Weed Control Methods Used by Professional Landscapers

Most articles about how professionals control weeds are about spraying. This one isn't. White Shovel doesn't spray or apply weed killers; we take weeds out and change the ground so they have a harder time coming back. That's the method below, in the order we work, with one short section at the end for homeowners who use weed killers themselves.

Start With Why the Weeds Are Winning

Weeds don't take over healthy, covered ground. They take over bare soil, thin grass and beds with gaps between the plants, anywhere sunlight reaches the dirt. So before anything gets pulled, walk the yard and look at where the weeds are, not just what they are.

• Bare or thin spots in the lawn, often where water sits or the ground is packed hard.
• Wet spots. Nutsedge, the bright green grassy weed that grows faster than your lawn, loves soggy clay. If it's thick in one part of the yard, that part probably stays wet.
• Bed edges where Bermuda grass creeps in from the lawn under the mulch.
• Old mulch that has broken down into a thin layer of soil, which is a perfect seedbed.

In North Alabama, compacted red clay is behind a lot of this. Water runs across it instead of soaking in, grass roots stay shallow, and weeds that tolerate tough ground move into the gaps.

Get Them Out at the Root

Pulling works when you get the whole root. Snap a weed off at the soil line and most perennials grow straight back.

• Pull after a rain or a good watering, when the soil is soft. In dry clay, roots break.
• Dig taprooted weeds like dandelions with a narrow hand weeder, straight down beside the root, and lever them out.
• Dig nutsedge, don't pull it. Nutsedge spreads from small tubers (nutlets) in the soil. Pulling the leaves leaves the nutlets behind, and each one can send up a new plant. Take the soil around it out with a trowel.
• Follow Bermuda grass runners back to where they came from. Leave a piece of runner in the bed and it roots again.
• Use a stirrup or hula hoe for a bed full of small annual weeds. It slices them just under the surface without turning up a fresh batch of seeds.

The rule that matters most: get weeds out before they flower. Once they set seed, you're weeding the same bed next year.

Cover the Soil

Weed seeds need light to sprout. Cover the soil and most of them never do.

• Mulch 2 to 3 inches deep in beds. Thinner lets light through; much deeper holds water against stems and roots. Keep it pulled back an inch or two from trunks and stems.
• Top it up as it breaks down. Bark and hardwood mulch turn into soil over a couple of seasons, and that new soil on top is where the next weeds sprout.
• Buy clean mulch. Cheap mulch and bagged soil can bring weed seeds with them.

Landscape fabric: where it makes sense. Fabric works under rock, gravel and river rock, where nothing is meant to grow and the stone never breaks down. Under bark mulch it works against you: the mulch rots into a layer of soil on top of the fabric, weeds root into it, and the fabric keeps organic matter from reaching the ground underneath. So we use it under stone, and use mulch and plants to cover soil everywhere else.

Plant Densely

The best long-term weed barrier is plants you actually want. When shrubs and perennials grow together, they shade the soil and leave weeds nowhere to start. Space new plantings for their size at maturity, not the size in the pot, and fill the gaps in between with a groundcover. Liriope and mondo grass both handle North Alabama heat and clay and fill in thickly once they're established.

In lawns, the same idea means thick grass. Mow high, and never take off more than a third of the blade at once. Taller grass shades the soil. Where the lawn is too thin or too weedy to come back, new sod is often faster and cheaper in the end than fighting the old turf.

Fix the Conditions Underneath

If a bed keeps filling back in, something is feeding the weeds. Usually it's one of these:

• Water that sits. Fixing the drainage is what finally ends a nutsedge problem in a wet corner. Pulling alone won't.
• Compacted ground. Loosening packed clay and working in organic matter lets grass and plants root deep enough to hold their own.
• Gaps in the planting. Bare ground between plants gets planted with something, or it gets weeds.

Starting a Bed Over? Try Solarization

For a bed that's more weed than anything else, solarization cooks the weeds and many of the seeds in the top of the soil without any chemicals. Clear the bed, water it well, and cover it with clear plastic sheeting, edges buried so it stays sealed. Leave it through 4 to 6 weeks of the hottest part of summer. Clear plastic works better than black, because it lets the sun heat the soil underneath. Then plant and mulch without digging deep, so you don't bring buried seeds back to the surface.

If You Use Weed Killers Yourself

Some homeowners use herbicides, and a few basics keep them from doing more harm than good:

• Pre-emergents stop seeds from sprouting and do nothing to weeds that are already up. Timing is everything: for crabgrass, they go down before the soil warms to about 55°F in late winter.
• Post-emergents kill weeds that are growing. Selective products target certain weeds and spare the grass; non-selective ones like glyphosate kill whatever they touch, including your shrubs.
• Read the label and follow it. The label is the law on how a product is used.
• Spot-treat single weeds instead of spraying whole areas, keep spray off windy days and away from ornamentals, and don't spray right before rain.

No product fixes the reason weeds keep coming back. Bare soil, thin beds and wet spots will fill with weeds again whatever was sprayed last season.

Final Thoughts

No method keeps every weed out for good. But weeds are much less of a fight when you work in this order: find out why they're winning, get them out at the root, cover the soil, plant densely, and fix the wet or packed ground underneath. Pull the odd weed early, top up the mulch once a year, and a bed that used to take every weekend takes a few minutes.