Weeds will drive you crazy if you let them.

Don’t let them.

Instead, be the smart gardener and know thy weeds before you do battle.

There are right ways and wrong ways and right times and wrong times to wage war against weeds. Knowing a weed’s strengths and weaknesses and its correct identity helps you become the victor and not the victim.

Here are nine science-based resources you can use to identify weeds so you use the correct product or method at the correct time. The helpful information comes courtesy of Lebanon Seaboard Corp., which makes Preen weed-prevention products and other gardening and lawn supplies (www.preen.com.).

•  www.ppws.vt.edu/weedindex.htm

Virginia Tech Weed Identification Guide. The most comprehensive online guide to US weeds with more than 600 t species. Search by common name or scientific name, both listed alphabetically. All entries have several good photos and most have excellent descriptive and cultural information.

•  http://www.ipm.ucdavis.edu/PMG/weeds—intro.html

Weed Photo Gallery from University of California. Comprehensive guide to 160 weeds commonly found in California, many of which grow elsewhere too. Here, users search for weeds by type (broadleaf, grass, sedge, aquatic), plant form, mature leaf characteristics or by name (common or scientific). Entries include detailed cultural information and most have photos of the seeds, seedling, flower, mature plant and seed capsule.

•  http://www.preen.com/weeds

Weed ID from Preen. Preen has retooled its online Weed ID tool. Geared to home gardeners, the new Weed ID offers multiple images of each weed, plus four search options: common name, Latin name, grassy or broadleaf type, plus a state-by-state search feature which helps gardeners hone in on the specific weeds that are most likely to crop up in their own garden. Besides images, each weed’s ID offers key information plus solution-based products and videos. Easy-to-use and covering 115 weed species the site also includes links to top university weed resources, making it a good place for home gardeners to start.

•  http://njaes.rutgers.edu/weeds

New Jersey Weed Gallery from Rutgers University. A valuable resource identifying weeds commonly found in New Jersey, many of which grow in other regions. In this Weed Gallery, weeds can be searched in three ways: by common name, by Latin name, or by scanning through the thumbnail images. A thorough descriptive paragraph explains each weed’s unique characteristics and preferred habitat.

•  http://www.extension.umn.edu/gardeninfo/weedid/index.html

Is This Plant a Weed? From University of Minnesota Extension. Gardener-oriented and user-friendly, this photo-identification tool features 75 weed species commonly found in Minnesota, many of which grow in other regions. Searchable by weed type, growing habit and supporting photos, each entry has several photos, a complete list of plant characteristics, notes on significance and a helpful list of similar-looking weeds. Entries are linked to recommendations for cultural and chemical control options.

•  http://weeds.cropsci.illinois.edu/weedid.htm

Weed Science Identification from University of Illinois Extension. This guide lists 68 weed species by common name. While most entries have excellent photos, not all have supporting information. That’s OK: the big bonus here are weed photos so 3D, you want to reach out and pull them!

•  http://weedid.missouri.edu

Weed ID Guide from University of Missouri. More than 400 weed species listed alphabetically by common or Latin name. Each entry features four to eight photographs showing various stages of development. Descriptions are complete and indicate where the weed is typically found plus identifying characteristics. An expanded search option is available for weed-geeks who know whether a leaf is pinnately lobed or palmately lobed.

•  http://www.weedalert.com

Weed Alert from PBI/Gordon Corp. Oriented toward turf professionals, this guide to U.S. weeds has some information that also applies to weeds in gardens. Select a region (Western, North Central, Northeast or Southern) to get a list of weeds by common name with an accompanying photo, cultural information, germination dates and control recommendations. Information on more than 170 weed species.

•  For weed pros and fanatics:

Dr. Richard Old, president of XID Services and weed identification specialist for Washington State University and Extension, offers the ultimate comprehensive weed ID tool presented as an interactive DVD: 1200 Weeds of the 48 States and Adjacent Canad a (http://xidservices.com/order). Cost is $49.95 plus $5 for shipping.