Wednesday, February 9, 2011

Beyond Rhodies and Junipers

I swear when we first moved to the Seattle area in 1996 I was convinced that nurseries only sold rhododendrons, azaleas and monster junipers. The typical suburban garden appeared to have little else unless the homeowners were especially adventurous and added a few impatiens for a splash of summer color. Unimaginative didn’t even come close.

If you insist on growing rhododendrons, at least choose pretty ones!
The cinnamon colored indumentum on this R. 'Teddy bear'
 leaf complements the tones of the 'Heuchera Creme brulee'.
My design
Thankfully times, nurseries and attitudes have changed. With the wealth of TV garden shows, gardening publications and the internet showing us other peoples gardens all over the world we are far more energized and inspired to create a real ‘garden’ not just a foundation shrubbery, designed by landscaper 50 years ago as a way to hide the lower part of the house.

However we can still be susceptible to similar pitfalls. Let’s face it when you visit a nursery you are naturally drawn to whatever is at its ‘peak’, whether that means roses in June or Witchhazel in February. So, if we only visit nurseries occasionally and impulse buy our favorites that day we are likely to still have a very seasonal garden.

One key group of plants are the evergreens which provide the 'bones' of the garden; conifers, evergreen trees and shrubs and also evergreen perennials. I shared a few ideas for the best conifers for small gardens previously. In this post I want to focus on broadleaved evergreen shrubs – other than rhododendrons! I am also going to restrict myself to those plants which have proven to be reliably hardy in our recent frigid PNW winters and omit beauties such as hebes, Pittosporum, strawberry tree, 'Little Gem' Magnolia and ‘Spring Bouquet’ viburnum from my list. I know there are plenty of readers fortunate to be able to grow these without any problems but I share the frustration of those who thought they lived in zone 7 and find themselves in zone 6!! It’s just too cruel to tempt you with the ‘maybe’s’.

A dark clematis weaving through
'Sundance' Mexican orange blossom
Sunny areas

Firstly let’s dispel the myth that evergreen plants are boring, offering only dark green leathery leaves with an elliptical or tapered shape. If privet, laurel and boxwood tend to immediately spring to mind think again. Want bright foliage? Try ‘Sundance’ Mexican orange blossom (Choisya ternata). This will sparkle in sun or partial shade although it is best protected from a hot western exposure. Glossy yellow leaves, fragrant flowers in spring and fall (a good friend of mine insists they smell of cat piss – I think he needs to see an ENT specialist…) and a nice compact shape to about 4’ which can easily be trimmed make this a five star broadleaf evergreen. There are plenty of yellow variegated shrubs too, such as wintercreeper 'Emerald and gold' (Euonymus fortunei), variegated silverberry (Elaeagnus pungens 'Maculata'), variegated false holly (Osmanthus heterophyllus 'Goshiki'), variegated boxwood and variegated holly if you  want just a little sparkle rather than the full floodlight effect.


Variegated silverberry
Need an attribute other than color in your sunny border? David’s viburnum (Viburnum davidii) is a handsome mounding shrub with heavily textured leaves and bears clusters of metallic blue berries on red stalks. Darwin’s barberry (Berberis darwinii) may be covered with thorns but the sprays of bright orange flowers add a welcome splash of color against the small dark green leaves and if used as a hedge can be an effective deer deterrent. Parney’s cotoneaster (Cotoneaster lacteus) forms a loose fountain of green foliage, each leaf displaying silver on the underside. Summer flowers and abundant red berries make this a favorite of winter birds.

Perhaps it is fragrance you long for? What about the spring blooming Delavay osmanthus (Osmanthus delavayi), literally covered in fragrant white flowers in May. Just trim after blooming to control the size if desired.

For finer textures look to the soft fern-like foliage of heavenly bamboo (Nandina domestica) in shades of green, chartreuse, red and plum. They form a perfect contrast to the bolder dark green leaves of cotoneaster or viburnum for example.
Heather 'Wickwar flame'
(Calluna vulgaris) in winter color
Heaths and heathers revel in full sun and many sport foliage which change color during the season. ‘Wickwar Flame’ for example is brick red in winter changing to softer green in spring while ‘Spring Torch’ changes from winter purple to green tipped with cream, orange and red in spring. The box honeysuckle (Lonicera nitida) is a great low maintenance evergreen with sprays of small leaves held stiffly from the main trunk. ‘Baggesens Gold’ is  bright green, ‘Lemon Beauty’ has green and chartreuse variegation and 'Red Tips' blushes year round.


The finely textured box
 honeysuckle provides a soft
 backdrop for the hellebores.
My design
Looking more for silvers? Daisy bush (Senecio greyi syn. Brachyglottis greyi) has felted silvery white leaves and clusters of yellow daisy flowers in summer. Personally I don’t care for the flowers and cut them off. This shrub looks great paired with blues or purple.

Shade gardens

Shade gardens can still look interesting even after the hostas and ferns have gone dormant for the winter. For sheer architectural quality you can’t beat the tropical looking Japanese aralia (Fatsia japonica). This thrives in good soil, easily becoming 8’ tall and wide with funky sparkler type flowers in spring. They can also be used as container specimens but withstand winter temperatures more reliably in the ground. Oregon grape (Mahonia species) also offer bold texture with their large holly-like leaves.

Pieris 'Forest Flame' bears its fragrant
 white flowers at the same time as
 the colorful new growth bursts forth
 
For fragrance there are lots of options from andromeda (Pieris cultivars (including several variegated forms)) with their lily of the valley fragrance, winter daphne (Daphne odora ‘Aureomarginata’), sweet box (Sarcoccoca species) and leucothoe which is available in several colorful cultivars including 'Scarletta' and 'Rainbow'. Andromeda also has outstanding color in the new spring growth; typically a bright coral-red which can be emphasized by underplanting with the similarly colored Heuchera 'Peach flambe'

Problems and prevention

During the winter evergreen plants continue to lose water by transpiration, the loss being greatest during periods of strong winds and on bright, sunny days. Desiccation occurs when water is leaving the plant foliage faster than the roots can replenish lost moisture. Root absorption is reduced or prevented when the soil is cold or frozen. The foliage of plants, such as camellia and boxwood, may turn yellow or orange due to mild desiccation or excessive sunlight with more severe injury commonly seen as discolored, burned evergreen leaves. Damage is normally worst on the side of the plant facing the wind or sun or near a reflective surface (white house, concrete paving, snow cover).

 
The bold evergreen leaves of the Japanese
aralia form a striking combination with the
Japanese forest grass.
Photo credit; Alyson Ross-Markley
When planting broadleaf evergreens that are known to be easily injured, such as some cultivars of, azalea, camellia, and daphne, select a location on the north, northeast, or east side of a building or other barrier where they will be protected from prevailing winds and intense winter sun. These exposures will also delay spring growth, thus preventing injury to new growth or flowers from late spring frosts. The worst location would be the south side of the landscape with no shade and exposure to windy conditions. Avoid planting tender plants in low spots that create frost pockets and sites that are likely to experience rapid fluctuations in temperature. A 3-inch layer of mulch will also reduce water loss and help maintain uniform soil moisture and temperatures around roots.

Special precautions can be taken to protect plants during the winter. Anti-desiccant compounds such as Wilt-Pruf are sold in garden centers and online and many gardeners have found them helpful.

Winter is a good time to re-evaluate the garden as it reveals the quantity, quality and variety of evergreen plants which are the main workhorses of good garden design. With so many great plants to choose from, is it time to thin out those giant rhododendrons that haven't bloomed for 20 years anyway?

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