Dirty fingernails are not the only requirement for growing plants. One must be as willing to study as to dig, for a knowledge of plants is acquired as much from books as from experience.— Elizabeth Lawrence

Gardening is America's number-one leisure activity, enjoyed by one in three adults. Why do we garden? Survey responses suggest we like being active and out of doors, we garden to relax, and we find creative expression in the "slowest of the performing arts." While this hobby needn't be expensive, Americans collectively spend $30 billion a year on their lawns and gardens.

In the Pennsylvania Horticultural Society's McLean Library, we work with amateur gardeners who want to learn the art and science of horticulture. Like similar libraries, we answer thousands of garden-related inquiries each year. As is true of all libraries, we routinely use and recommend informative Web sites.

This article's Web resource list is not exhaustive. There are too many gardening sites to note every good one. Instead, I've limited this article to resources we've used or recommended to gardeners. The sites are mostly in the U.S, with a nod to Canada and the U.K.

These resources are for gardeners. Related topics, such as botany, plant sciences, and landscape architecture, deserve separate treatments, so we did not include them.
 

Gardening Is Regional
The Web is global but growing conditions are local, subject to variations of soil, temperature, light, and water. How do gardeners know which plants will grow in their back yards? To begin, they must understand "hardiness," a plant's likelihood of surviving winter's cold or summer's heat. Hardiness zones are "climactic zones established for the purpose of classifying plant hardiness" (Complete Gardener's Dictionary, Barron's 2000). Gardeners consult hardiness zone maps to verify which plants can live in their garden. The most commonly used U.S. map is the U.S. Department of Agriculture's Hardiness Zone map, which divides North America into 11 zones, with zone 1 in the north and zone 11 in the most tropical climes. A map sits on the U.S. National Arboretum's site at http://www.ars-grin.gov/ars/Beltsville/na/hardzone/ushzmap.html. Agriculture Canada publishes a Canadian zone map at http://map1.agr.ca/scripts/esrimap.dll?name=Plant&Cmd=Map&Lang=En.
 

The Naming of Plants
Like all living things, plants have "official" Latin names and common names. Common names often cause confusion. A Lenten Rose is not a rose by any other name at all — it's a hellebore (Helleborous orientalis). So if you want to grow a Lenten Rose, it's futile to consult a rose book or Web site. Let's say you visit a nursery to buy a Cedar. Do you mean an Atlas Cedar (Cedrus atlantica)? Or a White Cedar (Thuja occidentalis)? When in doubt, cross-check a common name with its Latin name and read the plant description carefully. Latin names are harder to spell than colloquial names, so when you search the Web with Latin names, have a good horticultural (printed) reference handy if you can, such as D. J. Mabberley's The Plant-Book (Cambridge University Press, 1997).
 

Gardening Niches
Gardeners' interests can be described two ways: what they grow and where they garden. Many gardeners have plant passions, such as herbaceous perennials or native plants. Some specialize in one plant — roses, orchids, or rhododendrons, for example. Plant societies, whose members are knowledgeable hobbyists, foster the growing, collecting, swapping, or sale of prized plants. Many plant societies have informative Web sites. Where gardeners garden is equally diverse: on city rooftops, in containers, or indoors; on country estates, deserts, or by the seashore. Some garden alone; others like the camaraderie of community gardening.
 

What Do Gardeners Want?
What information do gardeners seek? Our reference logs reflect their most common concerns:

• Diagnostic — something is wrong with a plant. Need to identify pests, diseases, environmental situations, and recommend solutions.
• Plant identification — what plant is this?
• Right plant, right place — gardener needs plants appropriate for situation, i.e., shade plants or seashore plants or plants for slopes, etc.
• Cultivation information — how to grow, care for, and propagate the plant.
• Where to buy plants — especially ones not locally or easily available.
• Garden travel — which gardens to visit and best time to visit.
• Where to learn more — where to take classes, attend lectures, join a plant society; book recommendations; Web site recommendations.
• How to research historic landscapes — user needs period garden designs and plants.

In our Internet classes on gardening resources we emphasize that most reliable plant and garden information still exists in print form. Web resources are merely one part of horticultural information.
 

