What does that word mean? Weed terminology 

Plants that go through their entire life cycle from seed to flower to seed within one year or less.  All roots, stems and leaves of the plant die annually, and the next year’s plants are grown from seeds that have overwintered in the ground.  Some annual weeds, like Cheatgrass, can complete their life cycle in as little as a month.  Annual weeds produce copies amounts of seeds and can colonize large areas quickly, but small patches are easily controlled by hoeing or hand pulling due to shallow root systems.

The slender bristles on the end of grass “flowers.”  When weedy grasses dry out the flowers have become seeds and the small, sharp awn is what the plant uses to hitch a ride (think cheatgrass seeds in your socks).  Many awns are barbed and meant to act like one-way drills, presumably into soil, but they can be dangerous infection-causing problems for dogs and livestock.

Basal Rosette
A radiating cluster of leaves, at ground-level, on a plant’s central stem where it transitions to a root.

Complete their life cycle in two years.  The first year, they establish a deep root system and a small basal rosette; the second year, they grow up, flower, produce seeds, then die.  The best control for biennial weeds is hand pulling during the second year because the stem gives you leverage on the deep taproot. 

Biocontrol (Biological Agent)
The intentional use of living organisms (insects) to try to suppress the population of a pest (noxious weeds).  The insects are natural enemies  from a specific weed’s native ecosystem (usually Europe or Asia).  The insects are tested extensively before being certified as biological agents.  Biological agents are alternatives to herbicide but they are a long-term method for weed management as they may not overwinter, and will not eradicate the targeted weed’s population because they depend on the weed for their life cycle.  See the Regional Bioagent Project for more information.

A plant whose above-ground parts die completely each year.  No “woody” stem or fragments from the previous year can be found the next year.  Herbaceous plants may be annuals, biennials or perennials.

Plants that persist for many growing seasons. Perennial weeds grow from extensive roots systems as well as from seed.  The above-ground portion of the plant dies back each winter and new growth comes up each spring from the same root system.  Because roots regenerate after disturbances, perennials are more difficult to eradicate than annuals or biennials.

A plant with rhizomes, which are underground horizontal roots that have spurs or side-roots spreading out and down as well as new shoots going up.  Rhizomatous roots are creeping or spreading root systems, commonly found in perennial plants, that are able to generate new plants from pieces of roots, such as when they are cut with a shovel or tiller.  Weeds with rhizomatous roots, such as quackgrass, whitetop or baby’s breath are difficult to eradicate. 

Compounds that lower the surface tension of a liquid.  In the case of weed control, the word surfactant refers to a soluble compound that is added to herbicide to help the herbicide “stick” to weeds, otherwise the spray could just run off.  Some herbicides already contain a surfactant and some specifically tell you to mix one in before you spray.  There are many types of surfactants, and they are often called stickers.

A relatively large root that goes straight down.  Small, minor roots may come off the taproot, but the taproot is the primary root of the plant.  A plant with a taproot would have an opposite root system from one with rhizomatous roots.  Weeds with taproots can be easy to hand pull if they produce a firm above-ground stem, such as knapweed, salsify or mullein, as the stem gives you leverage on the root.  However, not all weeds with taproots produce hardy stems (think dandelions). 


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