Lawn Care, Ants, and Asparagus, Oh My!

***Insert a consulting call I had today in which George and I discussed Lawn Care, Ants, and Asparagus. ***


Dear George,

It was good to talk to you today about your asparagus and the problems you have been having with the ants.  As discussed, here is the information on controlling the weeds in your asparagus bed and taking care of those pesty ants.

Weed management in asparagus can be divided into two periods: stand establishment, which lasts about 2 years, and mature plantings. Weed control during stand establishment is complicated in asparagus by the fact that three methods of establishment are used: direct seeding, transplanting seedlings, or transplanting dormant crowns. During stand establishment, tailor weed management techniques to the establishment method. If weeds are left uncontrolled during this period, a weak asparagus stand can develop and limit the potential of the bed for the rest of its stand life. Producing a uniform, vigorous asparagus stand and maintaining it in this condition can mitigate most weed control problems. Asparagus is a very good competitor with most annual weeds when it is a mature fern, especially if the stand is uniform and vigorous.

Once established, an asparagus bed has a stand life of from 5 to 20 years. At first, in newly established beds, annual weeds are the main problem, but as time passes, perennial weeds often become the major concern. These perennial weeds include yellow nutsedge, bed bindweed, swamp smartweed, johnsongrass, and bermudagrass. If perennial weeds become established, they can be troublesome throughout the growing period by reducing crown vigor and density and ultimately asparagus yield and quality. Perennial weeds are difficult to control culturally or chemically without injury to the asparagus, therefore prevention becomes a major tool in combating these weed pests.

To help prevent infestation of the bed by perennial weeds, be sure that seeds, tubers, stolons, rhizomes, and rootstocks of perennial weeds are not moved into asparagus beds with planting materials or on cultivation equipment. If spot infestations of perennial weeds are noted in the bed, mark the area with flags and mechanically remove the infestation. Following removal, monitor the area for at least 2 to 7 years to make sure that reinfestation from propagules or seed does not occur.

Established asparagus beds are harvested from early spring through early summer. Spears, which develop from the underground crown, are cut on a 1- to 3-day cycle, depending on temperature. During the harvest period, spears provide virtually no shade to reduce weed competition. Annual weeds can be a problem in established stands at this time because the beds are open and exposed to light. It is most important to have beds weed-free to facilitate harvest and increase soil temperature.

Preemergent herbicides can be applied either pre- or post-cutting to control many of the annual weeds that cause problems in the crop. On the other hand, monitoring for perennial weeds must be carried out throughout the year and treatment made as soon as they are detected. Initially, perennial weeds tend to develop at the head and tail of beds; spot treat infestations immediately with a foliar herbicide to prevent their spread into the bed.

After the last harvest of the season, asparagus spears are allowed to grow into the fern stage, during which the asparagus plant replenishes the carbohydrate supply in the crown for the next season. The period between harvesting spears and allowing the spears to grow into ferns is a good time for controlling both annual and perennial weeds. Also light tillage can be utilized and some herbicides can be applied in a timely manner. Once the spears have grown into ferns, cultivation and hand removal of weeds during the fern stage is difficult because equipment movement is restricted due to the dense fern growth. However, dense fern growth restricts light thereby minimizing much of the late emerging annual weed growth.

Weed management is most effective when herbicides are used in conjunction with cultural practices. Cultural practices such as proper bed selection, fallow treatment, cultivation, and hand removal help to improve herbicide performance by leaving fewer weeds; therefore a combination of both cultural and chemical control methods can give the best overall result.

Herbicides are often used in sequence or in combination to broaden the weed control spectrum; a single herbicide will seldom control all weeds present. To avoid a buildup of resistant weeds, use preemergent herbicides in combination or alternated with another preemergent herbicide.

Paraquat (Gramoxone Extra) and glyphosate (Roundup) can be used as preplant or preemergent treatments to control emerged weeds before planting or before asparagus emergence. Make sure the emerged asparagus is not contacted by these herbicides or the plants will be killed.

During the first 2 years after planting, the asparagus plants become established. Weed control is critical to the long-term well-being of the crop during this period, and it relies on both cultural and chemical controls.

