My 2014 Pacific Rhododendron Adventure

Since late April, I have been visiting Deception Pass State Park at intervals.  On Saturday, I returned to the park once again.  My quest has been the grove of wild Pacific Rhododendrons growing on the lower south flank of Goose Rock.  This never ceases to be an amazing experience for me.  In the deep shade under the canopy, a network of trails leads through this old growth forest.  It's a dark, two-tone world of greens and browns.  Then, suddenly, I am confronted with this:

The incongruity is startling.  Where a bit of dappled sunlight penetrates the trees, the Rhododendrons have found a spot to their liking.  I have wondered why they grow in this location, but not in other similar environments in the park.  The U.S. Forest Service database provides some clues.  First, they grow in association with coniferous trees, pines, firs, cedars and hemlocks.  Soils should be moist, but well drained with a balanced supply of moisture.  Rhododendrons are indicative of low soil nitrogen content, and they have shallow roots.  A mycorrhizal fungus around the roots assists in the uptake of nutrients.  Good soil aeration is important.

Deception Pass State Park lies within the Olympic Rain Shadow.  The annual rainfall is about 20-26 inches/50-66 cm.  The characteristics of this specific site include a south-facing hillside which might capture a bit of extra rainfall from prevailing storms.  The exposure may produce a microclimate that is a little warmer than other sections of the park.  The site is adjacent to Cornet Bay which is surrounded by hills.  The bay could add some extra humidity in the rhododendron grove.  Some of the rhododendrons are growing from the trunks of fallen trees or nurse logs.  The decaying bark is fibrous and holds moisture.  This gives seedlings an extra chance of succeeding.

I have spotted numerous seedlings along the Southeast Summit Trail.  There is more sunlight here and the presence of Madronas is indicative of well-drained soil.  Along the shadier Lower Forest Trail, there are young and mature plants, but no seedlings that I have seen.  Over time, the conditions may have changed here making the germination of seedlings less likely.  Or perhaps I just have not searched well enough.  This trail defines the western edge of the grove.

The Pacific or Coast Rhododendron (R. macrophyllum) is the Washington State Flower.  It ranges west of the Cascades from spots in southern British Columbia to coastal northern California.  The scientific name translates to "rose tree with big leaves."  Some of the leaves in the grove are a foot long.  The flower clusters are called trusses and appear at the ends of the previous year's shoots.  New shoots for next year's bloom sprout from the base of the flower as it goes to seed.  You can determine the approximate age of a rhododendron by counting the joints in the limbs.  Climate conditions during summer and fall when the flower buds are setting can determine the quality of next year's bloom.  For example, severe drought during this period might result in a poor bloom the following year.


In shadier understory locations, the growth habit is tall and rangy.  Some Pacific Rhododendrons can reach 30 feet/9 meters in height.  In sunnier spots, the plants will be more compact.  The shrub is evergreen, usually holding its leaves for two years.  After new leaves appear on this season's shoots, the two-year-old leaves will die and drop off.  You can watch this same process in your garden rhodies.

Pacific Rhododendrons can be grown in gardens where conditions are right.  They are sometimes available in nurseries or local native plant sales.  If your garden includes some large conifers, you may have a good spot for this understory shrub.  If you live where Pacific Madronas are growing nearby, that is another indicator of a good site.  I planted one in my garden, but the poor thing was quickly ravaged by root weevils.  This is a garden pest they may never encounter in the wild.  They apparently lack any resistance to it.  There is evidence of chewing on the leaves in the grove, but nothing like what happened in my garden.  When I try again, I will be prepared for the attack.

Never, never dig up wild Pacific Rhododendrons or support this in any way.  Because digging them up will disrupt the mycorrhizal fungus in the roots, the transplant will undoubtedly fail.  Of course, rhododendrons in state and federal parks are protected.  Look for plants that have been cultivated for gardens from domestic stock.

All of the photos in this post are from last Saturday's visit to the grove.  In a forest setting, these wild plants are every bit as beautiful as their cultivated garden counterparts.  Adding to the experience, I was serenaded by ravens in the canopy on this visit.  Enjoy this gallery of wild Pacific Rhododendron photos.

In the previous post, I mentioned finding this native orchid, Western or Spotted Coralroot (Corallorhiza maculata).   It was growing at the upper end of the Lower Forest Trail.  The photo on the left is the same plant showing the flowers have now completely opened.  View the photo full size to see the little spots.  On the right is a second Coralroot I found growing nearby.  There are many interesting plants besides rhododendrons growing all over Goose Rock.  These were challenging photos of plants growing in deep shade.  In these woods, I have gotten a lot of experience taking photos at ISO 3200.

There are many reasons to visit Deception Pass State Park.  There is something here for just about everyone.  If trail running is not your speed, try exploring the park at a more leisurely pace like me.  You might discover something you have never seen before.  This is my second season visiting the Goose Rock Rhododendrons.  Last year, I barely began to learn my way around the site.  This year, I also found the parasitic little Naked Broomrape and I finally got to photograph Common Camas and Chocolate Lilies.  I had seen Spotted Coralroot in other locations, but not at Deception Pass.  I met some new friends which also made this season extra special.  I am already making plans and looking forward to next year's visits.