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Great Plant Picks Booklets

Follow these links for PDF versions of the Great Plant Picks booklets:

• 2008
• 2007
• 2006
• 2005
• 2004

Closed Loop Park

The Washington State University Thurston County Master Gardeners maintain demonstration and trial gardens at Closed Loop Park near Olympia. A significant portion of the changing collections are plants being evaluated for Great Plant Picks, such as Sedum (115 species and/or cultivars), Astrantia and Sambucus. Thanks go to Wayne Fagerlund (Evergreen Valley Nursery), Briggs Nursery, Skagit Gardens, and Terra Nova Nurseries for donating plants for these trials. The park is open free to the public; visit the Closed Loop website for directions and hours.

Plant List

In 2005, Great Plant Picks collaborated with the Saving Water Partnership in their Natural Lawn & Garden series of educational booklets. Great Plant Picks helped research The Plant List (PDF file), which contains such useful lists as Wet Winter/Dry Summer Plants, Moisture-Loving Plants, Favorite Pacific Northwest Native Plants and Drought-Tolerant Plants.

Hardiness Zones

The hardiness zones referred to in the Great Plant Picks Fact Sheets are taken from the USDA Plant Hardiness Zone Map. A similar map was produced in Canada in 1967 and it is on the web with a great zoom tool function. While the two zone systems differ, the differences do not come into play in the Great Plant Picks target region: Oregon, Washington and British Columbia, west of the Cascade Mountains and B.C.'s Coast Mountains.
Note that Sunset publications use their own western climate maps and zone system that is entirely different from the USDA system.
We arrive at the zone determination by consulting a number of references and experts and then tempering that consensus with first-hand experience. What will grow well in a Pacific Northwest zone 8 may not always grow well in the zone 8 climate of a more humid region such as the east coast of the US. While we hope that the information we share with the gardening public may be useful to a wider readership, please bear in mind that the information is tailored to the Great Plant Picks target region.
Factors other than weather also affect plant hardiness and performance. Plants grown with too much nitrogen late in the season may have "soft" growth that can be damaged by cold temperatures. Some plants, such as Cercis canadensis, do not get enough heat in summer in the Pacific Northwest to "ripen" their wood and winter dieback can result. Warm autumns that drop suddenly into frigid winters create damage that wouldn't occur with a gradual onset of winter. Snow can insulate plants, while ice can cause severe damage. Plants that require good drainage may perish in the rainier parts of the Great Plant Picks target region as a consequence of winter wet rather than winter cold.
In addition, microclimate plays a role. Is there protection from cold winds? Is hail common in early spring? Is there good airflow that keep frost pockets from forming? Can you plant against a warm wall? What is your soil like? What plants thrive in your neighborhood? Careful observation is one of the successful gardeners best attributes.

Nomenclature

Scientists have recently become able to study the genetic code of an organism with relative ease and low cost. This has led to a better understanding of how living things have evolved and therefore how they are related. The inevitable result is some shuffling of plants from one family or genus to another. In simple terms, some "cousins" have become "siblings" while some family members have moved to a different family entirely. As relationships shift, names change too, as names are our best way of keeping track of relationships.
While we prepare Great Plant Picks educational materials, we often must decide which name to use for a particular plant. Our policy is to use RHS Plant Finder, which is updated annually at the Royal Horticultural Society. The RHS Plant Finder is also available online A major goal of the publication is to provide a nursery directory for plants available in the UK, but its use as a nomenclatural reference is invaluable. We also try to include any synonyms on our fact sheets.

Other References used for Fact Sheets

• American Horticultural Society A-Z Encyclopedia of Garden Plants. C. Brickell and J. Zuk, eds.
• Beales, Peter. Classic Roses.
• Bean, William. Trees & Shrubs Hardy in the British Isles (five volumes)
• Callaway, Dorothy. The World of Magnolias
• Case, Frederick and Roberta. Trilliums
• Combined Rose List. Beverley Dobson and Peter Schneider, eds.
• Ouden, P. den. Manual of Cultivated Conifers
• Dirr, Michael. Manual of Woody Landscape Plants
• Gardiner, Jim. Magnolias. A Gardener's Guide
• Gelderen, D.M. van and J.R.P. van Hoey Smith. Conifers
• Gelderen, D.M. van, P.C. de Jong and H.J. Oterdoom. Maples of the World
• Grant, John A. and Carol L. Trees and Shrubs for the Pacific Northwest Gardens
• Greer, Harold. Greer's Guidebook to Available Rhododendrons
• Hortus Third. Liberty Hyde Bailey Hortorium, eds
• The Hillier Manual of Trees & Shrubs. 6th Edition
• Irish, Mary & Gary. Agaves, Yuccas and Related Plants
• Jacobson, Arthur Lee. North American Landscape Trees
• Jacobson, Arthur Lee. Trees of Seattle. Second Edition.
• Jellito, Leo and Wilhelm Schact. Hardy Herbaceous Perennials
• Krussman, Gerd. Cultivated Broad-leaved Trees and Shrubs and Conifers (four volumes)
• Lloyd, Christopher. Clematis
• Mabberley, D.J. The Plant Book
• Newsholme, Christopher. Willows: the genus Salix
• The Plant Locator Western Region. Susan Hill and Susan Narizny, eds.
• Plants that Merit Attention. The Garden Club of America, eds.
• Pojar, Jim and Andy MacKinnon. Plants of Coastal British Columbia
• Phillips, Roger and Martyn Rix. Perennials
• Rehder, Alfred. Manual of Cultivated Trees and Shrubs
• Rhododendron Handbook: Rhododendron Species in Cultivation. RHS, eds.
• Richards, John. Primula
• Straley, G.B., Trees of Vancouver, UBC Press, 1992
• Thomas, Graham Stuart. Perennial Garden Plants
• Thomas, Graham Stuart. Ornamental Shrubs, Climbers and Bamboos
• Thomas, Graham Stuart. The Graham Stuart Thomas Rose Book
• Vertrees, J. Japanese Maples
• Welch, H. and G. Haddow. The World Checklist of Conifers
• Wyman, D., Trees for American Gardens
• plus innumerable online references