For all three methods of stand establishment, planting beds are used and beds can be lightly cultivated several times during the season to throw soil onto the bed tops, thus keeping weed competition to a minimum.

Direct Bed Seeding. In direct seeding, asparagus is seeded into raised beds that may be cultivated during stand establishment to control weeds in the furrow and bed shoulders. The seedling asparagus is slow to emerge, requiring from 14 to 21 days. Once emerged it continues to grow slowly and is not competitive with most weed seedlings. This emphasizes the need to plant into beds that have a low soil weed seedbank or that have been fallow irrigated and cultivated to reduce the weed seedbank. If it is necessary to remove weed seedlings from the rows of seedling asparagus, this can be done with herbicides or by hand removal. Weed management at this stage is important in order to establish a uniform, competitive asparagus stand. Control weeds for the first 3 to 4 months in seedling asparagus until a heavy fern cover is established.

Linuron (Lorox) controls a broad spectrum of broadleaf and grass weeds and has both soil and foliar activity. Apply linuron as a directed spray to minimize contact with asparagus foliage when asparagus seedlings have from 6 to 18 inches of growth.

Sethoxydim (Poast) is used for controlling most annual grass species, except annual bluegrass. It is also effective in the control of some perennial grass species, however, more than one application is necessary. Its effectiveness requires that grasses not be under moisture stress. Later growth stages of annual grasses are more difficult to control.

Fluazifop-p-butyl (Fusilade) is a selective systemic grass herbicide that must be applied before grasses are 3 to 4 inches tall for best control. Asparagus seedlings are relatively tolerant of fluazifop, which can be applied as a broadcast application.

Transplanting Seedlings. Planting of 10- to 12-week-old transplants hastens the establishment process compared to direct seeding. Transplants are planted into trenches and usually sprinkler irrigated. This procedure allows weeds to germinate within the planted area. The young asparagus seedling is a poor competitor; thus early weed management is essential for plant survival and growth. As with direct-seeded asparagus, it is necessary to control weeds until a heavy uniform fern cover is established. The same materials used for direct-seeded asparagus can be used for transplanted seedlings.

Crown Planting. Crown planting is done when the asparagus crowns are dormant. The crowns are set into trenches and covered with 2 to 4 inches of soil, followed by rainfall or furrow or sprinkler irrigation to settle the soil around the crowns. Weed emergence soon follows, often before asparagus emergence. Rapidly growing weeds must be removed from within the planted beds. As the asparagus grows, the furrow and sides of the beds can be cultivated, which throws some soil onto the bed tops. This soil fills in around the plants and provides some weed control as small weed seedlings may be buried. As with the previous two methods of stand establishment, timely cultivations and hand removal of weeds or herbicide treatments are needed during the first season until a uniform fern cover is produced.

Paraquat (Gramoxone Inteon) is a contact herbicide that is effective against both grasses and broadleaf weeds and must be applied before asparagus spears emerge. It is most effective when applied as a broadcast application to weeds that are in the two- to four-leaf stage.

Linuron (Lorox) can be used on crown-planted seedling beds to control a broad spectrum of broadleaf and grass weeds and has both soil and foliar activity. Use linuron as a directed spray to minimize contact with asparagus foliage when asparagus seedlings have from 6 to 18 inches of growth.

Diuron (Karmex and others) may be used in the San Joaquin Delta only on high organic matter or clay content soils. It is a broad-spectrum preemergent herbicide that is useful in controlling emerging annual weeds; however, it is not very effective in the control of common groundsel, sowthistle, volunteer cereals, and wild oats.

Fluazifop may be applied for grass control after the asparagus spears have emerged. It is most effective when applied before the grasses are 6 inches tall.

ESTABLISHED ASPARAGUS. The term “established asparagus” refers to plantings that are 2 or more years old. Once crop plants are established, focus weed management efforts first on limiting establishment and spread of perennial weeds, which can reduce the vigor and quality of the asparagus stand, and second on controlling annual weeds to avoid competition during the cutting season.

