Naturalizing Bulbs for the Shade and Woodland Garden

Transcription

1 Naturalizing Bulbs for the Shade and Woodland Garden Bulbs fill a unique and fascinating niche in the horticultural world. Of all the flowering perennials, they have one of the shortest bloom times relative to their annual cycle; or, if you want to look at it another way, one of the longest dormant times. The reason for this is simple. These perennials evolved in the more fertile margins of extreme growing conditions. Unpredictable climatic patterns forced them to evolve some form of extra food and water storage systems, in addition to what is provided by Mother Nature through leaves and roots, to help them survive from one year to the next. These conditions also forced bulbs to evolve two ways of reproducing: by setting seed like other flower-bearing plants, and by cloning new bulbs to spread the clump in good years, and to replace the original bulbs as they aged and died out. Bulbs, in the strictest botanical sense, are actually one of five underground storage organs: the true bulb (e.g. Muscari), corms (e.g. Crocus), tubers (e.g. Begonia), rhizomes (e.g. Iris), and tuberous root (e.g. Dahlia). Horticulturists and gardeners use the generic term "bulb" to refer to all of the above. Their long dormancy as well as their two-fold reproduction system makes bulbs a very useful garden addition. Their perennial habit provides the gardener low maintenance options. Their reproduction method makes for easily controllable spreading. Their ability to thrive in conditions of heat, swampiness, shade or drought allows them to fill spots in the garden where other plants cannot flourish, enriching us with interesting foliage, florescence and aromas. Naturalizing bulbs have the following characteristics: - They are low-maintenance, usually needing, at most, a bi-annual feeding and mulch. Many need no extra care once established. In the correct spot, they thrive without help. - They spread to form drifts of blooms or low mats of colour in otherwise problem areas: under trees, on rocky hummocks, along dry margins, or in deep shade. -They are sometimes called "species" bulbs, identifying them as the original, wild form of the bulb or descendents of a very early cultivar that reproduces true to form. - Whether the wild species bulb, or a cultivar, they have bloom features that retain some important aspects of the wild parents' characteristics, like earlier- (crocus) or later-season blooms (tiger lilies) than the hybrids, wonderful perfume (narcissus), blooms with unusual patterns and colours (fritillaries). -They are usually long-lived, or if short-lived, readily clone young bulbs from the original. -They are often smaller specimens than the newer, larger, showier, cultivars of the same genus or species. -They are usually more pest and disease resistant and their hybrid cousins. - They often flourish in a wider range of conditions than their hybrid offspring Basic Design Many gardens are designed to be viewed from only one or two angles (the road, the house). A woodland garden with its protected seating areas, winding pathways, dappled light and central lawn or meadow is meant to be viewed from within, and up close. The woodland garden has tall trees, called the canopy (sometimes a high fence back drop covered in vines where no large trees are practical), some mid-sized shrubs in front of and partially under the canopy, shorter perennial and annual beds around a central lawn or meadow, protected sitting places (sometimes called "outdoor rooms"), often a gazebo, or a small pond. So, when looked at from a design perspective, an urban back yard can make the perfect low maintenance small woodland garden. Add an entrance pergola to your yard, a winding pathway of foot-deep chips through the center or around one side. On the other side, create bit of height variation with a couple yards of cheap rock rubble planted with ground cover, and you have the basic structure of the classic woodland garden landscape. Now add bulbs! Woodland bulbs offer small blooms along a short path leading to the gazebo or bench under that maple tree in the back corner of the yard. They surprise us as stately specimens punctuating a shady, two-foot wide bed of

2 mid-sized shrubs and vines, or capture the eye with contrasting form and colour next to the Hosta and Astilbe. They form a carpet of colour under an evergreen or multi-trunked small deciduous trees. On that too-dry grassy area at the top of the yard, bulbs needing drought summer months turn a trouble spot into a Mediterranean rockery bed with interesting large stones and statuary. In a season or two you can easily transform a boring yard into an intricate feast for the senses that is not only easy to create, but far less work to maintain than most of your neighbours' efforts. Woodland gardens are generally designed to remain as low-maintenance as possible, so the following lists do not include bulbs that may be very large and showy but are high-maintenance short-lived hybrids or those susceptible to pests. Squirrels and raccoons will sometimes predate our flowers. Of course, deer will browse to death just about anything except narcissus, and love the new growth and stalks on most spring bulbs, so protect these or make them inaccessible if you have these common pests. Some bulbs, like tulips (a bloom that is a deer favourite) are included where they are mostly the shorter species types, which tolerate a bit of shade and do not offer nice long juicy stalks and blooms, so will often be overlooked by deer as there are other tastier morsels to munch. Be advised, though, the only ones who never read the deer-proof lists are the deer. Spring-planted versus autumn-planted bulbs The main bulb-buying season is autumn. These bulbs are planted in late summer to early fall, and reward us with some of the earliest garden blooms, often as soon as the first warmth of the new season begins in late winter. Many need the autumn to settle in their roots