Plant identification of woody weeds

Weed image by Necroborg from

The woody weed has been a thorn in the side of gardeners and landscapers for years. Advancements in herbicide technology and knowledge of how weeds grow allow today's gardeners to eradicate woody weeds successfully wherever they grow. However, the first step in treating any sort of weed is identification.


Identifying woody weeds, like many other plant species, is essentially a process of elimination. The person who does the identification will often start with obvious, unique, structures of the plant, such as a flower or thorns, and work from there to create a list of characteristics. Trained experts or people who do this for a living usually create mental lists and work backwards by eliminating possible plants until they reach a conclusion about what the weed actually is. However, novice gardeners or those who have not done much identification should begin by systematically noting on a piece of paper each characteristic about the weed. From there the list of characteristics can be compared to horticultural encyclopedias or online databases to come up with a positive identification.

What to look for

One of the toughest challenges for novice identifiers is knowing what to look for and take note of. The first, and most obvious rule, is to make note of anything that catches your eye or seems strange (unique flower, interesting structure, thorns, etc.). However, one of the best sources of plant characteristic is the leaf. Leaf analysis is a key component to identification and simply looking at the leaf can give you a multitude of information. Measuring the leaf, analysing the leaf's structure and even determining how the leaves come out of the main branch (when compared to each other) are vital pieces of information. Overall height and width of the weed may be important to note, but because weeds very rarely reach mature dimensions and stop growing, these measurements can be misleading when used by themselves.


Woody weed identification, particularly when it comes to leaf analysis, will often require the identifier to be familiar with some horticultural terminology. For example, leaves that branch off the stem exactly across from each other on the same point are said to be "opposite" or "opposed" as compared to "alternate." Leaf shape is another area where horticulture terminology runs rampant. Beginners should familiarise themselves with this lingo before proceeding to any horticultural encyclopedias. Luckily, online identification tools will describe these terms and show pictures to help the identifier.


One of the best places to start a woody weed identification is with your location. Every state has a list of noxious weeds, which have been composed into both state and federal databases. By starting with a list of woody weeds that are the most problematic for a particular state or region, the person attempting the identification can save a lot of time and effort. These lists are readily available online and in print.

Where to go for help

Sometimes, even after a very thorough identification, it may be difficult to conclusively determine what a particular weed is. Luckily, experts at garden centres and university cooperative extensions are there to help everyday gardeners who are stumped in their efforts. Gardeners and landscapers should bring a sample that includes, if possible, an area with leaves and flower or any other distinguishing feature. Pictures are always helpful and a description of the area where the woody weed is growing can also be helpful.