Large Gardening Web Sites

The Virtual Garden
http://www.vg.com/
One of the oldest gardening sites and still very handy. In the "locate your zone" link, find your hardiness zone by keying in your ZIP code. We especially like the "find a source" link to Barbara Barton's Gardening by Mail database, described below under "Buying Plants, Seeds, and Supplies."

The National Gardening Association
http://nationalgardening.com
http://www.garden.org
This nonprofit organization uses gardeners from all over the country to contribute Web content. We use its regional reports, Frequently Asked Questions, and its Gardening with Kids sections the most. Other sections include Gardening Resources (articles, dictionaries, Q. & A.) and Community (events calendar, message boards, and seed swaps).

The Gardening Launch Pad
http://gardeninglaunchpad.com/
Created by Jim Parra, garden center coordinator at Zilker Botanic Gardens in Austin, Texas, this is one of the largest collections of gardening Web links — over 4,300. It updates regularly and its topical organization reflects the way gardeners seek information.
 

Reliable Sources: Where to Find Expert Advice on the Web
Since growing conditions are local, the best advice may be found in your own backyard. Two local approaches: one — consult experts from nearby botanical gardens and arboreta; two — consult Web sites of local cooperative extension services.

Many public gardens and arboreta have plant clinics. To find a nearby public garden, search the members' list of the American Association of Botanical Gardens and Arboreta (AABGA) site [http://www.aabga.org].

Cooperative extension services dispense trustworthy gardening advice. Many use trained volunteers, called Master Gardeners, to answer questions at plant clinics, via telephone, or e-mail. Master Gardeners' Web pages often publish factsheets of common local pests and diseases.

To find your state's Master Gardener programs, search Google using these terms: [State Name] Master Gardener.

Or, go to MasterGardeners.com at http://mastergardeners.com.
 

Universities and Government Agencies

Ohio State University WebGarden; Horticulture and Crop Science in Virtual Perspective
http://webgarden.osu.edu/
If I could limit my recommendations to a single Web resource, it would be this site's Plantfacts database. Plantfacts has over 20,000 plant factsheets from 46 universities and government institutions in the U.S. and Canada. Factsheets usually include recommended cultivars, cultivation instructions, and lists of common pests and diseases.

Ask Our Experts at the Plant and Pest Diagnostic Laboratory, Purdue University
http://www.ppdl.purdue.edu/ppdl/ask_expert.html
Experts at Purdue's Plant and Pest Diagnostic Laboratory post answers to questions on animal pests, insects and mites, and plant diseases. Surely the most intriguing pest problem is "Lemmings in Our Graveyard," but "Moles in Lawn" and "Cats in Houseplants" are also worth a look.

Oregon State University. Extension Toxicology Network. ExToxNet FAQs
http://ace.orst.edu/info/extoxnet/faqs/index.htm
This site has a FAQ section on gardening, pesticides, and health concerns.

Poisonous Plants
People often wonder if a plant is poisonous to their children or pets. Cornell University has a Poisonous Plants Home Page at http://www.ansci.cornell.edu/plants/plants.html. Agriculture Canada's poisonous plants page downloads more quickly than Cornell's: http://res.agr.ca/brd/poisonpl/.

TreeLink
http://www.treelink.org
Created by the National Urban and Community Forestry Advisory Council of the USDA Forest Service, this site carries educational materials, how-to guides, discussion forums, a quarterly Web-zine, a link list of national and local resources, late-breaking news, and interactive tools for tree identification and selection. This site is for the urban forestry community, researchers, arborists, volunteers, and K-12 environmental education teachers.

U.S. Fish and Wildlife Service and USDA
The U.S. Fish and Wildlife Service site lists endangered and threatened plants [http://endangered.fws.gov/wildlife.html].

A gardener's quest for unusual plants doesn't stop at national borders. U.S. importation regulations and permits can be found on the USDA's animal and plant health inspection service, plant protection, and quarantine page [http://www.aphis.usda.gov/ppq/].
 

The Green Industry: Trade and Professional Associations
"The Green Industry" includes growers, importers, sellers, manufacturers, and service providers. Many Green Industry sites are for practitioners. The Netherlands Flower Bulb Information Center [http://www.bulb.com] site, however, serves consumers, with sections on bulb basics, frequently asked questions, indoor bulb forcing, bulb history, lore, and facts.

