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Rhododendron and
Azalea News

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Spring 2010  Vol. 13  No. 1
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Gardens

Planning your garden

Don Hyatt, Mason-Dixon Chapter, knows all the ins-and-outs of creating and designing beautiful gardens.  He outlined some of his thoughts in the chapter's newsletter.  It's planning time with spring bursting out all over...and listen to some of his guidelines.

For a rhododendron and azalea garden, plan the empty space first.  With annuals or low-growing perennials, one's consideration is with the flower bed...but when plants grow tall...such as rhododendrons...it is much better to plan the open area because tall plants will make walls in your garden.

open spaces enhance a garden...

The open spaces will become "garden rooms".  Consider traffic flow from one room to another...either by wide connections or with winding paths.  Once you have defined the open areas, you are free to plant everything else...as flower beds!  Consider how to treat the various spaces defined in the landscape.  Should there be "open spaces" to enhance vistas, "corridors" for transitions between area, "closed spaces" for privacy, or "extensions" of the home interior?  Consider movement between areas and access routes.

design for easy maintenance...

Design for easy care, avoiding plans that require heavy maintenance or constant pruning.  Wide paths are better than narrow walks...since the latter often become tunnels over time.  If the soil is poorly drained or plants won't grow easily, choose an alternative...such as mulched areas or slate.

Consider costs, too!

apply principles of art to landscape design...

There are basic principles in designing. They are:

  • Form and Mass. The mature landscape should be in scale with its surroundings.  Plants give the garden form, so mass plantings will be more effective than mixed groupings as gardens age.  A planting of 5 to 10 azaleas of the same variety will look much better than a mixed planting as the garden matures since the plants will have grown together to look like one large specimen plant.
  • Line. Graceful and irregular curves are more interesting than straight line and sharp angles.
  • Color and Harmony.  Choose colors and varying leave textures that go well together.  Color schemes should be harmonious and compliment each other and any existing architecture.
  • Emphasis and Contrast. Place light colors again dark ones for emphasis.  Include plenty of white and neutral colors to blend or provide transitions.  For gardens with brilliant shrubs like azaleas and rhododendrons, it is wise to allow for at least 50% of the plants to be white or other soft tones to allow the eye to have a visual retreat from the more intense colors.  In addition to white, pale pinks and yellows...such as those in some of the Knap Hill azaleas like 'Marina' are good blending colors.  Personally, I like to use soft blue as can be seen in the native wildflower, Phlox divaricata.
  • Balance and Repetition. Informal, asymmetrical balance is preferred to symmetry since formal designs with shrubs become a liability over time.  A large planting on one side of the yard can be balanced with a small but similar grouping on the other.  Repeat colors and forms.
  • Unity. Everything should go together. The garden should enhance the home architecture and the community. Simplicity is desirous...but often difficult to achieve for a plant collector.

selecting the right rhododendron and azalea varieties...

 
  • Choose varieties that will grow in scale appropriate for the landscape needs.  Some azaleas and rhododendrons can be used as ground covers while others will be trees.  Use dwarf varieties in the foreground or constrained places.  Use large growers in the background or for screens.
  • Some varieties are not adapted to each climate, especially rhododendrons developed in cool moist climates that object to hot humid summers.  Varieties developed in the Eastern U.S. are often safer choices for the Mason-Dixon area.  Most evergreen azaleas grow well for us.
  • Consider time of bloom.  Some varieties flower very early and may need frost protection while others bloom late and might require more shade to extend bloom time.
  • Change the color scheme by selecting plants that bloom at different seasons.
  • Use many companion plants.

 


Wild rhododendrons of Mount Elphinstone

Anyone who has taken a Spring trip through Manning Park has probably noticed the beautiful pink-flowering shrubs lining Highway 1 (in Canada).  These magnificent plants are the Pacific or Western Rhododendron, R. macrophyllum.  Members of this species are also found in the wild near Nanaimo and Shawnigan Lake on Vancouver Island.  However, on the Sunshine Coast's Mount Elphinstone, are found the most northerly stand of macrophyllums in the Pacific Northwest

a little history...

The Pacific Rhododendron was named macrophyllum (large leafed) because at the time of its discovery, there were no known rhododendrons with bigger leaves.  Although several Himalayan rhododendron are now known to exceed macrophyllum in leaf size, the Pacific Rhododendron at least has the distinction of being the tallest of B.C.'s native rhododendrons.  It has large, jade-green leaves and twenty or more flowers are in each dome-shaped truss.  These blooms can vary in color on different specimens, from various shades of pink to white.  The species range extends from Southern B.C. to Northern California and from sea level to 2000 metres.  Macrophyllums are common in Washington and Oregon...but are rare in British Columbia.

Dr. Ben Hall, a geneticist, adds to information...

