Broadleaf Weeds: Tree Friendly Control

Weeds: Symptom, Not Disease

Contrary to popular belief, weeds are actually a sign of greater problems within your lawn. Weeds flourish when site conditions are unfavorable for grass growth. Applications of herbicide can reduce the number of weeds in these locations, but unless the other issues are addressed, the weeds will keep coming back.

Weeds can flourish in conditions where grass cannot. They tolerate soil compaction, high ph, lack of nutrients, over watering, under watering, and heavy shade. There are solutions to each of these problems; don’t let anyone tell you that constant herbicide application is the only answer.

What is a Weed?

Long story short, a weed is a plant growing where it is not supposed to grow. Originally lawns were compromised of a number of different plants, including grasses, chamomile, clovers, and mosses. The combination of these things maintained a beneficial level of biodiversity, and made lawns possible with fewer inputs.

These days 100% turfgrass is the ideal, but this ideal is difficult if not impossible to maintain. In a healthy, vigorous lawn, 90-95% turfgrass is a more reasonable, and achievable goal. The small amount of weeds left will not be very noticeable in your vibrant, healthy lawn.

Not All Herbicides are Created Equal

The vast majority of broadleaf herbicides are designed to move through the soil, attacking the roots of any broadleaf plant they may encounter. This can be detrimental to the health of your valuable trees and shrubs, which are broadleaf plants.

Certain herbicides, however, work differently. Spot spraying with an herbicide which does not contain dicamba, is a viable way to help control weeds, particularly when you are starting with a lawn overrun by weeds. These micro-encapsulated herbicides will not leach through your soil, causing problems for your trees and shrubs.

All herbicides can cause damage to desirable plants if they are not used correctly, or are used as the only means of weed control. Using the following guidelines will help make sure that herbicides are being applied the right way.

• Always make sure that anyone applying herbicides to your property has their Minnesota Department of  Agriculture Pesticide Applicator License.
• Make sure that herbicides are being used minimally, and as a part of an integrated pest management program.
• Herbicides should not contain dicamba, which can cause severe damage to your trees and shrubs.
• Use herbicides in an “amine” form rather than the more volatile “ester”.
• Spot spray. Spot applications are much less likely to harm desirable plants. Spot applications also use less herbicide, decreasing the amount of pesticides put into the environment by a significant amount.

Integrated Pest Management

The best way to control weeds is to have thick, healthy grass. The creation of an environment where grass will flourish and crowd out weeds is called Integrated Pest Management, or IPM. This is a combination of cultural practices (such as watering and mowing), and services which work to improve the health and vigor of your lawn.

IPM begins with your soil. A soil test provides information about the nutrient content, ph, and organic matter content of your soil. Along with a soil test, a site analysis is important to determine what other conditions are effecting the growth of your grass. An IPM plan without these two things is incomplete, and less likely to yield results.

Aeration, seeding, soil amendment, and fertilization are the main-stays of a successful IPM program. Along with cultural practices, these are the things which determine the health of your grass.

Aeration

Aeration is a useful tool in lawns where soil is compacted, or there is heavy thatch cover. During aeration, plugs of soil and grass are removed from the soil. This enables grass roots to get more oxygen, aids in the breakdown of thatch, and fosters root growth. Soil plugs should be left on the soil. They will break down within a week or two returning valuable nutrients to the soil.

Seeding

Seeding goes hand-in-hand with aeration. The introduction of new grass varieties is invaluable to the health of your lawn. Customized seeding can provide seed blends which are designed specifically for your site conditions. Additionally, many of the new varieties which are being introduced have a greater disease and drought resistance, decreasing the water and pesticide input your lawn requires.

Soil Amendment and Fertilization

Different soils need different things, what works well in a clay soil will not work in a sandy soil. A combination of soil amendment and fertilization will provide organic matter and the nutrients that your lawn needs, creating a healthy environment which promotes thick, vigorous grass.

Cultural Practices

About 60% of having a healthy lawn can be tied to proper watering and mowing. Conversely, poor watering and mowing practices can lead to disease, weed infestation, and a high-maintenance lawn.

When mowing, always use a sharp blade; dull blades bruise and mangle grass. Beware of mowing too short, grass is at its best when it’s mowed between 2 1/2 and 3 1/2 inches. Do not remove more than 1/3rd of the grass at any mowing. If your lawn gets away from you, mow several times with a day or two in between.

Water deeply and infrequently. Frequent, shallow watering leads to lazy grass with shallow roots. Less watering leads to deeper roots and greater drought resistance.

Questions?

Don’t hesitate to contact us with any of your lawn care questions!