Weed control in established asparagus is only possible during a relatively short window of opportunity that lasts about 4 months. This period begins with preharvest cultivations, when beds are tilled and shaped before the harvest season. It also includes the harvest period, when shallow cultivations can be used to control weeds; limit cultivation to the furrows, however, because cultivation on the bed tops will interrupt harvest for a period of up to 10 days. The postharvest cultivation, which is possible until the fern limits mechanical activity, is the last chance during the growing season to control weeds by cultivation; after this time the asparagus fern becomes too tall to permit cultivation. Perennial weeds can be difficult to control because of the relatively limited opportunity to cultivate.

Preemergence (When spears are not present). Glyphosate (Roundup) and paraquat (Gramoxone Inteon) may be used on established beds before spears emerge to control newly emerged annual weeds. Asparagus emerged at the time of application will be injured by these herbicides and spears will be unmarketable.

Metribuzin (Sencor) has preemergent activity and postemergent activity on newly emerged annual weeds. If the bed is to be cultivated or rotovated, apply after bed preparation. Irrigation or rainfall is necessary to activate this herbicide.

Diuron (Karmex and others) is useful for the control of many emerging annual weeds, but does not control common groundsel, sowthistle, volunteer cereals, and wild oats. Apply it as a band or broadcast application to weed-free beds and incorporate it mechanically or with irrigation if rainfall does not occur. Do not use it on soils with less than 2% organic matter; use lower rates on coarse-textured soils.

Flumioxazine (Chateau) is useful for the control of a wide-spectrum of broadleaf weeds. Apply it no less than 14 days before spears emerge and before weeds emerge, or burn the weeds back with a tank-mix material. Requires 0.25 inch of rainfall or irrigation to activate.

Halosulfuron (Sandea) can be applied before the cutting season to control broadleaf weeds. Do not use an adjuvant with sprays applied before the harvest period.

Napropamide (Devrinol) is useful in the control of winter annual weeds, such as common groundsel, which are difficult to control with other asparagus herbicides. It has no postemergent activity and should be used after bed preparation before weeds emerge. Napropamide requires shallow mechanical incorporation (one to two inches deep), and if rainfall does not occur, it must be irrigated.

Trifluralin (Treflan and others) is active in the control of many grasses and broadleaf weeds with the exception of those in the sunflower, mustard, cheeseweed, and legume families. Use trifluralin before spears emerge or after cutting but before ferns develop. It has no postemergent activity on weeds and must be mechanically incorporated immediately after application two times in opposite directions with disks or rolling cultivators or one time with a power-driven incorporator. Can suppress the growth of Bermudagrass if applied at this time. Will also suppress bed bindweed at high label rates.

Linuron (Lorox) can be used before harvest. Linuron has a broad spectrum of annual weed control activity. It also has both foliar and soil activity. Its residual soil activity is shorter than other residual asparagus herbicides. This makes it a better choice to use in the last season of an asparagus planting to avoid long-lasting soil residues that could affect succeeding crops. See herbicide labels for plantback restrictions.

Postemergence (After spears emerge). Dicamba (Banvel) is useful for the control of annual broadleaved weeds and troublesome perennials, such as bed bindweed and swamp smartweed. It is applied immediately after spear cutting or as directed sprays to avoid spear and fern contact. Spears that are twisted or malformed as a result of treatment should be cut and discarded. Be sure to comply with all state and county regulations as to proximity to susceptible crops and other restrictions regarding their use.

Linuron (Lorox) can be applied immediately after cutting, but do not harvest within one day after application.

Halosulfuron (Sandea) can be applied during the cutting season to control broadleaf weeds. Do not use an adjuvant with sprays applied during the harvest period.

The grass herbicides sethoxydim (Poast) and fluazifop-p-butyl (Fusilade) can be used on emerged spears. Both have a one-day preharvest interval and work best on actively growing grasses.

Postharvest (Before or at the onset of the fern growth). Halosulfuron (Sandea) can be applied following the cutting season to control broadleaf weeds and yellow nutsedge. A nonionic surfactant or crop oil concentrate may be used with postharvest applications only.

Diuron (Karmex and others) can be used during the postharvest period, but care needs to be taken to not exceed the seasonal limitations.

