The Use of Color in Rhododendron Plantings
Mrs. Ruth Martin Hansen
The psychological effect of color on the individual must be carefully considered in plant composition or plant arrangement. Certain shrubs such as the rhododendrons, azaleas and flowering trees exceed all herbaceous plants in splendor; therefore they must be grouped in pleasing arrangements so that harmony of leaf, color and form is maintained throughout the entire year.
Plant materials if arranged by their foliage hues in Spring and Fall will give perfect harmony the year around to the planting, but with rhododendrons we must go a step farther and not only consider the foliage, its size, texture and color but the blooms must also be arranged in order that clashes of color may be avoided. It has been stated somewhere that all flower colors may be mingled with impunity, however it is my observation that by the judicious use of a little common sense and color sense that a more attractive arrangement may be had by grouping the colors so that clashes of certain hues may be avoided. A single plant of a rhododendron or azalea or an isolated bed of these plants scattered over the lawn areas are pointless and look most unhappy. They need and demand a background of quiet greenery preferably on the outskirt of a lawn where taller shrubs and trees may be used to give a quiet atmosphere to the planting.
During a normal season R. mucronulatum rose lavender in color inspires quite a warmth of feeling when seen beneath the spidery yellow flowers of Hamamalis mollis, Witch-hazel in the early month of February. Or try planting it in front of Blue Spruce and you have another charming combination. R. 'Praecox' follows closely in order and repeats the yellow and lavender combination when grouped with Corlyopis pauciflora, Winter Hazel which has bright yellow flowers that is a delight to see on any cold February day. R. nobleanum venustum, pink, combined with the single pink Camellia sasanqua, 'Brier Rose' and the double white Camellia sasanqua, 'White Doves' makes a charming planting and color arrangement for a mid-winter planting.
Along in March comes the charming R. 'Cilpinense', a hybrid of R. ciliatum. It has deep pink tubular flowers and makes a pleasing association with the species R. ciliatum, R. leucaspis and R. moupinense, the latter two being planted in the foreground. Speaking of the lovely prostrate R. leucaspis, it is perfectly at home with Hepatica triloba, its whiteness being enhanced by the blue of the Hepatica; or try planting it en masse under R. mucronulatum and a picture of great beauty lies before you. Now comes R. ciliatum, a low-growing bushy plant which is covered with pale pink flowers. This plant makes a fine foreground grouping for many of the larger leaved forms. I particularly like it with R. falconeri as the contrast of leaves makes a most interesting pattern.
Using the species R. lutescens, a clear yellow and R. 'Praecox', a lavender for a background; as the two often overlap their blooming periods, a most pleasant grouping may be worked out by combining R. 'Bo-Peep', a low-growing yellow hybrid, R. 'Tessa', a new lavender hybrid and a plant or two of Erica darleyensis for accent. Corlyopsis spectata may be used in the immediate background to weave this planting of yellows and lavenders into perfect unison. The new large white flowered R. 'Bric-a-brac' surprises everyone with its black stamens. This small leaved hybrid combines in leaf well with the deliciously fragrant May blooming R. 'Fragrantissimum', R. exoniense and R. johnstoneanum thus creating a garden fragrance unsurpassed by any other plant group. Any of the upright growing Crabs such as Malus scheideckeri, M. spectabilis or M. theirfera make a fine compliment for this planting. Another delightful combination for late March and early April is R. 'Dr. Stocker', pure white against R. 'Dame Nellie Melba', deep pink with R. 'Unique', yellow in the foreground offset by Magnolia stellata in the background.
Late March brings out several beautiful red rhododendrons which welcome the Spring with a gorgeous splash of color. For a rich waxy red, the barclayii's 'Helen' and 'Robert Fox' make suitable accent plants. R. thomsonii, a tall growing species cannot be overlooked with its waxy red trusses, but due to its leggy habit of growth it should be used definitely as a background plant. Nor can we overlook R. 'Cornubia' or R. 'Ernest Gill' both beautiful early reds which are a credit to any garden. Another interesting planting may be had by combining the yellow R. 'Diane', R. 'Unique' and R. lutescens together and using the stiffly upright mauve-colored R. desquamatum for accent.
