Winter Protection For Rhododendrons

If you haven't planted your rhododendrons in a protected location, you may have to consider providing them with some winter protection! Rhododendrons, particularly large-leafed forms, are sensitive to winter sun as well as winter winds, and if not protected properly, you may have serious damage or lose the plant by spring.

Damage to plants is likely to happened if the plant did not receive ample moisture before in the Fall. During the winter, drying winds and frozen ground deprives plants of their natural moisture intake. The exposed portions of the leaf...usually the central portion when the leaf was curled...may become brown. This may also appear on the edges of some leaves.

To prevent scorch, plants should be well watered in November, especially if rainfall has been sparse; protected from drying winds; mulched well, and given some shade. New plant growth may not have a sufficient amount of time to become woodsy and harden off for the winter. Also, flower buds are the least cold hardy part of the plant.

Rhododendrons, boxwood, azaleas, hollies, and laurel will benefit from an application of an anti-desiccant, such as Wilt-Pruf. Read and follow all instructions. Spraying should occur in late Fall when temperatures are near 40 degrees F. Most anti-desiccants are composed of a "waxy" substance that can break down during winter's thaws necessitating a reapplication.

If you do not get a change to apply an anti-desiccant, you may want to provide a wind-shield, such as burlap to these shrubs as well as some mulch protection around the base of the shrub. Young plants can be enclosed with chicken wire or dog fencing, and packed loosely with oak leaves. Remove the protection in the spring as buds start expanding. Mature plants can be mulched with several inches of wood chips at the base.

Evergreen boughs can be leaned or tied against plants to limit winter injury. A teepee-like structure constructed with three or four evergreen trees or branches with their points forced into the ground and tips tied together provides adequate protection...or use a burlap covering around individual plants. Snow fencing alone or with a polyethylene plastic sheeting attached to it also gives effective wind protection. Cover the plants just before freeze up in the Fall and uncover after all the frost is out of the ground in the spring.

Weigela...a companion plant

Once the main splash of rhododendrons is over, there is a charming group of plants that fills the color gaps in our landscapes quite nicely. Named after a German botanist, Christian von Weigel, Weigelas are deciduous shrubs of open woodland areas in parts of Asia which have a multitude of foliage and flower features.

Most of our available varieties are selections or hybrids of two species: W. florida and W. praecox, although the wild forms are rarely offered. The blooms, in May and June, are tubular, in small clusters along older stems, often with nicely contrasting stamens. In blossom, they attract hummingbirds by the flock.

The "in" thing these days among plant introducers is purple leaves, starting back with 'Foiliis Purpureis' ('Java Red')...on to 'Victoria', then 'Wine and Roses' ('Alexandra'), 'Ruby Queen', and now 'Midnight Wine'! The color is getting darker, and the plant habit is getting smaller...what's next...a black groundcover Weigela? Attractive and useful plants nevertheless...most of them have pink to bright pink blooms.

The 'Dance Series', developed by Agriculture Canada, have all been selected for very compact habits, extra hardiness, and richly colored blooms. Foliage variations are from green to burgundy, with deep pink or red blooms. Look for 'Tango', 'Polka', 'Samba', 'Rumba' and 'Minuet'.

Gold-leafed forms are a bit more finicky...they need partial shade to avoid foliage burn but too much shade makes them go green so it's a fine line. 'Looymansii Aurea' has pale pink blooms, while the newer 'Briant Rubidor' (aka 'Olympiade' or 'Golden Ruby') has dark ruby flowers that offer a striking contrast. Variegated leaves, with cream to light yellow margins, occur in both species, and have pink flowers. The variegated areas take on rich pink to red tones in fall, for extra punch.

White-flowered forms are available as 'Bristol Snowflake', 'Candida', 'Mont Blanc', and others...but I must admit I don't really care for them...although 'Mont Blanc' is highly rated. Possibly I just haven't seen one at the right stage or in the right setting. A new introduction, 'Carnaval', has blooms of white and two shades of pink all at once on the same plant. That's kind of neat! For deep red, the old 'Bristol Ruby' and 'Eva Rathke', although good and reliable, have been superseded by newer, tidier, non-fading varieties like 'Red Prince', 'Lucifer', and the even smaller 'Nain Rouge'.

Weigelas grow easily in any well-drained moderate soil...and old bloomed-out stems can be cut to the ground to allow new ones to take their place. Trim right after blossoming in the early summer to keep leggy branches in order, and to give time for the wood to ripen and set bloom for next year. Some varieties will bloom off and on throughout the summer, and other appear in early summer and again in early fall.

Two unusual species, W. middendorffiana and W. maximowiczii, have light yellow flowers in late spring...most "un-weigela-like", but truthfully I have not seen either offered for sale locally. Good for you if you can fine one!

Look around in the plant centers when you've gotten all your beddings settled and your rhodos are on the wane...and you'll find one of these to be a delightful addition to your garden...big or small!