and plump up. The exception are the autumn crocus and leucojum: these are bought in early autumn, are planted immediately, and bloom about a month later. Many autumn-planted bulbs want a good cold spell to do well. These are noted, as well as the varieties that survive warm winters, but whose cousins need cold. Spring-planted bulbs are bought early in the year and planted once the soil is warm, usually mid-spring. They bloom from early summer through mid-fall. Many, like canna lilies and some dahlias and gladioli are not hardy, and must be lifted (in the colder zones), and brought inside then re-planted the next spring. Again, only the hardier, shade tolerant varieties of the genus are listed. Sun versus Shade The majority of bulbs are sun-lovers, and need full sun (6 hours) to remain healthy. Remember, though, there are many varieties that are not troubled by the roots of deciduous trees and bloom before the trees have leaves, giving them enough sun during their bloom season. By the time the tree leafs out and becomes the focal point, the lovely mat of colour that is the early spring bulb, is finished for the year. Other bulbs needs summer drought during their summer dormancy. Again, these bulbs can be added to the woodland list when carefully positioned. Tip: To encourage naturalizing, always allow the seed head to develop, and never cut stalks and leaves until they are completely yellow and wilted. This encourages the bulb to clone baby bulbs, and in some species, self-sow by seed as well (e.g., bluebells). Tip: When planning a naturalizing group, plant the bulbs in uneven numbers and irregular patterns. If you are buying bulbs over several seasons, and/or for a large area, spread the bulbs sparsely throughout the area. Let the bulbs fill in the spaces naturally. This keeps the effect natural-looking, and allows each bulb room to increase. It will also tell you if part of the area is marginal, unsuitable, or has a pest. The rest of the area will thrive, and you can make better choices or remove the pest without losing the whole group. If you decide to add different varieties in coming years, you can easily fit them into the scheme; the newcomers will look as if they have been there all along. Tip: Bulbs are usually planted in the soil to a depth that is twice their height. In other words, the top of the bulb

3 should be as deep in the soil as its own height. Most bulbs will die if planted upside down, but with some bulbs, like anemone, it is difficult to tell the top from the bottom. If you are unsure, plant the bulb on its side (at the correct depth). The stem will easily turn the corner and find the sun. Bulbs by Season Only three seasons are listed, although, technically, there are bulbs that bloom in winter, that is in the early part of the year before March 21 st. Some spring planted bulbs last well into November, and sometimes early December, a time we think of as winter but is actually late autumn. So, to simplify matters, all very early and very late bulbs are listed in either spring or autumn. SPRING: Arum italicum. This is actually a three-season plant, and is a true shade lover. At over 3 feet it is a large plant, and a unique specimen in the shade garden. The leaves sprout in late autumn or early winter maturing at about a foot long on a stem of approximately the same length. White flowers (called spathes) appear in spring, and last through summer. The leaves die back in summer, leaving elongated clusters of red fruit until early to mid autumn. Anemone species. These early bloomers are cold tolerant, and need a good annual chill for continuing performance. They are perfect under trees in the woodland, quickly forming a carpet of colour before the trees green up. They also do well in a meadow setting. - A. blanda blooms in early-to mid season. Vivid blue compliments the whites and yellows of late crocus and short species tulips, or naturalized in short grass. - A. apennina appears several weeks after blanda, and is usually sky blue, though white and pink are also available. - A. nemorosa the small, white, woodland anemone, needs cool conditions and constant moisture. In acid soil rich in humus, these little gems spread rapidly. They cannot tolerate dry soil, so planting near or under pine or spruce trees is not recommended. - Chionodoxa luciliae. In its native Greece, this little flower blooms at the edges of the mountain snow banks. It blossoms are deep blue through pink to white. Great under deciduous shrubs where sun hits ground in early season, and equally good in rockery or along pathways. Does well in both full sun and partial shade. Crocus species. You'll get smaller blooms than those of the big Dutch hybrids but more from each corm, and a longer-lived plant that has time to naturalize. - C. ancyrensis very early yellow - C. biflorus the familiar lilac or blue & white striped blossom - C. chrysanthus the true species type is yellow-orange, and scented. There are several selections here, with many named varieties in yellows and blues.c. 'Snow Bunting' is highly recommended by many horticulturists. - C. tommasinianus most prolific, and easiest to grow, it is violet or purple in mid-season. It will soon make a carpet of blooms. Space the corms over the whole area you wish to cover, and it will fill in. Convallaria majalis. Lily-of-the-valley is highly scented, spreading, and long-lived. It MUST have shade, damp and mulch all year. Try it under Aucuba japonica in deep shade. Often an expensive tuber, it is, however, very long-lived, and will spread readily. Corydalis solida. This is a spreading ground cover with fern-like foliage that offers rows of purple blossoms along the flower stem. Some varieties are red. Good in light shade foreground as tall cover, or spreading over walls and through rockery. A wonderful companion to ferns. Cyclamen repandum. This crimson flowered species one of the exceptions among a genus known for autumn flowers. See the genus description under the autumn listing.

