dwarf rhododendrons

By Ron Knight

The gardens of most city dwellers would be classified as small ones.   In that kind of space, annuals and small perennials look right at home.  However, trees and tall-growing shrubs can present problems if the homeowner hasn’t planned the garden with the mature size of those plants in mind.

Everyone has seen examples of homeowners (and landscape professionals) who have planted a new perennial garden, filling all of the available space with cute little trees and shrubs.  For the first couple of years the garden looks great, but after that, the plants begin to grow into each other and their beautiful individual shapes are lost.

Enthusiastic new rhododendron collectors often make the same mistake in their quest to display as many as possible of the plants they have heard rhododendron experts say are “the really good ones”: R. augustinii, R. macabeanum, Lem’s Cameo, the Loderis, Sir Charles Lemon, etc.  They purchase dozens of young plants in one and two gallon containers, placing them a metre or so apart throughout the beds and borders of their small garden.  Inevitably over time, the collection becomes little more than a sea of green for 11 months of the year.

As an alternative, rhododendron lovers with small garden spaces might consider using mostly dwarf and semi-dwarf specimens.  As a rough guideline, these are the plants that Harold Greer describes as reaching 3 feet or less in 10 years (Greer’s Guidebook to Available Rhododendrons, Offshoot Publications, Eugene, Oregon, 1996).  Of course, all rhododendrons keep growing after a decade but dwarfs do so at a very slow rate. 

Most dwarf rhododendrons are evergreen. They have showy flowers in a wide range of colours, plus dense foliage that is attractive all year long.  Varieties are available that will provide garden colour from February through July.  Dwarfs look fabulous in containers, require minimal care, and are susceptible to few pests.  Most are very tolerant of wind and sun.

In fact, dwarf rhododendrons should be planted where they will receive maximum sunshine.  Many will become leggy and less attractive when planted in the shade.  Dwarfs need to be located as far away from aggressive tree roots as possible.  They coexist well with mosses but are happy not to associate with most ground covers.  Instead, they like a covering of mulch over their roots, but not grass clippings, peat, or sawdust.

Dwarfs look spectacular when planted in groups.  In alpine regions, they naturally grow that way to provide mutual protection from strong winds.  Only some very early bloomers whose flower buds are susceptible to frost damage need any special protection in garden settings.

In rock gardens, dwarfs need to be lifted and replanted when their roots have filled the available soil space.  Moreover, some thought needs to be given to both irrigation and drainage.  Dwarfs, like all other rhododendrons, require acidic well-drained soil.  They should be planted high, on a slight mound, rather than in a rocky hollow that may allow water to pool around their roots.  On steep slopes, a dam of

mulch or rocks should be placed on the downhill side of the plant so that water is channeled through the roots rather than over the top of the soil.  Regular watering is essential during the summertime in B.C. and a drip irrigation system is ideal both for dwarfs grown in containers and in the field.

In containers, most dwarfs need to be repotted every second year.  During the in between years they appreciate a top dressing of compost.  Feeding with slow-release fertilizer or liquid plant food is also beneficial. 

Minimal pruning is required for dwarf rhododendrons.  Each year, however, it is wise to remove dead branches from under the leaf canopy.  Deadheading is unnecessary for most dwarfs.  However, fussy gardeners may want to remove seed capsules that tend to stick up above the leaves of certain varieties.

Most garden centres carry a very small selection of dwarfs and almost all of these are hybrids.  Only specialty rhoodendron nurseries such as Caron Gardens are able to provide a wide choice of both dwarf species and hybrids.

Examples are:

R. campylogynum (Photo 1) -- flowers come in a wide variety of colours and resemble small bells.

R. cephalanthum (Photo 2) -- aromatic leaves and tubular white or pink flowers.

R. hanceanum (Namum) (Photo 3) -- cream coloured flowers and a compact growth habit.

R. litangense (Photo 4) – purple flowers and tiny leaves that turn bronze in winter.

R. nakaharae (Photo 5) – a creeper with relatively large flowers in various shades of rose and red, blooming into July.

R. saluenense (Photo 6) – bright reddish-purple flowers with foliage that turns a dark burgundy colour in winter.

Among well-respected hybrids are those bred by Warren Berg. Examples are Ginny Gee and Patty Bee, both Superior Plant Award winners, and Wee Bee (Figures 7, 8, and 9).  Any of the Cox bird-name dwarfs such as Ptarmigan (Figure 10) are also worth collecting.  John Waterer’s seven dwarfs, all named after Snow White’s friends, are interesting low-growing shrubs but reach 3 feet or more in ten years.

There are many, many more dwarf rhododendrons that provide a solution for B.C. gardeners who have small lots or who don’t have the time to take care of a large garden.  And the really good news from Peter Cox, the famous rhododendron hybridizer from Glendoick Scotland, is that Canada’s Pacific Coast region is “the nearest to ideal for most dwarfs”.