Happy Planting!

Two Lovely Ladies

Two of my favourite rhododendrons were named after two ladies - Mary Fleming and the Countess of Haddington. I have no idea what the namesakes of these varieties were like in life, but if I had to guess about them based on the plants bearing their names, then they both must have been lovely ladies, but altogether different.

I picture Mary Fleming as having been a dainty, petite lady who had a spine of steel. She must have been very pretty too. Rhododendron 'Mary Fleming' is such a good "do-er" in the garden. My own plant is in a fairly tough spot that gets full sun for most of the day and is often very dry in the summer. However, Mary Fleming grows well there and rewards me with lots of small pinky-yellow flowers every March. For me, it's one of my most reliable early bloomers and the flowers last through light frosts.

The plant is attractive throughout the year with small leaves that often take on a reddish hue in the winter. It stays fairly small - about 2' in ten years, and that's about the height of mine, but I have seen older plants reach about 5'. It's a hybrid of two lovely species, racemosum and keiski. While my plant is in the ground, Mary Fleming also makes a good potted plant due to its small stature.

The Countess of Haddington is an old variety, (1862), so presumably, was named after the real Countess of the day. It was a cross of ciliatum by dalhousiae. For those lucky enough to garden in warmer climates than mine, I suspect you can manage this one easily out of doors, but here in the Pacific Northwest, the Countess requires effort. I guess that since she's an aristocrat, she expects special treatment.

I grow my 'Countess of Haddington' in a 5 gallon pot. During the summer months she lazes around under the shade of an old apple tree where she gets some protection from the heat of the day and from full sun. I use a slow-release fertilizer treatment three times a year, and the Countess gets lots of water as the pot dries out quickly. I may have to break down and re-pot this plant this summer, but if I do, it will go into as light weight a pot as I can find because I do move the pot around frequently in winter. I occasionally pinch back some of the new shoots to keep the plant a manageable size and maintain some fullness. However, even after 6 years, the plant is a very manageable 4' tall, presumably due to its ciliatum heritage.

Since the Countess of Haddington is tender here, as soon as the temperature drops to near freezing, the plant gets moved to a sheltered area near the house where it spends much of the winter. I like to leave my tender rhodies outside as much as possible in the winter, but I pay close attention to temperature forecasts and my secret to growing them is to be ready to move pots into a frost-free area whenever necessary. The Countess of Haddington is only hardy to about 20F, so I'm prepared to pop it and all my other tender rhodies under my enclosed deck anytime the weather forecast indicates the temperature may drop to more than just a few degrees of frost. There aren't any windows under the deck so the plants remain in the dark during cold weather. During cold weather snaps, I have left them in this location for up to three weeks at a time, but they manage just fine even though there's no light. Once the cold is past though, they get moved back outside to their sheltered spot. I take care to make sure The Countess and her friends are watered on an as needed basis throughout the winter. It is surprising how fast they can dry out, even if it's pouring rain.

As soon as I see the flower buds opening, usually mid to late February, the Countess is moved into my sunroom where I'm rewarded with large, trumpet-like flowers of very pale pink. The fragrance is also wonderful and the plant perfumes the entire house. Since the sunroom is fairly cool, the plant stays in flower for almost a month which makes my efforts worthwhile. So, while Mary Fleming is a tough plant and the Countess of Haddington is a tender aristocrat, they're both lovely ladies, and I enjoy their company.

The Cecil and Molly Smith Garden

Cecil and 'Molly' Smith were the founders and developers of what has become the internationally renowned Cecil and Molly Smith Garden. Cecil started collecting rhododendrons in the late 40s at their first home adjacent to the present-day Garden property near Newberg, OR. Cecil was a grass seed grower by trade...and originally owned much of the surrounding land. He became an early member of the American Rhododendron Society in 1947. In 1951 they obtained the garden property, finished their new house and started the garden. The area had been logged in 1915, but by 1951 had reestablished its growth of Douglas fir and native plants.

Cecil had grown up at Champoeg in the Willamette Valley and treasured the native plants. He also became interested in discovering the best genus Rhododendron had to offer. He eventually helped sponsor expeditions to the Himalayas, and participated in seed exchanges and experimented with hybridizing. His efforts were directed at what he thought were the most outstanding rhododendron characteristics: fine foliage and great flowers. A number of his crosses are found in the trade including, R. 'Noyo Brave' and R. 'Yellow Saucer'.

Cecil was very generous with his plants, sharing his cuttings, seeds, and pollen. He wrote articles for The Bulletin of American Rhododendron Society and his photos were used extensively.

Rhododendrons are the Garden's featured plants! Cecil was among the first to grow R. yakushimanum and used it for hybridizing. He was a "leaf turner" and loved the fine indumentum of R. yakushimanum and R. bureavii. He combined these two species and produced R. 'Cinnamon Bear'...the signature plant in the Garden.