Linuron (Lorox) can be used during the fern stage by using sprays directed to the base of the fern.

Metribuzin (Sencor) can be used following the final harvest but before spears emerge that will form the fern.

Trifluralin (Treflan and others) can be mechanically incorporated following harvest and before fern growth to suppress grasses and broadleaf weeds.

The grass herbicides sethoxydim (Poast) and fluazifop-p-butyl (Fusilade) can be used on emerged spears and both have a one-day preharvest interval. They all work best on actively growing grasses.

Glyphosate (Roundup) may also be used as a postharvest treatment when all remaining spears have been removed (clean cut). It is useful in controlling emerged annual and perennial weeds; use higher rates of application to control perennials. Direct contact of the spray with asparagus fern can cause serious injury. Glyphosate is useful for spot treating perennial weeds around the edges of asparagus beds to prevent these weed infestations from spreading into the bed on incorporation and cultivation equipment.

I realize that for each of the three methods there is a long list of chemical products that can be used.  If you plan to grow your asparagus organically or do not want to mess around with chemicals, Established beds should be mulched with a weed-free straw or some other type of organic mulch in the early spring, just a shoots are starting to emerge. The few weeds that manage to grow up through the mulch can then be pulled out by hand or dug out if it is a perennial weed. Some sources suggest applying salt to the soil, as asparagus is more tolerant of salt than a lot of other plants. Salt does control weeds, but it can wash into other parts of the garden and damage less salt tolerant plants. It also breaks down the soils structure, so mulching and hand pulling are really your best bet.

As for ants, there are a number of natural home remedies you can use, including planting pennyroyal in the area where the ants are in the yard or around the home, herbal pesticides (available at big box stores and garden centers), and Borax.

Borax will actually kill many different types of insects by dehydrating them until they are nothing but little shells. While it will not destroy a nest of ants unless you take it to them directly (sprinkle it on the hill/nest), it will get rid of any foolish enough to come into your home.  It can usually be found in the laundry detergent section of store, although some Wal-Marts put it with their dish detergent.  Depending on the brand you purchase, it may be “mule trained”.  Either version/brand is okay, just so long as it is Borax.

Target areas of the house that need to be treated. Identify problem areas. These will often be the areas of the house where ants have access to food, like the kitchen and potentially the game room, or water, like bathrooms and other sink areas. You may also have some issues with bedrooms particularly if they have adjacent bathrooms or if you have teenagers that like to snack while they study.

Sprinkle a thin line of borax along the back edges of counters and under cabinets if need be. You can do this by pouring it, but generally it is easier to use a small scoop. The borax just needs to be along the very back of the counter, and you do not need a lot of it. A very thin line is easy to avoid when you are using the counters and will be enough to attract the ants’ attention so that they will eat it.

Make sure that there is borax on the window sills or other potential entrances to your home. Often if ants find something tasty near the entrance to your home, they will change their entrance “plan” and simply consume whatever is closest. By making the borax available right at your doors and windows, they may eat it and then leave rather than coming inside. The end result is the same either way, but you increase your odds of success by placing the borax near where the bugs are coming in.

Make a small trail of Borax around the edges of all rooms. You do not need any more along the edges of the rooms than you do in any other part of the house. Just use the scoop to draw a thin line around the room. If you have carpet, then you can just follow the line between the wall and the carpet. If you have hardwood floors then simply trace around the edge of the molding.

Once your ant problem is solved, you can vacuum or sweep up the borax to keep it from simply creating a mess on your floors as it spreads.
I hope this helps to answer your question.



© Mertie Mae Botanics LLC and Horticulture Talk!, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mertie Mae Botanics LLC and Horticulture Talk! with appropriate and specific direction to the original content.

3 thoughts on “Lawn Care, Ants, and Asparagus, Oh My!

  1. I have a number of fire ant mounds in my Asparagus and i’m not sure what to do about them. I don’t want to damage the crop or put something on it that will be harmful to people. Suggestions?

  2. Pingback: Knock ‘em Dead: Tried and True Way to Get Rid of Ants | Horticulture Talk!

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