International Society of Arboriculture Certified Arborists List
http://www.ag.uiuc.edu/~isa/arborists/arborist.html
Trees can be a homeowner's most expensive landscape feature. Arborists have expertise, tools, and machinery for proper tree care. This trade group maintains a database of certified arborists. A search by ZIP code yields nearby arborists. See also ISA's page on tree care [http://www2.champaign.isa-arbor.com/consumer/consumer.html].
 

Plant Societies and Specialties
Lists of plant society Web sites are easy to find on the Gardening Launch Pad site. Two outstanding examples of society sites are The American Orchid Society's Orchid Web [http://orchidweb.org], with a Beginner's Corner and orchid culture sheets, and the North American Rock Garden Society [http://www.nargs.org]. Rock gardeners covet rare or unusual plants and are usually highly skilled gardeners.
 

Community Gardening

American Community Gardening Association
http://www.communitygarden.org/
Do you want to learn how to start and maintain a community garden? This site covers group gardening's joys and challenges.
 

Databases for Cultivated Plants
This is a weak area on the Web. While such databases do exist, to date, none are as comprehensive as books in a basic gardening library. Authority, too, is a problem. When I consult The New RHS Dictionary of Gardening, I know an army of botanists and horticulturists oversaw its creation and the world's most respected horticultural society — the Royal Horticultural Society — produced it. Who created the records for NeoFlora [http://www.neoflora.com], which claims to be "the world's largest plant database"? NeoFlora is vague about this. How does NeoFlora add new entries? By asking gardeners to submit records to it. While cooperative database-building does work (witness OCLC's WorldCat), is this the best way to grow a plant database? Who will solve thorny taxonomic questions? Where is quality control? (Think catalogers are fussy? Talk to a taxonomist!) That said, The New RHS Dictionary sells for $312. NeoFlora is free.

Sierra Home Network Plant Encyclopedia
http://gardening.sierrahome.com/encyc/
Again, I could not figure out who created this database, nor could I determine how many plants it covered. This encyclopedia also appears on the Yahoo! Living site [http://living.yahoo.com/living/garden/plant_search/].
 

Databases for Plants Found in the Wild

USDA's Natural Resources Conservation Service's National PLANTS Database
http://plants.usda.gov/plants/
On the other hand, this is an authoritative database. Many gardeners use native plants. This database includes "vascular plants, lichens, mosses, liverworts, and hornworts that occur spontaneously within the United States" (quote from the Web site). The site divides into topics, images, links to related sites, and tools. PLANTS can generate reports of invasive and noxious plants, for example, the bane of all gardeners.
 

What Plant Is That? Plant Images in Print and on the Web

Plant Information Online
http://plantinfo.umn.edu
The University of Minnesota Libraries produces this resource, edited by Richard T. Isaacson of the Andersen Horticultural Library and Katherine Allen, Plant Sciences Bibliographer, Magrath Library of the University of Minnesota. Users pay a fee for most of this site, but it's a bargain, at $59.95 per year.

Plant Information Online's Citations to Plant Information and Illustrations database includes over 150,000 records of plant color illustrations and information on 75,000 flowering plants.

For plant images on the Web, start with Katherine Allen's Plant Images on Web Sites and CD-ROMs: An Evaluative Review in a "free" section of Plant Information Online [http://plantinfo.umn.edu/arboretum/table/intro.html].
 

Buying Plants, Seeds, and Supplies

Plant Information Online. Sources for Plants and Seed
http://plantinfo.umn.edu
For years, horticultural librarians have used the printed version of this database — Andersen Horticultural Library's Source List of Plants and Seeds. Find mail-order sources for over 70,000 plants cultivated in North America.
 

The Garden Tourist

The National Gardens Scheme
http://www.ngs.org.uk/
The U.K. is to gardening what France is to cooking. Every year, the National Gardens Scheme opens thousands of "must see" private gardens to raise funds for charities. For years, garden mavens relied on the annual guide, The National Gardens Scheme Gardens of England and Wales Open for Charity to plan when, where, and which outstanding private gardens to visit.

