Azaleas and Rhododendrons

Duff and Donna Evers garden in Halifax, N.S

A few years back I came across a very well-dressed couple who were maneuvering a large cart filled to capacity with rhododendrons toward a nursery cash register. 

No doubt they had selected the rhododendrons because their clusters of trumpet-shaped flowers were spectacular, but I had to wonder if they had any idea what they were in for. 

Growing rhododendrons in Southern Ontario is not impossible, but with our hot, dry summers and harsh winters, it is a challenge that is not for the faint of heart. More importantly the soil here is not likely to be the rich, sandy loam rhododendrons and azaleas prefer. Noticeably absent from the couple's cart was anything to amend their soil.

As I watched them take their place in the cash register line up, I couldn't help but adopt the pessimistic view that the future prospects for those mauve rhododendrons was pretty bleak.

Duff and Donna Evers garden in Halifax, N.S

I can speak personally to growing rhododendrons without much of a clue. 

Years ago I bought a rather fine looking specimen myself. I made a half-hearted attempt to amend my soil, stood back and hoped it would just do its own thing.

But the rhododendron sulked and dropped its leaves when the summer got dry. Two years later it was so spindly and pathetic I banished it to the back of the yard. There it mocked me by flowering the following spring.

I was beginning to feel hopeful that my rhododendron might actually begin to prosper when the big tree damaged in the ice storm had to be cut down. Hubby was the cleaning up afterward when he came to me with a rather trampled looking shrub in his hand.

"Was this important?" he asked. 

He was holding what was left of my poor little rhodie!  

(Read an article: Ten Ways to Kill a Rhododendron by Marjorie Hancock here.)

The Dalhousie University Agricultural Campus in Truro, N.S.

Those of you who have been following this blog for awhile will know that last summer I visited Nova Scotia. On the east and west coasts of Canada, rhododendrons and azaleas flourish. There is plenty of rain and the soil is the rich, acidic soil that they require to grow well.

Rhododendrons can be grown elsewhere. We just have to work a bit harder to give them what they want.

Site Requirements:

Notes on the Atlantic Rhododendron & Horticultural Society suggest that site selection is a key consideration. If the planting area you are considering is wet at any time during the year, it is not a good option. Like so many plants, rhododendron's hate wet feet. 

How do you test a site's drainage? 

The Society recommends digging a hole and filling it with water. If the water does not drain quickly, select an alternate location.

The Society also warns against planting rhododendrons near foundation walls on the south and west sides of buildings, as they can become hot spots that rhododendrons do not tolerate well. A roof overhang is also an issue, as they can keep vital moisture from getting to you rhododendron.

One final important consideration- choose a site protected from the wind. Get more tips on siting your plants here.

Duff and Donna Evers garden in Halifax, N.S

Light Requirements:

What do you think: sun or shade for rhododendrons? 

Most people think shade, but in reality experienced gardeners like my friend Donna Evers advise differently:

"Despite what the books say about growing rhododendrons in shade, we have found that in our garden they do better with sun. They are more compact and have a better bud set."

A general rule of thumb with regards to light requirements is based on leaf size. The larger the leaf, the less sun is required. Small leafed varieties require more sun. Generally speaking most rhododendrons need at least half a day of sun.

The Dalhousie University Agricultural Campus in Truro, N.S.

Soil Requirements:

Rhododendrons and azaleas like well-drained, acidic sandy loam ( pH: 4.8-6.0) with lots of organic matter.

Donna, whose garden you see in many of these pictures, passed on this excellent advice about soil conditions that she got from the late Captain Dick Steele, a well respected Nova Scotian rhododendron breeder:

"At first we didn't feed our plants, but then I asked Captain Dick Steele about fertilizing them and he replied, "You feed your kids, don't you?" On his advice we started broadcasting scant handfuls of an all purpose fertilizer (10, 10, 10) over all the gardens. What an improvement it made! We also apply a layer of shredded oak leaves every year. This has improved the soil immensely. Good soil is where it all starts."

Read more about soil requirements here. Read up on feeding hungry rhododendrons here.

Duff and Donna Evers garden in Halifax, N.S

Duff and Donna Evers garden in Halifax, N.S

Planting:

Start by purchasing healthy plants. In colder areas of North America, rhododendrons are best planted in early spring. The American Rhododendron Society recommends planting in fall for hot areas of the country.  

Rhododendrons and azaleas are easily damaged or killed when they are planted too deeply. The top of the root ball should be level with the surface of the ground and planting hole should be larger than the root ball. If your soil is not the light, sandy, acid soil that rhododendrons and azaleas prefer, it is critical to amend the soil with organic matter. 

Find more tips on planting here.

Duff and Donna Evers garden in Halifax, N.S

Duff and Donna Evers garden in Halifax, N.S

Duff and Donna Evers garden in Halifax, N.S.

Maintenance

Rhododendrons and azaleas don't need a lot of care once they are properly established. Mulch your plants with pine needles, oak leaves or wood chips to guard against temperature extremes. Mulching also helps to conserve water. 

One great idea is to cut up your tree after Christmas and place the boughs at the base of your rhododendrons. This little bit of added protection will help prevent them from drying out in winter.

Finally, it is best to remove spent flowers as it prevents seed formation and encourages new growth.

Duff and Donna Evers garden in Halifax, N.S

Pruning and moving Rhododendrons:

I asked Donna for a few notes on pruning and potentially moving rhododendrons. I had to laugh at the humour in her reply:

"We haven't done much pruning except to tidy them up by removing dead branches...We do have to do a little editing this coming spring. Things have gotten a little crowded over the past twenty years. Rhodies have a large, but shallow root mass and are relatively easy to move. The size of the rhododendron and the age of the gardener are the determining factors. Our solution is to give the biggest ones to our kids:-)"

Find additional tips on transplanting rhodies and azaleas here.

The Dalhousie University Agricultural Campus in Truro, N.S.

Duff and Donna Evers garden in Halifax, N.S

This is Rhododendron 'Teddy bear' in Donna's garden. The brown indumentum on the underside of the leaves has a soft, furry texture. Donna tells me that, "Gardeners grow it more for the leaf than the bloom." 

Duff and Donna Evers garden in Halifax, N.S

Duff and Donna Evers garden in Halifax, N.S

Insect and Disease Control

It is a best to seek local advice for the control of insects and disease as problems can vary according to region. Nymphs on the undersides of leaves may cause yellow spotting. Root weevils and stem borer are other widespread pests.

Find ways to address insect and disease problems here.

The Dalhousie University Agricultural Campus in Truro, N.S.

So why would someone like me want to try again to grow rhododendrons or azaleas? My pictures answer the question for me. 

They're gorgeous! 

We gardeners learn by trial and error. If you don't succeed the first time, you can always try, try again.