4 Eranthis hyemalis. This is the popular winter aconite, a very early, bright yellow bloomer. It is good in rock gardens and under-plantings where the sun hits in spring then becomes shady for the rest of the year. Good combined with later blooming bulbs like crocus, narcissus, etc. Choose an area that never completely dries out or (if the tubers survive at all) you will never get a good carpet effect over the years. Erythronium species. This group of plants sports small blooms on 6 10 inch stalks. Their recurved, nodding habit shows their membership in the lily family. They are happy in the shade on the spongy, moist woodland floor. They are some of the most charming, and easiest to grow of the woodland flowers. The Pacific Coast is home to several natives that are offered in local garden centres. -E. tuolumnense cultivars 'Kondo' and 'Pagoda' both bloom in shades of yellow, are vigorous and easy to obtain. - E. oregonum a larger species with creamy white flowers. - E. americanum the yellow trout lily does well in colder areas, hardy to Zone 4 - E. dens-canis the European dogtooth violet bears pink, white or lilac flowers only 1 ½ inches across. - E. albidum the North American dogtooth violet has blooms that are almost a foot tall, and also does well in colder areas, hardy to Zone 4. Fritillaria species. This is a varied genus whose members can have quite different needs. The woodland group does best in moisture retentive, humus rich soil, and needs cool summer climates. Fritillaries are recognized by strangely marked flowers. - F. camschatcensis the chocolate lily bears dark purple-black pendant flowers grouped on 5 inch stems. - F. meleagris the foot-tall checkered lily does indeed have checkered blooms of deep pink and white. - F. affinis is taller than meleagris (up to 2 feet) and has flowers that are greenish white with purple speckles. - F. uva-vulpis (pictured) is short (8 inches) and understated, so is good near a walkway where its dark brownish purple, pendant bells can be enjoyed up close. Galanthus species. Shy, nodding snow drops are among our earliest spring flowers. Their bright white elongated bells are great with crocus, or beneath taller fritillaries. They are native to colder climates, and want at least some winter nights that drop below freezing to maintain vigour. - G. elwesii blooms are heavily infused with green and more egg shaped, and is adapted to more mild winters. Hyacinthoides species (formerly, Scilla, then Endymion). These are the bluebells. - H. hispanica the Spanish bluebell, and - H. non-scripta the English bluebell, are mainstays of the shady, damp garden. The Spanish bluebell is taller (about 20 inches) with erect stalks, whereas the English bluebell is 12 inches, arching, and fragrant. Both species are available in blue, white, and pink. They cross-breed readily when planted near to each other, and hybrids appear. Ipheion uniflorum. These charming little six-petaled flowers need regular water during their bloom time, but prefer dry summer dormancy, accepting water only where the drainage is good. This makes them great choices for naturalizing in the grass on a partly shaded slope that dries out in summer, or on a rocky hummock. Leucojum species. These are similar in appearance to galanthus but bloom later in the season, and continue well into summer. Most in this genus want sun, but the following species need bright light, but very little direct sunshine. Grow them in humus rich soil that stays damp. They thrive near water. - L. vernum the 'spring snowflake' gives us green-tipped nodding bells on 12 inch stems.

