When preparing high quality turf for playing golf and other sports, weeds can be a major nuisance. Apart from being unsightly (Fig 1 on left), they can affect the way that balls travel across the turf, they often don't handle wear as well as good quality turf, can affect traction when players move across them and can also result in prickles and bee-stings.
To get good control of weeds, it is important to correctly identify them so that the most appropriate management and
herbicide strategies are used to remove them. This article will discuss the identification, biology and control of the main weed shown in Fig 1, ribwort, and also some other plantains. Other weeds will be discussed in future issues of Golf and Sports Turf Australia.
Many of the troublesome weed species in turf grow as rosettes, with a central growing point at ground level and leaves radiating out from this point. Although the ends of leaves may get removed by mowing, the growing point continues to push out more leaves, and also seed-heads at certain times of the year. The plantains are one group of weeds that grow
this way. They belong to the Plantaginaceae family, and there are over 20 species in Australia. Two of the more common plantains are ribwort (Plantago lanceolata) and greater plantain (Plantago major). Ribwort is also known as common plantain, plantain, narrow-leaf plantain, lamb's tongue, ribgrass and ribwort plantain. Alternative names to greater plantain used around Australia include large plantain, great plantain and broad-leaved plantain.
IDENTIFICATION
When weeds are vegetative, one way of telling apart these two plantains from other turf weeds which grow as rosettes is that the margins of the leaves have no lobes (Fig 2), unlike other common rosette weeds such as dandelion. However, not all plantains have this characteristic, as another common plantain in Australia is buck's-horn plantain (Plantago coronopus), which does have narrow, finger-like lobes down each side of the leaf (not illustrated in this article). Plantain leaves also have distinct ribs travelling down their length, which is probably how ribwort got its name. When a leaf is broken, these veins are noticeably very "stringy". Other rosette weeds in turf either don't have distinct ribs, or they have one distinct rib down the centre and other ribs radiate from this central rib outwards to the leaf margins.
Once plantains are flowering, they are even easier to distinguish from most other rosette turf weeds. Many of these other species belong to the Asteraceae family, such as dandelion, Capeweed, daisy and catsear. Most of these have colourful flowers and produce seeds with "feathery" pappus that blow around in the wind. However, the seed-heads of the plantains are brownish or greenish and much more "spike-like" (Fig 2).
Although the two plantains being described are both perennial weeds (i.e. capable of living for several years), they usually do not form the distinct tap-root systems found in many other rosette weeds. Both species generally have a definite crown just below ground level. However there are usually a large number of adventitious roots spreading downward from this crown rather than a distinct tap-root. With ribwort, a short thick rhizome also often forms from which new plants can develop.
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As suggested by some the alternative names for these two plantains, ribwort leaves tend to be narrower than those of
greater plantain (Fig 3). Greater plantain leaves also become much narrower near the base to form a distinct "stalk". The width changes much less from one end of the leaf to the other in ribwort.
The other main difference between the two species involves the seed-heads. With ribwort, the seed-head tends to be clustered right at the end of the stalk, whereas the seeds are spread much further down the stalk in greater plantain
(Fig 3). Buck's horn plantain has seed-heads that are intermediate in the spread of fruits along the stem.
HABITAT
Both of these species are found in a wide range of habitats throughout most temperate and tropical countries in the world, suggesting they are very adaptable. Plantains are generally found more in higher rainfall areas of Australia. Greater plantain is better able to tolerate compaction, water-logging and treading than ribwort. Ribwort can tolerate drier conditions better than greater plantain.
Although plantains are claimed to prefer neutral or basic soils to acid soils, they still seem to cause lots of problems when the soil pH is 5.0. Plantains tolerate low fertility soils very well.
As with most weeds, new plantain plants will usually only establish successfully from seed if there are gaps in the turf. However plantain seeds can last at least 60 years in the soil, so there are probably lots of plantain seeds ready to germinate if the turf opens up. Despite being perennial species, they will often act as annuals or biennials in situation of lower rainfall, dying off when conditions become too dry and re-establishing from seed once moisture levels become more favourable for growth.
Buck's horn plantain differs from these other two plantains in that it has a very high salt tolerance, and is often found in coastal areas and sites with salinity problems.
CONTROL
Compared with many turf weed species, plantains are fairly easy to remove selectively from grass turf using herbicides.
They are susceptible to most of the "hormone-type" herbicides. MCPA is usually adequate by itself, but control can also be obtained using 2,4-D, mecoprop, dichlorprop or picloram (Note that I am using mainly the names of active ingredients here, as there are many different trade-named products available for turf, some with several names for the same mixture). Dicamba used by itself is not very effective. Clopyralid should be used at the higher recommended rates. With all of these herbicides, the plantains need to be growing actively in a moist soil for best results. Ioxynil and bromoxynil by themselves tend to be only effective at removing plantains while they are young seedlings. |
