Quackgrass!!

Quackgrass - Agropyron Repens - A Perennial Weed

Keeping it Out Of Flower and Vegetable Beds

Pictures, research, and information gathered by Susan Berman

Many community gardens in Toronto suffer from an invasive grass called Quackgrass, or - Agropyron Repens. The Latin name means a 'sudden field of fire', and attests to its ability to take over lawns, fields and gardens. The plant is hardy to zone 3 and is actually native to Europe. It has been growing in North America for over 200 years

In older books quackgrass may be referred to as couch, quitch, devils wheat, scutch, twitch, witch, dog or durfa grass. This plant is listed as a noxious weed because of the detrimental effects it has on agricultural crops, though it does help control erosion.

Understanding how it Grows -

An understanding of how the quackgrass grows will help avoid common errors in battling this plant. Quackgrass grows from underground rhizomes to an unmowed height of 1 to 4 feet. It has thin, flat, bright ashy green leaf blades. The seed spike grows from 3 to 8 inches long and appears in July. Quackgrass seed is often found in rye straw, so you may want to avoid using this as mulch in your garden. Each quackgrass plant produces about 25 seeds; they remain viable 3 to 5 years in the soil. It takes 2 to 3 months for a newly germinated plant to develop rhizomes. It is very important to eliminate the plants before they reach this stage. (excerpts from the University of Minnesota - extension service)

• Above: A picture of the quackgrass and the rhizomes.

• Right: A life size picture of a rhizome, note the point at the end, I have seen garlics and onions pierced through with these rhizomes

• All photos are from the Perth Dupont Community Garden

From the desk of Chris Martin - Parks Forestry & Recreation:

Regarding grasses invading worked bed like vegetable plot, this also happens with horticulture beds like annual beds. This is dealt with by maintaining an edge where the grass meets the bed. Thus this maintenance activity is called bed edging. If you check ornamental vegetable gardens at Botanical Gardens like Montreal, University of British Columbia, Kew Gardens in England and Niagara Parks Commission you will see aforementioned edges around ornamental vegetable plots where grass flanks the bed.

I have seen some gardeners place various types and sizes of edging material e.g. timber, plastic, iron, aluminum, stone, bricks etc and invariably the grass stolons work their way under or through the edging material to the cultivated soil area. I have only noticed that high e.g. about 2 ft high raised beds are able to keep turf grasses out.

Edging can be aesthetically pleasing e.g. straight lines in formal annual beds or organic curved lines in mixed borders with annual, perennials and shrubs.

Maintenance is involved in keeping the edge functional and many vegetable gardeners do not wish to spend time on dealing with it, consequently they have to deal with invading grasses into cultivated beds or conversely plants like strawberries, raspberries or pumpkin vines leaving the cultivated area and invading adjacent turf areas.

Edge Development and Maintenance involves:

IN THE SPRING

• (1) dig a straight edge and 6 inch trough around the vegetable plot where ever grass is adjacent the plot. One can use string lines or a garden hose to help make it straight if desirable or if you have a "poor eye" when using a turf edger or spade.

• (2) remove weeds from the excavated soil to form the edge and trough which was been placed on the top of the vegetable bed. Remove weeds from within the bed as well.

• (3) incorporate amendments into the bed i.e. by forking, spading or tilling the soil

• (4) re-establish the 6 inch trough adjacent the turf edge then rake bed area "roughly" level. Note need to make the trough deeper than 4 inches so when you rake the bed level the final trough depth will be at least 4 inches

• (5) if you have a hand pulled water filled roller, fill the roller to about 3/4 full, and roll the bed as well as the angled soil edge around the perimeter of the bed a couple of time.

• (6) do a final re-raking / leveling of the bed

• (7) final quickly re-establish the 4 inch trough to remove any soil that may have slumped back while raking. Use a spade or turf edger to clean the 4 inch trough (flick the excess soil up onto the bed). Trough can be deeper for less frequent maintenance but must weigh this with health and safety concerns by considering who is accessing the garden plot as some users may trip into the trough on the way to the bed.

• During wet weather garden visitors / observers stepping on the turf edge can deform the edge depending on whether the soil under the turf goes straight down in line with the edged turf or angled so that the soil under the turf edge slopes from the turf edge toward the bed with a 4 inch deep "V" trough between the bed and turf edge.

• (8) the angle of repose for the soil in the bed when edging should be the soil's natural (and final) angle of repose so that when the soil settles and slumps, at least a 4 inch deep trough will remain.

• Below:Note in the picture below, that there are a few grass blades starting, however, re-establishing the 4 inch trough and pulling them now, will continue to control the grass problem

SUMMER AND FALL MAINTENANCE OF THE TURF EDGE

(note this is more than park operations would be able to do but individual gardeners with their vegetable plots should be able to manage)

• (1) Hedge clippers, 90 degree clippers or line trimmers are required for a weekly trim of the turf edge. Adjacent turf areas required cutting needs range from twice per week in a wet spring to once every seven to ten days during the hot summer months. Frequency of cutting depends on amount of rainfall, irrigation, fertilization and "compaction traffic" turf receives each week. Timely cutting can reduce the amount of lawn weed and grass seeds that blow into the cultivated bed area.

• (2) If the 4 inch trough and rolling of the bed's soil edge has been done properly one can expect to clean the trough i.e. flick up slumped soil on to the bed and vegetable plants 1 to 2 times per month that is about 9 to 18 times per growing season. Trough maintenance also includes biweekly removal of weeds and grass plants i.e. seeded or stolons invading the trough.

REGARDING DOUBLE DIGGING

I have done this before for vegetable and perennial beds and I find that this is an effective, albeit labour intensive method to control / remove grasses from bed if one takes the time to remove the roots / stolons of troublesome weeds while moving and intensively amending the soil. However if an edge is not maintained on the double dug bed, grasses from adjacent turf areas will invade the bed.

Cheers

Chris

• (Double digging, just needs to be a one time, (or just every few years) task, if you continue to maintain the garden bed afterwards)

• See also: Soil Day with John Slack for more information about double digging.

• Above and on the left: The Perth Dupont Community Garden has had good results from placing a 4 inch layer of limestone screening under these path way patio tiles, and adding the black plastic edging to keep the limestone screening out of the gardeners plots. (in the back ground is our raised garden bed.)

One last word: About removing the rhizomes, you need to find a technique, that allows you to find each and every rhizome! This is very important, a one or two inch piece of rhizome will make a new plant. I have found that using a standard garden shovel or spade it better that a pitchfork, for this job, as well as a lot of patience!

.