5 - L. aestivum the 16 inch 'summer snowflake' actually begins blooming in spring, and has chocolate-scented white flowers. Muscari species. The Grape hyacinth. The 6 to 8 inch stalks of grape-coloured spheres are the trademark of these vigorous, easy care bulbs. The strap-like leaves often appear in autumn to stand over winter, and the blooms appear in mid-spring. They spread readily and some can actually become invasive, especially M. armeniacum, which will also self-sow from seed. There are many cultivars to choose from, each offering a range of blossoms in blues through purples. -M. botryoides the 'common grape hyacinth' is the best behaved. It is sometimes planted along shallow swales where it gives the effect of an undulating stream. -M. botryoides v. album has slender stalks of fragrant, white flowers. Narcissus species. Narcissus is considered one of the most versatile and durable garden flowers. A varied genus, it has 12 separate divisions. This genus needs more sun than common knowledge has it, or the bulbs become diseased and die off quickly. Make sure that during bloom-time there is at least 3 hours of mid-day sun. All divisions can be planted under deciduous trees, as long as the drainage is good and summer moisture minimal. If planting in the high shade of not-yet-leafy deciduous trees, choose a tree with taproots as ones with shallow fibrous roots will interfere with the bulbs. The small and dwarf narcissus do well naturalized in meadows or grass that is not watered in the dry season. Puschkinia scilloides these blue-striped white flowers appear on their stalks about the same time as their relatives, Chionodoxa and Scilla. The three can form a lovely companion group of flowers. Puschkinia do best in partial shade, are the hardiest of the bluebell-type flowers (to Zone 3), and naturalize freely. Simply plant them early in the fall so they have ample time to root before winter, and make sure they do not dry out in summer, as they like moisture retentive soil all year. Scilla species. This group is hardy and reliable. They do well in areas that are sunny early in the season, then become shady as summer arrives. They are sometimes confused with bluebells, but can be recognized by star shaped blooms that hold themselves more upright than the bluebell. -S. bifolia this is the earliest flowering species; it naturalizes very well. Its blooms are commonly mid-blue, but there are also pink and white varieties. -S. siberica the best known of the scilla, and the most hardy (Zones 1 8), produces a deep, true-blue blossom. Tulipa species. As a rule, tulips need sun and a winter freeze to maintain vigour. The earlier, much smaller and shorter non-hybrid 'species' tulips, though, can be planted under deciduous trees or at the margins of sunny pathways. Though smaller, these tulips blooms are no less beautiful and unique. -T. kaufmanniana (pictured) this is the lily-flowered tulip. Creamy yellow blooms have a red stripe on the back, and open flat in the sun. -T. pulchella this one stays close to the ground at only 4 inches, and produces vibrant purplish pink or hot pink blooms as early as February if it gets a good winter chill and equally good drainage. -T. saxatilis not only is this species tolerant of warmer winters, its deep yellowcentered lilac blossoms are scented. -T. bakeri this species' blossoms are similar to saxatilis but are appear in clusters rather than singly. It also tolerates warmer winters, blooming mid season. -T. sylvestris this late bloomer with yellow blossoms is the third in the group that tolerates a mild winter. SUMMER The list of naturalizing bulbs for summer is much shorter than the Springtime offerings. Many summer bulbs are in the spring-planted group, and are either too tender, or are sun- and drought-lovers (either summer or

6 winter), for the easy care shade or woodland setting. The following are the exceptions, so are well-suited to the woodland setting. Arisaema species. These unusual shade lovers are related to the calla lily, with flowers of a similar form. All have similar leaves and blooms, but are different heights. They are striking conversation pieces to patio, shaded deck or at a pathway junction. -A. speciosum the cobra lily, produces a purple, mottle leafstalk with a 2-3 foot stem topped by an 8-inch purple and white spathe. - A. sikokianum the Japanese species is the smallest. - A. triphyllum also called Jack-in-the-pulpit, is native to Eastern woodlands of North America. Cardiocrinum giganteum. The Himalyan lily needs filtered sun or light shade to be happy, and does well in our climate as long as it gets summer moisture and no hard freeze. In July and August it produces huge white flowers with red markings. It can be slow to establish, but once settled in, becomes a spectacular 9 foot- giant. Cyclamen purpurascens. This nearly evergreen species has fragrant blooms and red-backed leaves lined in silver. Like C. repandum it is one the exceptions among a genus known for autumn flowers. See the genus description under the autumn listing. Lilium species. Modern hybrid lilies do not do well in a woodland setting. The North American and Martagon species, however, are quite at home in dappled or partial shade. Plant on mounds of leafy, gritty well drained soil that stays evenly moist, and with a minimum of 2 hours of sun a day. They add a unique dimension to our shade gardens and reward our efforts with spots of colour floating above the woodland floor. Although most of the species lilies are difficult to find, and difficult