As we advance into the month of April, R. 'Carex Blush', pale pink, is seen to its best advantage when planted beneath the lovely pink Naden Cherry and surrounded by a planting of blue and yellow primroses. This creates a most delightful picture in early Spring. Many fine reds are now coming into bloom and innumerable pleasing combinations can be devised by a graduation of color as they vary from crimson to blood red. A very fine red and white combination can be made by planting R. 'Unknown Warrior' and R. 'Loder's White' together flanked by the evergreen Azalea 'Ward's Ruby'. Pieris floribunda 'Andromedia' may be used for the background.
To me April is the month of the R. Triflorum Series which can change any landscape into a veritable elfin Fairy-land. This group of rhododendrons is invaluable for the intrinsic hues blending from pale lavender, to clear pink, mauve, cream, reddish purple and to an almost true blue color. The flowering Cherries and Crabs blend harmoniously with this group of rhododendrons and should be used generously with them. A planting of the blue R. augustinii against a background of golden Kerria japonica as seen beneath the blush of the Ojochin Cherry makes an unforgettable picture; or try a planting of R. augustinii accented by the dwarf Cytisus kewensis, Kew Broom which is covered with creamy-white flowers and makes a good companion to this rhododendron. The lovely white Mt. Fuji Cherry makes a delightful setting for any of the Yunnanense group. Alba Rosea, another flowering cherry which comes out white then turns cerise as the blossoms age makes an ideal companion for any of the Triflorums. The tree-like Erica Arborea, sending its white spires upward makes a wonderful accent plant in a grouping of pink, lavender and blue yunnanense and augustinii.
Azalea schlippenbachii with its light pink flowers offset in whorls of flat leaves looks like butterflies against the tall conical trusses of the old Dutch hybrid 'Commander'. This old hybrid resembles R. 'Cynthia' in color though not so deep in intensity. Malus floribunda, flowering Crab gives the required lightness and texture of feeling to the planting.
Perhaps one of the loveliest of all the low-growing rhododendrons is R. pemakoense which has unusually large pink flowers for its small size. It makes an ideal ground-cover under such hybrids as the beautiful June blooming R. 'Bonito', or en masse in a Rock garden. Another small grower which is par excellence is R. racemosum, ranging in color from pale pink to deep pink. It likes to be planted in groups. While we are on the subject of small growing rhododendrons a grouping of the Lapponicums cannot be over looked. R. chryseum, yellow; R. russatum, deep purple; R. scintillans, lavender and the delicate pink Kurume azalea, 'Apple Blossom' give a beautiful harmony of colors, not only during their blooming period but also during the Winter months when their foliage turns rich shades of bronze and purple. One of the most delightful associations I have ever seen is the little R. ledoides, pink in color and resembling Daphne odora, combined with the rare blue Daphne genkera. Here is a pleasure rarely seen and never forgotten.
At this time some mention must be made of suitable ground-covers that associate well with rhododendrons. Possibly our Oregon native, Arctostaphylos uva-ursa, Kinnikinnick has no peer whether used under the large growing rhododendrons or rambling over rocks. Another useful native found in the Pine forest of Eastern Oregon is the little leaved Gaulthera humifusa, Wintergreen. This little plant with its round leaves makes a fine companion to R. williamsianum or its hybrids, R. 'Bow Bells', or R. 'Moonstone'. One plant of which I am very fond is Pachistima myrsinites, Mountain Boxwood, another native found at high elevations. Its leaves resemble the Boxwood though much smaller and finer textured. It grows about 18 inches high and makes a good contrast plant in leaf texture for a heavily planted border. The Vaccinium uitis-idea, Lingon Berry associates very well with R. pemakoense and is very colorful in the Fall with its small red fruit. The little gray-leaved Andromedia poliflora nana, 'Andromedia', looking much like a small leaved rhododendron itself is perfectly at home with any of the small leaved group. One of the most effective groundcovers to be planted under rhododendrons or azaleas is the very common Forgetme-not. Here is a piece of blue sky spread upon the ground and easy to maintain by permitting it to reseed itself year after year. It is exceptionally beautiful under orange-colored or salmon colored azaleas. Zauschneria californica, California Fuchsia, a native of Southern Oregon combines very well with R. 'Fabia'. Not blooming until late Summer it seems to carry on the color of R. 'Fabia' in its orange-scarlet tubular flowers and its gray leaves blend with those of R. 'Fabia'. This plant must be planted on a slope to get the full effect of its beauty.