The woodland Garden encompasses about three acres sloping gently to the North. Cecil took advantage of the slope and constructed paths that weave from top to bottom of the property. Decaying logs, tree stumps, and fallen limbs have been retained for their natural beauty. This accumulation of 'duff' provides most of the nutrients required and minimal fertilization is required. The Garden is weeded...because Cecil noted: "Unless a woodland garden is weeded, it is not a garden, but a wild area."

Molly's favorites were the Rhododendron 'Loderi' planted near the house and now are over 20 feet tall. Although never taking much credit for the Garden, Molly Smith contributed upkeep and maintenance in the Garden through the years. When the Smiths lived at the Garden, they freely shared their garden with others and hosted many garden tours. No one interested in rhododendrons was denied a visit in the Garden.

Cecil and Molly each received American Rhododendron Society Bronze Medals from the Portland Chapter, the highest award. Molly humorously commented that no one had ever before received a Bronze Medal for baking cookies! Molly was always the gracious hostess, welcoming her guests to her home and garden with freshly baked cookies. In 1967 Cecil was awarded the Gold Medal and in 1985 the Pioneer Achievement Award from the American Rhododendron Society.

In 1983, after more than thirty years of devoted stewardship, Cecil and Molly Smith reached a point in their lives where they could no longer care for the Garden. The Portland Chapter purchased the Garden when the Smiths made it possible by selling their land to the ARS at half of its appraised value. The Portland Chapter, along with the help of Willamette and Tualatin Chapters assumed its care and management. Cecil died in 1998, and Molly in 2007.

The Smith Garden has charmed and delighted visitors from around the world. Edmund Rothschild and his wife have visited the Garden many times along with other well-known Rhododendron enthusiasts. David Leach, author of Rhododendrons of the World, was a good friend of Cecil's, and enjoyed spending time in the wooded setting. Smith Garden has been featured in Horticulture magazine, and in the PBS television show Victory Garden. It is also included in The American Man's Garden by Rosemary Verey. Locally, every national convention of the American Rhododendron Society and Western Regional conventions held in the Portland area included tours of the Smith Garden. Mike Darcy has highlighted the Garden on his television show. Local newspapers and other publications have also included articles and photos of the Garden.

The native Douglas firs create an ideal environment for a natural woodland garden of rare beauty, featuring superior forms of species and hybrid rhododendrons. Complimenting the rhododendron collection are choice trees, shrubs, wildflowers and bulbs. Each pathway reveals its own visual treat...a moss-covered log with plants tucked in the bark crevices, plants thriving on tree stumps, drifts of wild flowers. Cyclamen, Narcissus, Erythronium and Trillium flourish here. The day-to-day work is done by a small group of volunteers with Fall and Spring work parties of the American Rhododendron Society chapters' members and friends.

Designing a Rhododendron Garden

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.

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 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!

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.

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.
• 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.
• 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.

Fragrant Rhododendron fortunei

Plant hunter Robert Fortune discovered this lovely species in 1855. It is a fragrant rhododendron...but unlike those sweetly scented, tender beauties lindleyi, nuttallii and maddenii, R. fortunei is quite hardy.

Fortune's original collections were made in Chekiang Province, in eastern China, at about 3,000 feet. Other plant hunters later found the species in Anhwei, Kiangsi, and Hunan Provinces growing in woods and forests at 2,000-4,000 feet in elevation. Plant hunter Robert Wilson noted that the species was common on other Chekiang mountains, particularly in the Lu Shan range of the neighboring province of Kiangsi, to the west.

The leaves of R. fortunei are handsome, and show some variation. They are 3 to 7 inches long, 1.5 to 3 inches wide. A prominent and very attractive feature is the deep red of the midrib and petioles (leaf stems); these create a ring of color around the dormant bud that seems to deepen and become more conspicuous in winter. The leaves of the Lu Shan form are typically a dull, olive green in color, and have rich red petioles.

The flowers of R. fortunei are borne in a loose truss of 5 to 12, and are shaped like wide bells...funnel-campanulate. They are pink to pale pinkish-lilac or rose and are fragrant.

R. fortunei flower
Photo by Boris Bauer

R. fortunei has been much used for hybridizing, particularly in North America, and especially in the East...where it is appreciated for its tolerance of summer heat and winter cold. The two great hybridizers, Rothschild and Dexter, made free use of it this rhododendron as a parent. Indeed, one of the most loved hybrids of all time in eastern North America is Dexter's 'Scintillation'.

It is noteworthy that a particularly fine large flowered, sweet-scented R. fortunei clone was used as the seed parent of the original 'Loderi' hybrid grex. The other parent is R. griffithianum; a tender rhododendron found growing in the lower elevations of the Himalayas.

Adapted from Whidbey Island ARS Chapter newsletter, May 2003

 
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