 

I first learned about R. macrophyllum growing wild on the Sunshine Coast from reading an article by Dr. Ben Hall, a geneticist, in the Winter 2006 issue of the Journal American Rhododron Society.  He described a visit to Mount Elphinstone four years ago by Sunshine cost environmentalists and members of the Vancouver Rhododendron Society who collected flower and leaf bud tissues for him.

Dr. Hall used these samples in DNA studies which proved that Mount Elphinstone's R. macrophyllum population is a distinct genetic variation of the species.  Along with small populations in Washington State, these rare rhododendrons, referred to as the Clade 1 type, prefer to live hear salt water.

In June 2006, at the peak of the bloom period, I as able to find a guide to take me to the Mount Elphinstone rhododendron grove.  We drove for several kilometers along rugged logging roads and finally reached a clear-cut area containing a tiny island of forest about 300 meters wide and twice as long.

an outdoor cathedral...

  As we walked from the harsh sunlight into the forest area, I felt as I had entered an outdoor cathedral.  Under my feet was a thick carpet of yellow moss.  Above my head, shafts of sunlight broke through the second growth Douglas Fir canopy.

Then, all of a sudden, the rhododendrons appeared in front of me.  They were gigantic...some over four meters tall!  Many had side branches that extended an equal distance outwards.  There seemed to be about a dozen individual specimens...although it was hard to tell...because many had layered new plants from low-growing branches.

All of the rhododendrons appeared to be in good health and sported vigorous new growth.  Their leaves were glossy green...with little inset damage...and no indication of fungal disease.  Flowering was profuse, with huge light pink blooms appearing on every plant.  Best of all...I found some ten-centimeter tall seedlings growing out of two well-rotted logs that were near the edge of the grove.

After the visit, I contacted Brian Smart, planning forester for the District of Sechelt's Community Forest.  He told me that he had visited the Mount Elphinstone rhododendrons and assured me that, the Community Forest Advisory Committee (CFAC) is excited to have these rare and beautiful rhododendrons within the Community Forest Tenure area.  "We are looking forward to working with the rhododendron societies to develop a proper protection and management strategy.  We are also interested in the idea of assisting with propagating these rhododendrons within the Community Forest area."

In October 2006, Dean Goard, past-president of the Victoria Rhododendron Society, joined me at the Elphinstone grove to collect seed pods and cuttings.  Since then, he has been able to root some of these cuttings, and pot up over 100 plants grown from seeds.  They should be ready for transplanting in the fall of 2008.  Some will be available for garden testing on the Sunshine Coast and on Vancouver Island.  Others will be offered to local foresters to be planted in a remote...but already-protected forest area on the Sunshine Coast...hopefully, to form a satellite macrophyllum population.

The wild rhododendrons of Mt. Elphinstone are a local treasure.  We can be proud of the steps that are being taken by Coast residents and the CFAC to protect this very rare native plant.

 -- Ron Knight

 

 
Word power...with Bruce Palmer of the Eureka Chapter  

The word is "allelopathy"...a dollar-a-pound not related to rhododendrons directly...but it is pertinent in case you are thinking about planting a rhodie under an Eucalyptus tree soon. Allelopathy stems from the Greek allele for another or one another and pathos for causing harm. Roughly translated it might be read as poisoning your relatives.

In genetics an allele is one of a pair of genes controlling a characteristic, flower shape, for example. Quite a few plants...especially trees, secrete harmful chemicals that ward off pests or reduce competition in the area immediately surrounding themselves. That is called "allelpathy".

In the case of Eucalyptus, the leaves and seed pods contain resins that, when dropped to the ground, inhibit the growth of new plants, including other Eucalyptus. That's why we don't see other plants growing successfully under Eucalyptus trees.

There are lots of other examples of the process. It comes about because plants don't have kidneys or livers to get rid of toxic by-products from metabolism. Among trees it is common for them to store toxins in the dead inner cells in their trunks, the dead outer cells of the bark, or in the leaves or seed pods. When the leaves, outer bark or seed pods are dropped, the poisons go with them. Often these metabolic by-products are not toxic to us but are very aromatic. Thus, we have bay leaves, cinnamon bark, and cloves. If the by-products are stored in the inner cells in the trunk they don't poison the tree...but may yield great smells as with the camphor wood or fantastic colors beloved by woodworks from trees...such as mahogany.

So, don't plant your rhodie under that Eucalyptus...but the next time you cook or admire a piece of furniture...be grateful...that trees don't have kidneys.

   
A gem to remember...  

There is material enough in a single flower
for the ornament of a score of cathedrals

   
Editor's note  

Yes, dear friends, there is so much to share about real gardens, tours of gardens, and how to plan and prepare for your personal garden. This past year has had its limitations. Now, I look forward to sharing with you...and you...and you...around the world!


American Rhododendron Society
Executive Director: P.O. Box 525,  Niagara Falls, NY 14304
Ph: 416-424-1942   Fax: 905-262-1999   E-Mail: lauragrant@arsoffice.org
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