With the month of May the rhododendrons are at the height of their beauty. Possibly one of the most outstanding of all rhododendron hybrids is the wonderful group of the Loderi which include 'Loderi King George', 'Loderi Venus' and 'Pink Diamond' to name only three of this remarkable group. These plants all require part shade and adapt themselves to woodland settings. If one has the space, a combination of Betula papyrifera, Paper Birch grouped before Tsuga heterophylla, Western Hemlock and flanked by Cornus nuttalli, Pacific Dogwood and Malus parkmanii the Parkmanii Crab makes a most interesting and beautiful background for the Loderi or any of the large growing types such as R. 'Beauty of Littleworth', R. 'Faggetters Favorite' or R. 'Susan'. The foreground may be planted with a group of Pinus mughus with perhaps a plant or two of Astilbe japonica. In such a setting our native Aruncus sylvester, Goats Beard may be used to excellent advantage by accenting the planting with its long creamy-white plumes. If one cannot afford the luxury of space for such a planting, the flowering Cherries or Crabs planted in front of Chamaecyparis obtusa, Hinoki Cypress or Chamaeeyparis lawsoniana Wisseli will give a similar effect on a smaller scale.
A few other pleasing combinations blooming at this time are R. 'Mother of Pearl', white, flanked by R. 'Van Nes Sensation', pale lilac with R. 'Goldsworth Pink' and two or three plants of Azaleaoides fragrans, lilac in the foreground with Magnolia hypoleuca in the background. Or try 'Mrs. E. C. Sterling', R. 'Betty Wormald' and R. 'Van Nes Sensation' together with Kalmia latifolia and some of the pink Kurume azaleas in the foreground with Clematis montana on a wall forming a background for this pink and lilac combination.
The orange shades of rhododendrons look particularly well when planted under Prunus bliriana, Prunus pissardi or the red Japanese maples. Try R. 'Souvenir of W. C. Slocock' or the Fabias in this location and for accent add a plant or two of the electric blue Anchusa myosotidiflora, Chinese Forget-me-not. Another pleasing combination is a planting of the species R. griersonianum under Prunus bliriana, the geranium red of this species seems to blend the two plants together in harmonious unison. I am very fond of a mass planting of the species R. griersonianum and its hybrids, such as R. 'Fusilier', R. 'Tally-Ho', R. 'May Day', R. 'Day Dream' and the Fabias all grouped together. This creates a sequence of hues blending from geranium red through the orange-red shades and creates a wonderful color gradation.
The beautiful R. 'Blue Peter', R. 'Sapho', white with blotch and R. 'Marchioness of Lansdowne', pink with blotch look very well together when planted beneath Laburnum vulgare, Golden-Chain tree. For a really startling combination try the deep red R. 'Mars' with R. 'Purple Splendor' flanked by the yellow R. 'Lady Primrose' or the Azaleodendron 'Broughtonii Aureum'. This boisterous association is most striking but one must use it with great care. A lovely purple and white combination can be worked out by using R. 'Purple Splendor', R. 'Loder's White' and 'Mrs. J. G. Millais' together.
For an unusual planting of salmon colors try R. 'Azor', 'Diva', 'Azma', and 'Sarita Loderi' all in one grouping with Magnolia sieboldii in the background and white Foxgloves judiciously spaced throughout the planting. Speaking of Foxgloves, the common purple ones blend in beautifully with R. 'Fastuosum Flore Pleno' or the R. ponticums, A few of these biennials planted among your rhododendrons will create a woodsy atmosphere whether in a small city garden or a large country estate.
In closing I wish to say that the enormity of this subject on Color with Rhododendrons may readily be understood by all who grow these plants. This article is little more than a suggestion of the many harmonious possibilities in rhododendron plantings as observed by myself. To name a few of the many delightful color combinations is all one can give in a short space. However, I reiterate that for harmonious groupings one must choose plants that either agree or contrast well together in color and foliage texture; thus a simple harmony may be attained throughout the entire year.