What is a weed anyway?
We have heard people say, “a weed is an unwanted plant” or “a plant out of place.” Yet, if a beautiful flower appears naturally in our garden, we call it a volunteer, and might even go to the trouble of transplanting it. So, categorizing something as a weed must have something to do with beauty, or lack thereof. Weeds are a natural part of our eco-system and all serve a purpose. They are tough, hardy plants that have adapted over time to their environments. On the other hand, our gardens are filled with delicate hybrids and pampered with regular watering and supplemental nutrients. So, it is no surprise that weeds appear like magic.
But where do they come from? Recently, I regraded a property and added new topsoil, but the sod was delayed. It was amazing how quickly the yard was covered with tiny little weeds from seeds that had hitched a ride with the topsoil – just waiting for the right combination of sunlight and water. Did you know that broadleaf weed seeds can remain dormant for decades? They can also be brought to us by the wind, the birds, or from weeds in your neighbor’s yard that creep under your fence.
According to The Old Farmer’s Almanac, “Of approximately 250,000 species of plants worldwide, only about 3% behave as weeds that we don’t want in cultivated areas. Weeds aren’t inherently bad.” But, they compete with other plants for sunlight, nutrients and water. They can also harbor disease and unwanted pests. Before you can eliminate them, you must know your enemy: what it likes, what it doesn’t, and especially how it reproduces. Like all living things—including us—weeds have defense mechanisms to protect themselves from predators. Some have thorns, some are poisonous, some break off and grow back from a tap root, some send out rhizomes that when cut are able to form new plants, and some use camouflage for protection by hiding near and under wanted plants that look like they do.
The best way to get rid of them is to not let them grow in the first place. As they say, “An ounce of prevention is worth a pound of cure.” Applying a pre-emergent like Preen and installing two inches of mulch can result in a weed-free summer. Mulch can also be used to smother small existing unwanted guests. The most important thing to keep in mind is: the early bird gets the worm. In other words, never, never let them go to seed. You’ve got to nip this in the bud—no pun intended! And, be diligent. Pluck out the newcomers each morning as you walk around your garden with your morning coffee.
Pulling is by far the best, albeit most onerous way to rid your garden of unwanted plants, a/k/a weeds. But pull them carefully. Don’t pick them. You have to get the root. If you don’t, they will return—with a vengeance. Just like a professional contractor, be sure to use the proper tool. If they are in their infancy, simply loosen the soil and plow them under.
The best way to control weeds in your lawn is by choking them out. Keep your grass healthy and thick by applying fertilizer and crabgrass preventer. Test your soil to determine if it could also benefit from the addition of lime. Weeds love bare patches of soil; don’t give them any.
Make sure to keep your beds tidy especially if you have prolific seeders like Norway Maples (Acer platanoides) or Japanese Snowbell (Styrax japonicus). Clean up the “seeds” also known as spinners and nutlets. If you don’t, you will have so many seedlings next spring you could start a tree farm.
You can also eat weeds—or least some of them like bittercress, chickweed, clover, dandelion, dead-nettle, and purslane, just to name a few. Be sure to identify them properly, as many weeds are poisonous. Also, wash them thoroughly to remove any pesticides that may have been applied.
Plain boiled water can also kill weeds. So can natural substances like white vinegar, salt, rubbing alcohol, or even a little bleach diluted in water. Or, you can make your own herbicidal soap by combing vinegar, salt, and dish soap. Natural solutions are far better for the environment, but they are not selective and will harm ornamental plants if you’re not careful. If all else fails, and you must resort to chemical warfare, go easy. Don’t use anything stronger than what you need. There is no need for Roundup® when Weed B Gon® will do, and please read the labels carefully.
The Most Wanted List
The one that pops
Hairy Bittercress (Cardamine hirsute) is actually a delicious wild mustard plant. It is one of the earliest annual weeds to appear but will disappear once temperatures climb. It starts out as a basal rosette, then sends up three- to nine-inch stems that develop tiny, white flowers. After the flowers fade, it develops seed capsules known as siliques that pop seeds out, up to three feet around the plant. It likes cool moist soil and is easy to pull. Just make sure you use a tool to get the tap root and pull it before it goes to seed.
