Some Other Plants For Your Garden
Mrs. A. W. (Meldon) Kraxberger, Portland, Oregon
If your garden is mature you will have already solved your planting problems. Any plant you combine with rhododendrons is a companion plant - whether it looks harmonious and is compatible is another matter. A palm tree obviously would be completely out of character because it just doesn't happen in a temperate climate. Compatibility is mainly a matter of soil conditions. The use of lime-loving material such as gray-foliaged shrubs only causes extra work. Labor saving becomes increasingly important today.
There are two kinds of gardens. The kind most wanted is planted for its effect as a whole; the rhododendrons forming the backbone, coming into bloom in blending drifts of color over a long period of time with small trees giving the shade where needed and other good plants supplying off-season bloom and different foliage texture. The other is the collector's garden, where each plant is valued for its possession and successful culture.
In a virgin forest many kinds of plants are combined: small deciduous trees under large conifers, shrubs under and around the trees and on the edge of clearings, and low herbage such as perennials and bulbs, all growing in the area best suited to their individual requirements. This should be the goal in planting a shrub garden, deleting such undesirable items as thistles and brambles.
Presuming you have no forest, some light shading will be necessary for many choice rhododendrons. Planting an early blooming rhododendron on the west side of a large bush can save your bloom on a frosty morning; planting a woodland type rhododendron on the north side of a small tree can save your foliage on a hot summer day. You will probably wish to plant for year-around interest, not easy to accomplish on today's small lots. Rarity of plant material in no way guarantees a lovely garden. There is no substitute for good culture and good growing conditions. Occasionally it is what you do not plant that makes the most effect. Also you can't have it all; that is the purpose of botanic gardens.
Companion plants fall naturally into classes, some fall into two, namely: conifers, small trees, shrubs, groundcovers, bulbs, fall - coloring, berried, winter blooming.
If you desire small conifers, pines look very right. They do provide good windbreak and a certain sort of solidity in appearance. Natural for the west would be Pinus contorta, lodgepole pine, which is easy to grow. In a colder climate Pinus sylvestris, Scotch pine, would be equally good. Both are two-needle pines, thus free from rust. Larix occidentalis, tamarack, is deciduous, has particularly lovely foliage in the spring, bears lots of little cones and grows rapidly. Avoid planting really large timber trees no matter how cute they are when young.
FIG. 9. Stewartia malachodendron notable for its
summer bloom and fall foliage.
Styrax japonica is a very special small tree, lovely in foliage, small and tidy, lovely in bloom, white pendant bells by the thousand in June, and clean. A very good small tree for a shrub bed is Stewartia koreana with lots of single white flowers perched along the branches in June. The foliage is good, coloring nicely in the autumn. This needs shade on its trunk, which can be easily supplied by a rhododendron. Eucryphia nymansay and Franklinia alatamaha are large bushes rather than trees. Eucryphia has evergreen rose-type foliage which colors some in autumn, and single white perfumed flowers in August. It dislikes drought. Franklinia in the west never seems to bloom as it does at home, but it is certainly worth planting for the gorgeous scarlet foliage in October; consider any blooms a bonus. Both of these plants need a warm, but not dry, site. Cornus are excellent for providing shade. The favorites are Cornus nuttalli and Cornus Florida rubra. The western variety needs shade on its trunk. Rather unjustly overlooked is Cornus Florida in its original white form. The horizontal planes of foliage and bloom are much accentuated in the eastern dogwood. Most of these small trees have only white flowers, not a drawback but a peace-making factor in a garden.
All flowering fruit trees are a questionable asset in a planting of rhododendrons. For sheer beauty of flower they are certainly unexcelled, but they are too often grafted three feet above ground level on what no one knows. An ugly bulge at the graft union and a forest of suckers under the tree often result. Also the foliage attracts just about everything that chews all summer long. It need not be this way with a tree grafted at ground level on correct stock, but you will still have to spray. Perhaps an exception should be made for Prunus blirciana, the Japanese plum, because of the very early cloud of rosy bloom, a sure sign of spring. This needs careful pruning of the criss-crossing branches, and treating for aphids.