to establish, a few are recommended for the easy care garden: -L. superbum the turkscap lily is by far the easiest to grow. This lily's blooms are orange to magenta with purple or brown speckles. The recurved, nodding flowers appear July through August. -L. martagon another turkscap from Mongolia of similar colour to superbum also offers a white variety (var. album). Zantedeschia species. There are two calla lilies that do well in our climate. -Z. aethiopica it is the earlier bloomer, evergreen in a protected spot, and will often bloom in late spring then continue through summer. It does best in moisture-retentive soil that remains so all year, especially at a pond or stream margin in light shade to full sun. -Z. elliottiana the golden calla has blooms that begin as green-rimmed white then mature to a deep yellow. AUTUMN Colchicum species. The autumn crocus, also called meadow saffron, blooms from September through October on bare stems, and offers greenery in spring that dies back in summer. There are several hybrids to choose from for coloured blossoms. It looks best when naturalized along paths or walkways. Although saffron will tolerate a wide range of soils, it does need reliable drainage, with some moisture all year. It does not like warm winters, so be sure to plant it where it will get a nip of frost or it will not truly naturalize. -C. autumnale this species is the quickest to naturalize. There are pink and white flowered cultivars to choose from. The blossoms do not stand up well to wind and rain, so plant it in a sheltered spot. -C. speciosum has the largest and most weather resistant blooms. It is also the earliest, offering large pinkish lavender, chalice-shaped blooms. Crocus species. Shaped like their springtime cousins, these crocus give us blooms in autumn, and greens only in Spring. - C. cartwrightianus -C. pulchellus -C. sativus (saffron) C. tournefortii all are available right at the beginning of the autumn buying season, and should be planted

7 immediately. Within a month, they bloom. Cyclamen species. The hardy cyclamen are very satisfying shade plants for flower and foliage. As long as there is plenty of leaf mould to feed them they grow very well under deciduous trees, tall shrubs, or on a shaded scree or rockery. Hardy cyclamen need an alkaline environment many woodlands do not have, but if the ground is acidic this can be easily corrected by adding over top of the compost at least two inches of #1 turkey grit, a type of calcium-rich gravel found in feed stores. All cyclamen self-sow, so let the seed pods develop and drop around the parent plant. When new ones emerge you can let them increase to form a ground cover, or move some to another location. Note: this is not the florist's cyclamen, a strictly indoor plant that will not endure frost. - C. coum the hardiest and most reliable of the cyclamen, it often blooms all winter. -C. hederafolium its ivy shaped foliage is marbled with white and silver, and is the earlier bloomer. Leucojum autumnale. Like its spring-flowering cousins, this bulb has nodding white flowers. Instead of the green spotted tips, it has a red-tinged base. See the spring group for cultivation needs. Tricyrtis species. The toad lily is very happy in deep or partial shade, but needs humus rich soil to thrive. It blooms from early to late autumn on slender but sturdy stalk up to 32 inches high. -T. formosana from early through late autumn it blooms in pink or magenta speckled stars. -T. hirta this Japanese native will often begin blooming in late summer, but lasts through autumn. It has funnel shaped, purple spotted white flowers. How to shop for bulbs The rule of thumb is: clean, hard, and heavy. Clean: the outer cover should be free of mould or rot, and look plump and clean, even when it is a gnarled tuber or hairy corm. Heavy: a healthy bulb feels heavy for its size. Hard: any bulb that is squishy or soft is dying, dead, or diseased. Bulb Fertilizers Traditionally, a handful of bone meal was thrown into the bottom of the hole when a bulb was planted in the autumn. Recent studies show that this is not a good practise, and can actually burn the bulb. Until the bulb is fully established, a bit of fertilizer helps it settle in. The best fertilizer for most flowering bulbs has an N-P-K ratio of It can be also be mixed half and half with bone meal or rock phosphate, and scratched into the top 2 inches of the soil, where rain and composting will let it trickle down to be used by the bulb as needed. This mix should be applied twice a year to young plantings: first, when the bulb is planted in early autumn or when the leaves first emerge in spring, then again at the end of the blooming cycle. Tulipa (a genus that usually needs fertilizer for its whole life or it declines quickly) benefits from a ratio. If mixing your own tulip fertilizer, equal parts of blood meal, bone meal and green sand has this profile and is recommended by some bulb specialists. Sources Bulbs for All Seasons, Edinger, Lang, Sunset Publishing, Menlo Park CA, Lois Hole's Favorite Bulbs, Hole's Publishing, St. Albert, Alberta, Canada, A-Z Encyclopedia of Garden Plants, Canadian Edition, eds., Brikell, Roles, and Cole, Dorling Kindersley, Ltd, Toronto ON, Canada, The Woodland Garden: Planting in Harmony with Nature, Forster & Downie, Raincoast Books, Vancouver, BC, Gardening With Native Wildflowers, Jones, Jr., Foote, Timber Press, Portland, Oregon, 1999 The New Flower Expert, Millennium Edition, Hessayon, Transworld Pubishers, London, UK, J. Canning, 2010