Dirr’s Encyclopedia of Trees and Shrubs Dirr’s Encyclopedia of Trees and Shrubs MICHAEL A. DIRR TIMBER PRESS Portland · London To Roger Milliken— mentor, friend, and advocate for Noble Trees Frontispiece: Chapel Hill garden, late May 2008. Pages 14–15: Daphniphyllum macropodum Copyright © 2011 by Michael A. Dirr. All rights reserved. All photographs are by the author. Published in 2011 by Timber Press, Inc. The Haseltine Building 2 The Quadrant 133 S.W. Second Avenue, Suite 450 135 Salusbury Road Portland, Oregon 97204-3527 London NW6 6RJ www.timberpress.com www.timberpress.co.uk Printed in China Library of Congress Cataloging-in-Publication Data Dirr, Michael. Dirr’s encyclopedia of trees and shrubs/Michael A. Dirr.— 1st ed. p. cm. Includes indexes. ISBN 978-0-88192-901-0 1. Ornamental trees— Encyclopedias. 2. Ornamental shrubs—Encyclopedias. I. Title. II. Title: Encyclopedia of trees and shrubs. SB435.D57 2011 635.9v7603—dc22 2011007951 Catalog records for this book are available from the British Library. Contents Introduction 7 A–Z Encyclopedia of Trees and Shrubs Abelia 16 Broussonetia 120 Clematis 194 Disanthus 274 Garrya 321 Abeliophyllum 22 Brugmansia 121 Clerodendrum 196 Distylium 274 Gaultheria 322 Abies 22 Brunfelsia 121 Clethra 197 Duranta 276 Gaylussacia 322 Abutilon 28 Buddleia 122 Cleyera 201 Edgeworthia 277 Gelsemium 323 Acacia 29 Buxus 128 Cliftonia 202 Ehretia 278 Genista 324 Acca 30 Calia 132 Cocculus 202 Elaeagnus 279 Ginkgo 326 Acer 30 Callicarpa 132 Colutea 203 Eleutherococcus 283 Gleditsia 327 Actinidia 58 Callistemon 134 Comptonia 204 Elliottia 283 Gordonia 328 Adina 62 Calluna 136 Cornus 204 Elsholtzia 284 Grevillea 330 Aesculus 63 Calocedrus 136 Corokia 224 Emmenopterys 284 Gymnocladus 330 Agarista 72 Calycanthus 139 Corylopsis 224 Enkianthus 285 Halesia 332 Agave 74 Camellia 141 Corylus 227 Epigaea 286 Hamamelis 333 Ailanthus 74 Campsis 144 Cotinus 231 Erica 287 Hebe 339 Akebia 75 Caragana 147 Cotoneaster 234 Eriobotrya 288 Hedera 339 Alangium 76 Carissa 148 Crataegus 240 Erythrina 289 Helianthemum 341 Albizia 76 Carpinus 149 Croton 245 Escallonia 289 Heptacodium 341 Allamanda 78 Carya 152 Cryptomeria 246 Eubotrys 290 Hibiscus 342 Alnus 79 Caryopteris 154 Cunninghamia 248 Eucalyptus 290 Hippophae 345 Amelanchier 82 Cassia 156 =Cupressocyparis Eucommia 291 Holboellia 345 Amorpha 85 Castanea 156 249 Eucryphia 292 Hovenia 346 Ampelopsis 86 Catalpa 158 Cupressus 251 Euonymus 292 Hydrangea 346 Andrachne 87 Ceanothus 160 Cycas 254 Eurya 298 Hypericum 359 Andromeda 87 Cedrus 163 Cyrilla 255 Euscaphis 299 Idesia 363 Antigonon 88 Celastrus 166 Cyrtomium 256 Exochorda 299 Ilex 364 Aralia 88 Celtis 167 Cytisus 256 Fagus 300 Illicium 384 Araucaria 90 Cephalanthus 169 Daboecia 258 Fallopia 303 Indigofera 388 Arbutus 90 Cephalotaxus 170 Danae 259 =Fatshedera 303 Itea 390 Arctostaphylos 92 Cercidiphyllum 172 Daphne 259 Fatsia 305 Ixora 391 Ardisia 92 Cercis 174 Daphniphyllum 264 Ficus 305 Jasminum 392 Aristolochia 94 Chaenomeles 179 Davidia 264 Firmiana 307 Juglans 395 Aronia 95 Chamaecyparis 181 Decaisnea 265 Fontanesia 307 Juniperus 397 Asimina 96 Chamaedaphne 185 Decumaria 266 Forestiera 307 Kadsura 410 Aucuba 97 Chilopsis 186 Desfontainia 266 Forsythia 308 Kalmia 410 Azara 99 Chimonanthus 186 Deutzia 267 Fothergilla 