European birches with their white trunks, most conspicuous in winter, are surface rooting and prone to aphids, which must be controlled for the sake of the rhododendrons. The clump form is distinctive. If you must have this, plant it on the edge rather than within the bed. Liquidambar styraciflua, sweet gum, is also lovely, a little large eventually, but so beautiful in the dark autumn with its blending colors that it is worth considering. Bamboo looks elegant but even the best mannered of the lot, Phyllostachys niger, with its black canes and jade green foliage sprays, needs to be restricted at the roots. In the west the common vine maple, Acer circinatum, a clumpy sort of plant rather than a tree, is popular. Fall coloring is superb. Acer ginnala is hardier with identical effect. Quercus palustris, pin oak, and Quercus coccinea, scarlet oak, are two trees that give good returns. Both are high-colored late in the fall, root deeply, and grow slowly. And you have those oak leaves for mulching.
Magnolias are probably the most spectacular of all. Any of the smaller species or hybrids will perform as you expect, just don't plant rhododendrons too close to the trunk. Magnolia denudata, white goblets open to heaven on bare branches since this one blooms before instead of with the unfolding leaves as do the M. soulangeana hybrids, is choice and to be cherished. Magnolia stellate should not be omitted because it is common. This develops into a large bush with good foliage and starry white blooms from buds of silver fur, nice to watch in late winter as they become plump. If you lose one crop of flowers to bad weather, another soon follows. Magnolia sieboldi is another large bush. This has white cup-shaped flowers that bloom sporadically over a long period in late spring. Scent is heavy. Deciduous magnolias give their all in bloom; fall color is only tawny. For a really hot sunny location, too much so for any rhododendron, Magnolia grandiflora, or any of its smaller varieties like 'St. Mary's,' is supreme. These smaller varieties also bloom when young. The bold foliage, warm golden green and evergreen, is almost unburnable and the large scented ivory flowers in the heat of the summer add interest in the dull season.
FIG. 10. Blossoms of evergreen Magnolia grandiflora
variety 'St. Marys'.
Turning now to shrubs, you will have to be choosy; there are so many available. First to mind come all deciduous azaleas. Because the brilliant colors, gold through tangerine to flame, mostly clash with rhododendrons they look best planted in groups by themselves. There are exceptions: R. schlippenbachii, pure pink; R. albrechtii, too early to clash; pastel selections such as the Exbury 'Cecile' or the Ghent 'Corneille' and the fragrant R. occidentals blend well and add a splash of varied fall color, holding long. Pieris japonica, early in bloom, white bells in drooping racemes, and Kalmia latifolia, late in bloom, pink clusters of open bells, just have to look right. The old evergreen azaleodendron 'Odoratum' likes sun and blooms very late with fragrant orchid flowers. Lucky west coast gardeners have evergreen Ceanothus for a problem hot spot. Ceanothus veitchianus is upright and bushy, needs constant summer pinching to keep it that way, and little water. Bright blue pompons of flowers appear plentifully in June. Every garden needs Daphne just for its perfume. Daphne odora should give you nosegays of pink flowers for your St. Valentine's day table, but only in the mild climates. Daphne mezereum would replace this in colder climates. Osmanthus delavayi, sweet olive, is as heavily laden as Spiraea with small sweet white bells in April. This good-tempered plant becomes a large bush with small toothed bluish green leaves, a different foliage pattern. It repays good care. The loveliest and hardiest Camellias are the English true hybrids. 'J. C. Williams,' pale pink single, 'Mary Christian,' dark pink single, and 'Donation,' rose semi-double, are readily available; others are appearing. They form graceful large bushes with shining foliage, form multiple buds, bloom over a long period, and drop their faded flowers. Almost full sun seems ideal. Camellia japonica grows well enough in the Northwest but, as with hybrid rhododendrons, so many are available that choice becomes largely a matter of personal preference. Camellia sasanqua varieties are regrettably good only on a warm wall, but then very nice in October and November, and perfect for espaliering. Arbutus unedo produces its greenish cream bells in November. To develop the strawberries, two plants propagated from different parents are needed.
There remain five classes of plants to consider. For fall color, vine maple, liquidambar, oak and deciduous azaleas, mentioned before, are paramount. Oxydendron arboreum, so slowly reaching tree stature that it is usually regarded as a shrub, has panicles of white bells in summer; however, its main attraction is the unfailing true red foliage in the fall. If you have something to hide quickly, try common Virginia creeper, Parthenocissus quinquefolia, very good in the fall.
