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pasture weeds with seed heads

Chickweed is a common weed. With many varieties, ‘Common Chickweed’ is the most encountered. A small plant with shiny leaves with multiple stems, Chickweed produces a single white flower on each stem. Its invasiveness into healthy lawns is rare and it doesn’t like to compete. Chickweed prefers to germinate and grow barer patches of turf. Chickweed cannot recover from the loss of its foliage, so regular mowing of lawns ensure its eradication – which is another reason chickweed is rarely…

Purslanes and Portulaca are a low growing 0 to 200mm high, a prostrate to decumbent often flowing succulent annual weed. Stems and runners are normally soft and pink to brown in colour. They are very common in a variety of soil types especially after having been recently disturbed. There are many varieties of this weed across Australia some native and introduced widely naturalised and a prolific seeder. Grows well in temperate to tropical regions. Seed mostly germinates around autumn, colonies…

Crabgrass is nuisance value to lawns everywhere. It is both a prolific seeder and spreader, overtaking lawns as it continues to spread. Removal of this grass weed as soon as possible is important. The crabgrass suffocates your lawn then dies off in winter, leaving bare patches in your dormant lawns. Following spring the bare patch becomes a stronger weed from the previous seasons seeding and the problem continues to deteriorate. Crabgrass is listed as one of the 12 worst weeds…

Catsear (Hypochoeris Radicata)

Onion Grass is a perennial grassy weed with between three and 10 thin, strappy leaves rising from the central base up to 30 cm long. The leaves are up to 2 mm wide with a prominent central midrib that protrudes to create an almost cylindrical leaf blade in cross section in a spear and quite a tough point. Flowering in spring, the onion grass plant produces two to four small flowers per plant that are positioned around the base of…

Mullumbimby couch is a perennial grass-like sedge up to 15 cm high with dark green, glossy, strap-like leaves. It has tough, long rhizomes that are red to purple in colour and triangular stems in cross-section which is characteristic of sedges. This sedge is in mostly observed in flower through spring and summer and presents as a single round, compact spike with three short, curved leaves protruding from the base of the seed head. Mullumbimby couch grows best in areas of…

Weeds are identified into a few categories:

Mallow or marshmallow is native to Europe, Asia and northern Africa but has made itself at home in all Australian states. It grows in every soil type and is commonly seen in disturbed areas such as roadsides, cultivation, around buildings, stock yards, along watercourses and in rundown pastures. At Lawn Addicts, we provide recommended herbicides and lawn care programs to control mallow and other broadleaf weeds.

Now that we have addressed the needs of the grasses, how about our other problem with pastures: weeds. My colleagues Mark Landefeld, Ted Wiseman and Jeff McCutcheon are in the fourth year of trying to determine when is the best time to mow pastures to control weeds. We have research plots at the Eastern Agricultural Research Station near Caldwell, Ohio, that are mowed at different times. Some plots get mowed one time a year in June, July, August or September; some plots all four times (each month); the control plots (not at all); and we have plots that are mowed in June and August; or July and September. The results of the 2017 study suggests that mowing in June and August works as good as mowing every month to control weeds, and the June mowing will remove the seed heads. With the late start of the season we have had this year, this strategy may be an option depending on your weed pressure.

Finally, it is critical to give the plants a chance to rest after being mowed or grazed. This will allow the plants to store energy in the roots or base as the leaves grow.

The spring of 2018 was the latest I can remember feeding hay to cattle, and many producers were searching at the last minute to find some extra hay. Pastures were very slow growing this spring until it finally warmed up in early May. On my farm, common orchardgrass typically starts heading out in late April, and it was two weeks later this year. The late-arriving spring brought many challenges around farms, and the rush to get crops in the ground and to make hay has put mowing pastures on the backburner. However, now may be a great time to mow pastures.

For many of us, we are lucky if we’re able to mow pastures once a year, but consider what the needs and priorities are for your pastures. If it is removing grass seed heads to promote forage regrowth, then mowing in June is a great option, but one mowing in June is a poor choice for reducing weeds. If perennial weeds are a problem, consider mowing them just before their seed heads become viable. Plot data appears to show that it is best if you can mow twice — once to remove seed heads, and then again to suppress persistent weed problems like the June and August option.

Our perennial grasses go through two stages during the growing season: the reproductive stage and the vegetative stage. When grass starts growing in the spring, its main objective is to reproduce, resulting in a seed head. The net movement of energy is up. Once it has produced a seed head, it will transition from the reproductive stage to the vegetative stage, and hopefully the net movement of energy will be down. At that point, the plant wants to store enough energy in the roots or base of the plant to survive through the winter. It is at that point of transition when it is a great time to mow pastures. Once the plant has set a seed head, the quality of the grass, especially the stem and seed head, is low. Removing the stem and seed head will even stimulate new growth. At this point, new growth will be leaves, which will be high in quality for livestock, and the leaves will capture sunlight and provide energy for the plant. While grass has been headed out for a while, mowing pastures soon to remove seed heads is a great option if needed in our pastures.

We need to keep in mind the three big grazing principles to make pasture management successful: avoiding seed heads, residual management, and rest periods. I have started to cover the first principle, but as I transition to residual management, cutting height can play a big role with how close animals will graze and what type of forage will be favored. I have consistently noticed over the years that after I mow a pasture, especially with a sickle bar mower, my cattle will readily graze the new growth. But grazing intensity will slow if they need to graze into the previously mowed stubble, especially in pastures with thick stemmed grass like fescue and orchardgrass. We have some ability to influence how close cattle graze. In addition, cutting height can influence what type of grass will grow. For example, orchardgrass stores its energy in the base of the plant above ground. If we mow or graze too close, we may eventually kill off that plant and possibly favor growth of fescue, bluegrass and weeds. If we graze or mow higher, we favor orchardgrass growth and allow all the grasses to continue leaf development without the roots ceasing growth to produce new leaves.

With all of the other activities we have to accomplish on our farms, sometimes mowing pastures falls down on the list of things to do. If you can evaluate the needs such as seed head removal and weed control, maybe we can better time our pasture mowings.