Yes, wo do still have a wet season in Southern California. Alright, Washington State, we get it, you have a lot more rain, but the heavy clouds still bless us here down south with the occasional washing. Let’s take a look at some of the more common winter weeds and what we can do about controlling them as best we can.
Winter annuals (plants that go through their entire life cycle in one season) normally germinate in the fall or early winter and flower and produce seed by early summer.
Common types: annual bluegrass, annual ryegrass, annual sowthistle, common chickweed, common groundsel, clover, and plantain.
Most annuals can be controlled in the landscape with an integrated program of mulching, hoeing, hand-weeding, or spot application of an herbicide.
If herbicide is used is used, winter annuals may be controlled by a preemergent herbicide applied during fall and a contact or translocated herbicide applied during winter.
1) Annual Bluegrass
Poa annua is a winter annual adapted to cool, moist sites, however it can grow an time of year in coastal areas, especially in shady, moist areas. It grows 3 to 12 inches at maturity. Its flower heads are branched with clusters of 3 to 6 flowers at the tip of each branch.
In ornamental plantings bluegrass can form dense patches that are aesthetically distracting, but probably have little detrimental effect on established shrubs and trees.
Annual bluegrass reproduces by seed and can have many generations in a season.
Control: mulching, hoeing, hand-weeding, or spot application of an herbicide.
Annual bluegrass seedling
Mature annual bluegrass
2) Annual Ryegrass
Annual ryegrass (Festuca perennis) is a cool season well adapted to sunny conditions and moderate temperatures.
It is often sown at high rates to overseed warm season turfgrass for fall, winter, and early spring color. It is not otherwise used for turf. Annual ryegrass dies in the late spring to early summer. It often turns yellow and dies before warm season grasses come out of dormancy.
Mature annual ryegrass
Plant structure of annual ryegrass
Plantain (Plantago major & Plantago lanceolata) is a common weed in year round. Both types have a fairly weak root system, however they grown from the base and mowing will not kill them.
Plantain commonly grows in turfgrass and their seeds and vegetative structures will contaminate equipment.
Remove plantains as early as you can, before they seed. Once you see a plantain in a spot, make sure to keep and eye on that area even after removal. Resprouting is common. Plantain control requires diligence over a period of time.
To be continued (because weeds will always come back)…