Best of all for coloring are Parrotia persica and Fothergilla monticola, big bushes with hazel-like foliage inconspicuous blooms, both indescribable in their blending of myriad colors, but each different in tone.
Berried shrubs can be spectacular in a park but their value in a small garden is doubtful. Nicer and smaller than English Holly is Ilex pernyi with just as many scarlet berries and more interesting foliage, triangles with spines. Pyracantha with orange or scarlet berries is almost ubiquitous but Pyracantha rogersiana (lava has yellow berries. Pernettya mucronata will supply white or pink berries on low suckering plants. Viburnum davidi seems the only choice for blue fruits. The last two need a pollenizer, which generally gets too big too quick. All of these like an open situation in the sun.
Why not plant something for winter color besides Rhododendron mucronulatum? Use Hamamelis mollis, witch hazel, large bush with exquisite knots of spicy yellow ribbon tied along the bare branches early in the year. These are amazingly frost resistant even in full exposure. Most dependable of all and not the least rare, Jasminum nudiflorum is unfailing in its rent payment. Viburnum bodnantense is fairly new, has clusters of pale pink waxy fragrant flowers most of the winter. It is a joy to own. If I grew any heather it would be Erica carnea 'Springwood Pink'; sun is essential' and group planting recommended as one heather looks lonesome.
FIG. 11. Shortia uniflora var.
grandiflora rosea. A choice
groundcover to accompany
A. W. Kraxberger photos
So now we are down to ground level. The choice becomes ever wider and more personal. We could collect endlessly. Certainly there should be room for Helleborus niger, the so-called Christmas rose, with its white flowers and palmate foliage under one foot. This will even bloom through a snowfall. Ferns look elegant and are quite at home. Any and all Trilliums are happy. Wonderful little bulbs include hardy Cyclamen, especially C. neapolitanum, with its pink or white shuttlecock flowers in autumn, followed by gorgeous mottled leaves that linger until next June; Erythronium revolutum, pink lily-like flowers in spring above mottled foliage, soon gone; Iris reticulate in shades of blue, purple and violet; Galanthus nivalis, old-fashioned snowdrop of most gardener's nostalgic memories; and Muscari, Chionodoxa and Scilla, all three in shades of true blue. All of these will self-seed in a not too tidy garden. Miniature daffodils (there are dozens) are something to collect if you are a Narcissus fan. Plant Daphne cneorum, so long loved, in a sunny spot and Lithospermum prostratum for a patch of brilliant summer blue. Another pet is Gentiana acaulis, ever-widening mats of green in the sun with big royal blue trumpets just above the pads in May. Shortias and Epigaeas, rare and choice, make lovely patches of ground cover in deep shade, but not the kind you walk on. Do not let these become dry. Linnaea borealis you can walk on. Almost any low Vaccinium, Arctostaphylos or gaultheria (please, no salal) form good-looking evergreen mats. Leucothoe keiskei, for deep shade, produces in summer the largest flowers in this genus. True Andromeda polifolia is nice for a sunny damp spot, pink bells and steely blue foliage. All color forms of Daboecia, Irish bell heather, provide flowers in summer and fall; they need sun to bloom well. Primulas of any sort that please you should be contented. Can you imagine a garden with dozens of clumps of Cypripedium reginae, pink and white lady slipper orchid, planted among the rhododendrons? It has been done. A shady area in a rhododendron bed is probably the only place you can succeed with Meconopsis baileyi, the legendary blue poppy of Tibet. A bit taller are the Lilies of Asiatic origin, L. auratum, L. speciosum, their hybrids, and allied species; they like their feet in the shade and tops in the sun. Two to beware of are Convallaria majalis, appealing little lily of the valley, and Vinca minor, periwinkle. Both are just too rampant around choice rhododendrons.
Now you have nice cover for your most precious rhododendrons, some different but not bizarre foliage here and there, an uneven skyline, something for autumn as high-colored as New England, something for the gray winter and all these wonderful little bulbs, but what about that midsummer lull? If flowers are still necessary to you when the thermometer stays in the nineties, try the simple trick of three or five rosebushes, your favorite color, just one variety and beautifully grown of course, with a cool blue Clematis 'Ramona' nearby. And always leave space for one more rhododendron because you will always want just one more.