, so I paired them with a euonymous whose leaf is not variegated.  I don’t like to combine more than one variety with a similar pattern of variegation in the same grouping.

Hosta   Hostas make a good underplanting for twiggy shrubs in part to full shade.  Since there are so many colours and leaf shapes to choose from, you can find one to bring out the best in any larger plant that needs a friend in

Photo: http://www.lammscape.com

summer (although don’t bother trying to use them for anything in early spring, since they leaf out too late).  My favourite combination of course, is Hosta Albo-Marginata underplanting Annabelle Hydrangea.

Bergenia Cordifolia    In early spring, this plant sort of underplants itself:  sturdy, bright pink or white spiky flowers arise out of the leathery, broad leaves for a while.  However, its greater value is those leaves, spreading over and covering the earth in shady places with a layer of unique, evergreen texture, grey-tinged in cold weather and bright green later on.  They are the ideal plant to use around Rhododendrons, another stunner we purchase that nonetheless has no good graces of its own at ground level.

Dicentra, Bleeding Heart   Although not low-growing, this is a beautiful thing to plant under larger, woody shrubs.  In particular, I love the stunning effect of pink and white bleeding hearts planted under fully-grown Lilacs with similar bloom time, completely covering their indecorous bases.  This gorgeous photo is from Fine Gardening magazine.

English Ivy   Another plant that flourishes in the shade, it works best with things that it can’t choke out.  The beauty of it, though, is four fold: its very dark green colour, its leathery-texture, its easy-care nature and its proliferation in the shade.  It also covers slopes nicely.  It underplants a garden of  Birch, Dogwood, Peonies (strangely enough) and ferns on the east side of my house.

Cotoneaster  Ever since my visit to U.K. gardens 13 years ago, I have had a soft spot for this English garden staple.  I use low-growing forms of it to combine with shrubs and trees in garden areas devoted to textures and foliage.  It will quickly cover bare earth around the  taller plants, and loves sun and shade.  Its shiny, dark, round green leaves and red fruit in autumn make a stunning contrast with any type of blue evergreen needles.  In summer it diverts us with a flush of white flowers.  Bonus: it is another evergreen.

Cotoneaster underplanting shrubs and trees

I will never forget the many plantings of Cotoneaster with Purple Smoke Bush or Purple Barberry, and Aruncus Dioicus, Goatsbeard, in the British gardens in June.

Do you have a favourite plant that you have used for underplanting?  Please share your suggestions by leaving a reply, below.

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