Notes on brome grass (greater brome, ripgut brome, Bromus diandrus)

This is a post to record some notes from my current reading, on the assumption that I’ll forget what I’ve read if I don’t write it down.

• Ripgut brome – common name for two species, diandrus and rigidus. Better common name is greater brome. I have high density of diandrus in zone 4, don’t think I have rigidus anywhere.
• Many bromes. Some are perennials, useful for pasture. These ones are very much not good for animals or for forage/fodder.
• Cool-season-emergence grass, a “winter grass” tribe. Needs moisture as well as chilling so emergence is staggered on non-wetting soils like Bassendean sands. Also needs burial.
• Difficult to control as very closely related to wheat/oats etc. Some herbicides are useful but resistances are developing. This may be less of a problem for me as I’m not mixing them with other grasses.
• Because of this there is lots of information / research on its control going on around the country (ag depts, BCG, others) and in other Mediterranean-ag countries. No-till practices increase its impact and need for management.
• Autumn tickle (light soil turnover) combined with soil wetter application and a (chilled?) watering will get me a high germination rate of existing seed bank in order to apply other control options.
• Seed life is three years nominally, but seedbank reduced to less than 10% after two years. Need at least two years of attack.
• Seeds need a short time of hot to set and break dormancy.
• Heavy seedset, but if not turned into ground, perhaps a heat-control method like my windowing to kill seeds? Haven’t found notes on what temperatures kill them other than burning. Burning noted as a partial control method (brome seedfall is irregular in timing so seeds may escape post-grain-harvest control methods).
• Root system definitely over-competitive with citrus, needs complete removal from those areas. May be more feasible amongst other crop trees.
• Weed mat under the citrus? (after germination is induced). Would also block my volunteerscape from regerminating. But might be worth it to knock down the brome grass.
• Green manuring is an option for control. May be tricky under the citrus as I’m trying to avoid the root disturbance, but could apply it across the other main infestation point behind the pistachios.
• Can the problem be an opportunity in my situation?
• Haven’t found any alternate use by humans. Some bromes used for fermented beverages. Query whether this is possible with diandrus – if so, it might be an option.
• Hazardous to small mammals with long hair (eg longhaired cats and dogs) due to their mechanical action to burrow into skin. Will also affect shorthaired mammals but the seeds are usually knocked off before major damage is done to these.
• Possible caterpillar food for some butterflies?
• Doesn’t make good hay as that’s spreading seed 🙂 but, cutting before flowering to use as green manure / silage / fermentation fodder might work.
• Fermenting might be my best bet, come to think of it. Broad scything followed by fermenting down. Need more fermenting capacity to do it though. Highly siliceous leaves so not a soft/fast breakdown.
• No information about nutrient concentration / absorption that I’ve yet found, so no clear indications on their impact on soil other than that they can be heavy feeders. That also indicates fermentation / green manuring as a possible problem-to-opportunity solution at food-forest scales.
• Heavy grazing also recommended for control of several Bromus species. Regular mowing/scything this year, and accept losses of other volunteer species?

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