Diary December 2006 - Shrubs in the Border

I’ve always liked the idea of having a variety of plant material in a Perennial Border. Perennials, as has been mentioned before, have an average bloom time of 2-3 weeks. Then they remain green or turn yellow or fade away completely. Adding deciduous shrubs is a great way to extend the colour season, add variety to the border and fill up space in a hurry! Shrubs are also helpful in blocking out unpleasant views (or unpleasant neighbours!) as well as adding many different types of foliage, lovely fragrance and sometimes even colourful berries. Think of them as the middle layer in the garden bed that helps to blend the trees, flowers and lawn.
What’s the best way to use shrubs in a design? Try a classic trio such as a triangle, a round ball and a square box with horizontal accents. An example of this could be a triangular Japanese yew with a rounded boxwood in front and the airy horizontally-tiered branches of a Doublefile Viburnum behind. Maybe your border needs a focal point. Some shrubs, such as Japanese Maple or Corkscrew Hazel serve this function beautifully.

If shrubs are not used as a single focal point, I advise planting in odd numbers: 3 or 5 or 7, etc. A mass planting of something like ‘Annabelle’ hydrangea creates a dramatic effect with great clusters of white flowers all in a group. I also highly recommend that you research shrub shapes and especially their mature sizes! If you are not careful, a tiny 1’ by 1’ shrub in a little pot will grow into a 15’ high monster in no time! I think one of the most common errors for beginner gardeners is that they forget plants GROW!
Colour is another reason to use shrubs in the border. Imagine the deep purple foliage of a smokebush Cotinus coggygria ‘Purpureus’ underplanted with lime-leafed perennials such as Tradescantia ‘Sweet Kate’, a variety of lime hosta, and Lysimachia aurea as a ground cover. Mix in black tulips such as ‘Queen of the Night’ or ‘Black Parrot’ and perhaps some bright yellow daffodils. Wow! What a stunning combination!!
I love my 2 lilac bushes at the side of the house. In the 20 years we’ve been here they’ve grown to 12 feet high! In late May they are full of deep mauve clusters of fabulously fragrant flowers. They make a terrific combination underplanted with white candytuft, black ‘Queen of the Night’ and pink-striped ‘Estella Rijnveld’ tulips.

Here are some more great combinations:
Japanese Kerrybush Kerria Japonica, with a blue-mist shrub Caryopteris x clandonensis, dwarf barberries and Russian sage Perovskia atriplicifolia;
Oak-leaf hydrangea plus ornamental grasses and snakeroot Cimicifuga racemosa;

Pieris japonica and Mountain Laurel Kalmia latifolia;
Rosa glauca, Cimicifuga ramose ‘Atropurpurea’ and Artemesia ‘Powis Castle’
Dwarf Korean Lilac, Lady’s Mantle Alchemilla mollis and Veronica.

Gertrude Jekyll, the great perennial border designer of the late 19th and early 20th centuries, used deciduous and evergreen shrubs in her masterful gardens in England. Learn form the experts – try using more than flowers in your perennial bed!