Rhododendrons and Azaleas - Tips to have them flourish in your garden

3 min read

Rhododendrons along a white picket fence

While we have some GREAT public gardens in Ontario, including the Toronto Botanical Gardens and the Royal Botanical Garden in Burlington, to name just two spectacular gardens, one trip that needs to be on all our bucket lists is a trip to Butchart Gardens in Victoria, BC, on a day when the Rhododendrons are in bloom!

First – it is an amazing display as many of their Rhododendrons are very mature and very large by our "we have real winter here in Ontario" standards.  Second – it will inspire you to grow both Rhododendrons and Azaleas in your garden here in Ontario! It is impossible to walk through their display in full bloom and not want to run immediately home and plant Rhododendrons.  Ok – maybe after high tea at the Empress, as you are in Victoria after all – but you catch the drift.

To be honest – you need to be inspired as both Rhododendrons and Azaleas are a bit tricky to grow anywhere where we have real winter. Rhododendrons and Azaleas both need winter protection in Ontario gardens as they are evergreen and hold their leaves all winter. Their leaves are a bit delicate and subject to burn in winter plus they set their flower buds in the fall, so we have to keep those buds alive. If that is not enough Rhododendrons and Azaleas also have some picky nutrition and watering needs.  Not impossible – but just a little different than the rest of the garden. 

But trust us – go to Butchart Gardens in spring – and you will want to give Rhododendrons and Azaleas a try!

Rhododendrons are heavy-flowering evergreen plants that enjoy a sheltered and shaded location. Azaleas are also heavy-flowering plants and enjoy a sunny or semi-shaded location.

 

Where to grow
Rhododendrons should be planted where some sun is available to encourage bud formation and compact growth. Shelter rhododendrons from strong winds that dry out the foliage, and provide shade during the hottest part of the day. Rhododendrons must also be protected from the winter sun. In the fall, build a tent of burlap around your rhododendrons and fill the tent with leaves or straw. The leaf or straw mulch can also serve to shelter rodents from winter's frigid temperatures so mouse bait should be placed around the Rhododendrons to protect your plants from the animal's tiny teeth!

Azaleas should be planted in a sunny location but not in a location that is too dry because, like rhododendrons, they enjoy lots of moisture.

 

How to plant
Remove Azaleas and Rhododendrons from the plastic pot before planting. Acidic soil is required for Rhododendrons and  Azaleas. At least half of the planting mix should consist of peat moss to help provide the acid condition. Dig a large hole and fill it with half topsoil and half peat moss. Water your plants well after planting and mulch with bark chips.

 

Moisture
Rhododendrons and Azaleas do not like to dry out, therefore, your soil must be consistently moist but never soggy.

 

Fertilizing
Rhododendrons and Azaleas benefit from an application of acid fertilizers in the spring such as Rhododendron, Azalea, and Camillia Food 4-12-8. Do not overfeed and do not fertilize after June 30.

Do not use aluminum sulfate to acidify the soil. Ordinary sulfur or ammonium sulfate is appropriate. A small amount of sulfur should be added to the soil each year to keep the soil acidic.

 

Pruning
Pruning is seldom required for your Azaleas and Rhododendrons. To increase bloom, you should deadhead the plants and pinch the tips of the new growth in June.

Companion plants that like the same conditions: heaths and heather, mountain laurel, leucothoe, bog rosemary, pieris, bearberry and blueberries.

Deadhead rhododendrons by breaking off spent flowers. Be careful of buds underneath the flower. To increase blooming in rhododendrons pinch tips of new growth in the spring.

 

A few links to three amazing gardens for your gardening inspiration

http://www.butchartgardens.com

http://www.rbg.ca

http://torontobotanicalgarden.ca