311 Kalopanax 412 Baccharis 99 Chionanthus 187 Dichroa 269 Frangula 312 Kerria 413 Bauhinia 100 =Chitalpa 189 Dicksonia 270 Franklinia 314 Koelreuteria 414 Berberis 101 Choisya 190 Diervilla 270 Fraxinus 315 Kolkwitzia 417 Betula 107 Cinnamomum 191 Diospyros 271 Fuchsia 318 Laburnocytisus 417 Bignonia 118 Cistus 192 Dipelta 272 Galphimia 319 Laburnum 418 Bougainvillea 119 Cladrastis 193 Dirca 273 Gardenia 319 Lagerstroemia 418 5 Lantana 429 Myrtus 519 Photinia 567 Rosmarinus 729 Taxodium 789 Larix 431 Nageia 520 Physocarpus 571 Rostrinucula 730 Taxus 792 Laurus 433 Nandina 520 Picea 573 Rubus 731 Tecoma 797 Lavandula 433 Neillia 523 Picrasma 580 Ruscus 732 Ternstroemia 798 Leiophyllum 434 Nerium 524 Pieris 581 Salix 733 Tetradium 799 Leitneria 435 Neviusia 526 Pinckneya 585 Sambucus 740 Teucrium 800 Leptodermis 435 Nyssa 526 Pinus 585 Santolina 742 Thuja 801 Leptospermum 436 Olea 528 Pistacia 606 Sapindus 743 Thujopsis 805 Lespedeza 437 Orixa 529 Pittosporum 608 Sarcandra 744 Tilia 806 Leucophyllum 438 Osmanthus 530 Planera 609 Sarcococca 744 Toona 812 Leucothoe 439 Ostrya 537 Platanus 610 Sassafras 747 Torreya 813 Leycesteria 441 Oxydendrum 538 Plumbago 612 Schizophragma 748 Trachelospermum Ligustrum 442 Pachysandra 538 Podocarpus 613 Sciadopitys 749 814 Lindera 449 Palms 541 Poliothyrsis 615 Sequoia 749 Triadica 816 Liquidambar 451 Butia 541 Poncirus 616 Sequoiadendron 750 Trochodendron 817 Liriodendron 454 Chamaerops 543 Populus 617 Serissa 752 Tsuga 818 Lithocarpus 456 Livistona 543 Potentilla 621 Sesbania 752 Ulmus 821 Lonicera 457 Phoenix 543 Prinsepia 623 Shepherdia 753 Ungnadia 829 Loropetalum 466 Rhapidophyllum Prunus 624 Sinojackia 753 Vaccinium 830 Lyonia 470 545 Pseudocydonia 651 Skimmia 754 Vernicia 835 Maackia 471 Rhapis 545 Pseudolarix 651 Smilax 755 Viburnum 835 Maclura 472 Sabal 546 Pseudotsuga 652 Sorbaria 755 Vinca 871 Magnolia 472 Serenoa 547 Ptelea 653 Sorbus 756 Vitex 873 Mahonia 496 Syagrus 548 Pterocarya 654 Spiraea 759 Vitis 875 Malus 500 Trachycarpus 548 Pterostyrax 655 Stachyurus 766 Weigela 877 Malvaviscus 507 Washingtonia 549 Punica 656 Staphylea 767 Wisteria 878 Mandevilla 508 Parkinsonia 551 Pyracantha 658 Stephanandra 768 Wollemia 882 Melia 508 Parrotia 551 Pyrus 659 Stewartia 769 Xanthoceras 883 Menispermum 508 Parrotiopsis 555 Quercus 666 Styphnolobium 773 Xanthocyparis 884 Mespilus 510 Parthenocissus 555 Rhamnus 692 Styrax 774 Xanthorhiza 885 Metasequoia 510 Passiflora 558 Rhaphiolepis 693 Sycopsis 777 Yucca 885 Microbiota 512 Paulownia 558 Rhododendron 695 Symphoricarpos 779 Zamia 886 Millettia 512 Paxistima 560 Rhodotypos 711 Symplocos 780 Zanthoxylum 887 Mitchella 512 Persea 561 Rhus 712 Syringa 781 Zelkova 888 Morus 513 Phellodendron 562 Ribes 717 Taiwania 788 Zenobia 891 Musa 515 Philadelphus 563 Robinia 719 Tamarix 789 Ziziphus 892 Myrica 516 Phillyrea 566 Rosa 721 Selecting Plants for Specific Characteristics or Purposes Street and Urban Planting 920 895 Hedging 921 Flower Color 895 Evergreens for Specimens, Groupings, Screens, and Flowering Sequence 900 Groves 921 Fragrant Flowers 904 Weeping or Columnar Habit 922 Fruit 905 Vines for Flowers, Fruit, and Fall Color 923 Fall Color 909 Winter Interest 914 Conversion Table for Metric Measurements 924 Shade Tolerance 915 Hardiness Zones 924 Salt