Conveniently, this guide is for sale on the NGS site. Better still, search the site's GardenFinder database (which also includes Scotland) by garden name, keyword, county, and a date range.

The Garden Conservancy
http://www.gardenconservancy.org
The Garden Conservancy is the U.S.' only national nonprofit organization dedicated to garden preservation. Its site describes current projects and member gardens, such as The James Rose Center for Landscape Architectural Research and Design in Ridgewood, New Jersey and The Beatrix Farrand Garden at Bellefield in Hyde Park, New York.

The Garden Conservancy produces an annual Open Days Directory (in print form) as a guide to private U.S. gardens open to the public. The order form appears on the site.

Garden Web Calendar of Garden events
http://www.gardencalendar.com/
Search for all events, or restrict your searches to flower shows, festivals, plant sales and swaps, garden tours, lectures, workshops, and seminars. Remember, gardening groups often publish their events on their Web sites.
 

Libraries and Book Sources, Videos, and Software

Horticultural and Botanical Libraries

Council on Botanical and Horticultural Libraries (CBHL)
http://huntbot.andrew.cmu.edu/CBHL/CBHL.html
CBHL is an international organization of botanical and horticultural librarians, botanists, book dealers, and collectors. This site describes CBHL's activities and lists Web addresses of member libraries. Some, like Harvard's Botany libraries and the New York Botanical Garden library, are large research collections. Other libraries are smaller, but all share an interest in horticulture and botany. With in-depth collections reflecting local growing conditions, CBHL libraries serve as regional horticultural information centers. For example, Seattle's University of Washington Center for Urban Horticulture's Miller Library has an excellent page of annotated links, "Pacific Northwest Gardening Gateways" [http://depts.washington.edu/hortlib/links/pnw.gateways.html].

CBHL members are specialists in their field and generous in sharing their time and expertise.

Gardening Book Reviews
To find gardening and landscape architecture books reviewed in The New York Times, search its Book Archive, a database with over 50,000 reviews and author interviews back to 1980 [http://search.nytimes.com/books/search]. Of course, most of the reviews cover non-gardening material, so you should know key bibliographic information on the books you want to check — title, author, etc.

Every February or March, Publishers Weekly [http://www.publishersweekly.com/] publishes an article on gardening book publishing trends. I found the 2000 gardening trends article under the "features" link of PW's Web site.

Out-of-Print Books
CBHL lists horticulture and botany book dealers at [http://huntbot.andrew.cmu.edu/CBHL/CBHL-Booksellers.html]. See also BookFinder [http://www.bookfinder.com/], a gateway to aggregated listings of over 15,000 new and used booksellers worldwide.

Videos and Software
A.C. Burke & Co. [http://www.acburke.com/index.html] specializes in gardening videos and software. Its catalog uses useful subheadings, such as "flower arranging," "fruits and vegetables," and "garden history and tours."
 

The Garden Historian: Garden and Landscape Design History Sites
The summary below lists U.S., Canadian, and a few U.K. resources.

Good Starting Places

University of California, Berkeley Environmental Design Library, History of Landscape Architecture
http://www.lib.berkeley.edu/ENVI/histland.html
A detailed and sensibly arranged guide to the literature of this field.

Garden History Links
http://www.magi.com/~evb/garden.html
Well-organized list arranged geographically and by subject, by Edwinnia von Baeyer, author of Rhetoric and Roses: A History of Canadian Gardening, 1900-1930. My only quibble is that some links need updating.

Encyclopaedia Britannica
http://www.britannica.com
Use search terms "garden history" and "landscape design history" to get recommended Web sites, links to EB's gardening history articles, and related magazine articles.

CATALOG of Landscape Records in the United States at Wave Hill
http://www.wavehill.org/landscape_research/index.html
This invaluable project, headquartered at the Wave Hill garden in the Bronx, "gathers information about the location and content of collections of documents (both written and graphic) that tell us about the use of our land. These could include maps, planting plans, nursery catalogs, personal or business archives, photographs, postcards, aerial photographs, real estate brochures, deeds, etc. This information is arranged and entered into the CATALOG's database" (quote from Web site). The database is not on the site, but CATALOG staff will search it in response to inquiries. There's also an informative newsletter on the site and in print.