Tolerance 917 Acknowledgments 924 Tolerance to Moist or Wet Soils 918 Index of Botanical Names 925 Tolerance to Dry Soils 918 Index of Common Names 946 6 Introduction Timber Press and I have developed a petition among breeders and intro- Take variegated leaf cultivars of symbiotic relationship in our quest/ ducers who have similar plants. The Abelia =grandiflora, now numbering journey to produce worthy books that financial advantage is often weighted about 17. Many are unstable, produc- gardeners would embrace and enjoy. toward the first mover. Testing and ing green, albino, and other shoot Dirr’s Hardy Trees and Shrubs (1997), t rialing for many woody plants are min- permutations not typical of the origi- Dirr’s Trees and Shrubs for Warm Cli- imal, and marketing supersedes the nal cultivars. I have bred, evaluated, mates (2002), Hydrangeas for Ameri- reality of performance. In this tome, tested, trialed, selected, grown, and can Gardens (2004), and Viburnums I provide the best assessment pos- introduced abelias, and ‘Hopleys’ (2006) have found niches in the gar- sible based on testing data, research (‘Aghop’), rebranded Twist of Lime™, den and nursery circles. This encyclo- reports, performance in nurseries and has been one of the most stable, con- pedia builds on the foundations of the gardens, and evaluations at our breed- sistently true to type. Does this mean Hardy and Warm Climate books, with ing company in Watkinsville, Georgia, that someone else could have a differ- more than 3,500 photographs of spe- Plant Introductions, Inc. (www.plant ent experience? Absolutely! cies and cultivars in 380 genera, with introductions.com). Cross-referencing the Hydrangea an emphasis on the best new intro- ductions of the past ten to 15 years. The garden and nursery worlds have changed dramatically in that time. Independent garden centers have waned, while Home Depot, Lowe’s, Wal-Mart, and other mega-chains command greater percentages of green good sales. Be advised that the mass merchandisers are actively p ursuing new plants to entice custom- ers. Reflecting these advances are the increases in plant patents, which allow the owner to control the licensing of the product. In 1996 (66 years after the Plant Patent Act was instituted), approximately 10,000 plant patents were granted; in 2010, the n umber was over 21,000. This increase reflects the desire of breeders and introducers to protect their intellec- tual property. Also, many plants are not patented, but introduced for the greater good. The new plant tsunami literally swamps horticulturists’ and gardeners’ will and ability to stay current. Lagerstroemia Cherry Dazzle®, a superior red-flowered, genetically The rush to market is based on com- compact selection from the author’s breeding program. 7 paniculata cultivar trials at the Royal garden, and many readers commented watched Knock Out® move around Horticultural Society (www.rhs.org.uk) positively about “seeing” it. the cul-de-sac and throughout the with my Georgia evaluations reflects Unfortunately, the home and gar- neighborhood. dichotomies of results. For example, den in the 2002 book are no more, This garden was spiritually and psy- RHS Trials Bulletin 23 (December as we sold and moved to Chapel Hill, chologically essential to