Visual Resources

Archives of American Gardens
http://www.si.edu/resource/tours/gardens/aag.htm
The Smithsonian's Horticulture Library houses 60,000 photographic images and records documenting historic and contemporary American gardens. Its database is deeply buried in the Smithsonian's vast Web site. To find it, go to the SIRIS (Smithsonian Institution Research Information System) Archives and Manuscript Catalog search page [http://www.siris.si.edu/webpac-bin/wgbroker?new+-access+top.siarc].

Click on the pull-down menu for the field "Repository" and choose "Archives of American Gardens." Then perform your search.

American Memory Project at the Library of Congress. Image Databases. American Landscape and Architectural Design, 1850-1920
http://lcweb2.loc.gov/ammem/award97/mhsdhtml/aladhome.html
Here you will find digitized images from 2,800 lantern slides owned by Harvard's Loeb Library of the Graduate School of Design. This study collection "offers views of cities, specific buildings, parks, estates and gardens, including ... hundreds of private estates from all over the United States" (quote from Web site).

Biographical Information
The most complete American reference to biographical information on landscape architects is the recently published book, Pioneers of American Landscape Design, Charles A. Birnbaum, Robin Karson, eds., New York, McGraw-Hill, 2000.

For me, a Web surprise was A&E Television Network's Biography Web site [http://www.biography.com]. Within 5 minutes of searching, I found brief but useful entries for a dozen historically significant plant people. This site's database combines entries from the Cambridge Encyclopedia and the Cambridge Dictionary of American Biography. My only quibble is that search is limited to name only — no access by subject or date.

Garden History Journals

Garden Literature Review: Garden History and Period Gardens
http://www.gardennet.com/GardenLiterature/glitrv11.htm
Sally Williams, editor and publisher of Garden Literature, writes a thorough review of garden history journals, periodicals, and newsletters, with emphasis on American and British publications.

Garden & Forest: A Journal of Horticulture, Landscape Art, and Forestry
http://lcweb.loc.gov/preserv/prd/gardfor/gfhome.html
Garden & Forest (1888-1897) was "the first American journal devoted to horticulture, botany, landscape design and preservation, national and urban park development, scientific forestry, and the conservation of forest resources" (quote from site). This is a digital reproduction of all 10 volumes, comprising 8,400 pages and over 1,000 illustrations.

Heirloom Plants
What are "Heirloom Plants"? The Complete Gardener's Dictionary (Barron's, 2000) defines heirlooms as "cultivated forms of plants that originated before 1940; hybrids only became common after World War II." Heirloom plants, also called "historic" or "antique" plants, are often used in reconstructions of historic gardens and landscapes. A Google search with these terms will yield links about heirlooms and sources for them.

Thomas Jefferson Center for Historic Plants
http://www.monticello.org/chp/
This program "collects, preserves, and distributes historic plant varieties and strives to promote a greater appreciation for the origins of garden plants in America" (quote from Web site). While the emphasis is on plants grown by Jefferson, the center documents plants grown throughout the 19th century.
 

Keeping Up — The Wired Gardener
The McLean Library staff produces The Wired Gardener, a free, monthly e-mail newsletter of gardening Web sites and book reviews, search tips, and news of gardening happenings. We have thousands of subscribers from the world over. To subscribe:

Send an e-mail message to LISTSERV@HSLC.ORG.

Leave the "subject" line blank.

In the body of the message, type SUBSCRIBE WIREDGARDENER firstname (space) lastname.
 

Conclusion: Toward a Greener Web
I hope this article will guide librarians to accurate gardening information on the Web.

What's in short supply on the Internet? Good gardening writing. Like travel writing, garden writing can be a pleasure to read, with well-crafted, often inspired, writing. On the Web, you won't find much of Henry Mitchell, Vita Sackville-West, Andrew Jackson Downing, Allen Lacy, Katharine White, or Elizabeth Lawrence. But you can find the catalogs of garden libraries (like the CBHL libraries) and seek these authors there — or perhaps dig them up in your own library.
 
 

Janet Evans is library manager of the Pennsylvania Horticultural Society, and a past president of the Council on Botanical and Horticultural Libraries. Her e-mail address is jevans@pennhort.org.