Bonnie’s, my, 2008) evaluated more than half of the North Carolina, for medical reasons, and Susy’s well-being. Susy, who car- more than 80 known cultivars. Best to care for our youngest daughter, ried the gene for cystic fibrosis, was (three stars) were ‘Big Ben’ (lousy in Suzanne. After existing in an apart- blessed to have two double-lung trans- Georgia), ‘Dolly’ (lousy in Georgia), ment for six months (no garden), we plants at UNC-CH and live a rich, full, ‘Kyushu’ (lousy in Georgia), Limelight™ decided to purchase a home, develop vibrant, and meaningful life. We lost (very good in Georgia), Pinky Winky™ a garden, and live a normal life. The our beloved Susy to chronic rejection (poor in Georgia), and so forth. The landscape (initially with bargain-base- in January 2008. take-home lesson: biology is shades ment butterflybushes, abelias, and Books are written on dealing with of gray, and dogmatic acceptance Indian hawthorns—all eliminated) was grief, but Bonnie and I find inner peace of anyone’s results is foolish. Use transformed into a garden with color, with each other and in the garden. these data as guides to the superior fragrance, diversity, and seasonality. Bonnie stated it best—there is joy introductions. In part, it was also a test site for many in nurturing and loving living things “Show me your garden and I shall new plants from our breeding program to their greatest genetic potential. tell you what you are.” This Alfred Aus- and those of colleagues. We sold our place in Chapel Hill and tin quote captures Bonnie’s and my The neighbors noticed, commented, returned to Athens, where in 2009 love of garden-making. As an introduc- queried about the roses (Knock Out®), we purchased a new home on an tion to the Warm Climate book, I textu- dwarf crapemyrtles (Razzle Dazzle® acre and started the garden journey ally and photographically walked the series), and lantanas (Chapel Hill anew. Realizing that planting space reader through our then 23-year-old series), and others. With delight, I was being rapidly consumed, we pur- Hydrangea macrophylla hybrid selections at Plant Introductions, Inc. 8 chased the contiguous lot as well. It was choked with Chinese privet (Ligustrum sinense), kudzu (Pueraria montana var. lobata), and muscadine (Vitis rotundifolia), all quickly cleared; a specimen white oak (Quercus alba), a 50-ft.-high, four-trunked black tupelo (Nyssa sylvatica), and flowering dog- wood (Cornus florida) were preserved. We are enjoying pencil farming this and the home site, dreaming about what may metamorphosize. In autumn 2010, we planted a sinuous shrub border that effectively screens the new lot from the street. Neighbors commented and asked about the identity of the plants. I men- tioned that 14 different viburnums were utilized. They were mystified for, in the South, “viburnum” simply does not resonate. Hopefully, they will enjoy and learn as the border matures. Plant Introductions, Inc., continues to develop. My two partners are Jeff Lantana camara ‘Chapel Hill Yellow’ in production; note flower quantity. Knock Out® roses planted over a French drain between drive and neighbor’s fence, four years after planting: Blushing Knock Out®, ‘Carefree Sunshine’, and Knock Out®, the original red. Chapel Hill, North Carolina. 9