The one that looks like grass
Yellow Nutsedge (Cyperus esculentus) has v-shaped leaves that are yellower and thicker than grass. If you roll it between your fingers, you will understand the old saying “sedges have edges and grasses are round.” Since it grows faster than grass, it is easy to spot and maxes out at about six inches. It is a perennial that appears in spring and dies back during the heat of summer. It likes all types of soil and sports straw-colored flowers. It reproduces every four to six weeks by three different means: seeds (the least problematic), rhizomes that grow eight to 14 inches below the surface, and nutlets that can remain dormant for up to 10 years. When they germinate, they will not only grow up through mulch but can pierce landscape fabric as though it weren’t there. One plant left unattended can turn into a patch 10 feet or more in diameter. Do not pull this weed. If you do, you will see tiny little roots and think you got it, when in reality, the rhizomes and nutlets were left undisturbed. The bigger frustration is that most herbicides are ineffective against this imposter because it is a sedge, not a broadleaf weed or a grass. You can try digging it up, but make sure you go down at least 10 inches. Targeted herbicides like Sedgehammer®+ (halosulfuron) or Ortho® Nutsedge Killer (sulfentrazone) are unfortunately the usual solution.
That huge thing with the berries that stains your clothing
Pokeweed (Phytolacca Americana) is a large, poisonous weed that grows four to 10 feet tall by three to five feet wide. It has a thick reddish-purple stem and green leaves as well as a thick, fleshy taproot that can reach four inches wide and 12 inches deep. White flowers appear from early summer to fall followed by dark purple berries. It likes full sun to part shade. When the plants are small, pulling is an effective means of removal. As it grows, you will need a shovel to dig it out. Cutting it off below its crown may also do the trick.
The one that looks like Morning glory vine
Bindweed (Convolvus arvensis) looks pretty when it blooms with its white or pink flowers, but you will be sorry if you leave it alone long enough for it to do so. It is an aggressive vine that grows over four feet long, twisting its way around existing plants and sometimes causing them great distress. If left unattended, it can smother your garden. It reproduces by sending out rhizomes and generating seeds that can last up to 30 years. This is another weed that requires persistence to eliminate. Repeated cutting at the base of the plant will weaken it eventually or you can carefully apply an herbicide.
The one that looks like chives
Onion grass (Allium canadense) has thin leaves and grows in clumps. It is a cool weather plant appearing in spring and fall. It reproduces by seed and bulblets. Don’t simply try to pull it out. Either the green tops will break off or you will surely leave behind some baby bulblets because they are designed to break away from the mother plant and stay in the soil. Rather, dig it up (preferably after a rainstorm) being careful not to shake off the soil. Dispose of the whole clump. If new shoots reappear, dig them up or treat them with an herbicide like Ortho Weed B Gon® MAX.
The one that breaks off
Creeping Woodsorrel (Oxalis corniculata) resembles clover but is green to purple and flatter. It is a perennial and grows in full sun or shade. It is a frustrating, tenacious, persistent pest that takes dogged determination to eradicate. Once you understand how it reproduces, you will know why. Most plants have only one way to replicate themselves—this one has four! It sends out interlocking rhizomes that break when you try to dig them up. Each piece left behind can turn into a new plant. Those rhizomes also develop tiny little bulbils that form new plants. In addition, it produces seeds (up to 5,000 per plant each season) in tiny little capsules (resembling okra) that are ejected up to 10 feet from the mother plant. Lastly, every place a stem touches the soil, it can re-root, forming a new plant. It often hides under other plants, becoming intertwined with their roots. So, even though herbicides will work to some extent, you may end up damaging other innocent bystanders. Pulling will not solve your problem either, because the rhizomes break off so easily. The only solution is to dig up the area around the plant and sift the soil. It is a time-consuming process that can take many years to complete.
Public enemy #1
Poison ivy (Toxicodendron radicans) I predict when the world comes to an end, poison ivy will still be thriving! The leaves grow in groups of three, are both shiny and dull, emerge red, turn green then back to red in the fall. Each one can be a few inches long or as big as your hand. Poison ivy has many forms, from a small plant to a large shrub or a climbing vine and prefers semi-shade. It reproduces by seed and rhizomes. The problem is the oil the plant produces, called urushiol, which is found on its leaves (even dead ones), stems and roots and can last up to 10 years! We all know the horrible itchy rash it causes when it comes into contact with your skin. What you may not know is the oil can be transferred via clothing, tools, pets, or anything it touches. Your pets may spread it to your carpets, furniture and even your bed linens.
If the plant is small, protect yourself with a product like IvyX™ or Ivy Shield™, wear disposable gloves and pull it. Small patches can be removed by digging them up. Be sure to clean your tools afterward. Products like Ortho® GroundClear® Poison Ivy & Tough Brush Killer are usually necessary to eliminate larger infestations. Just never, ever burn it. Burning releases urushiol into the smoke which enters your lungs and can land you in the hospital! If you are unlucky enough to come into contact with this plant, wash immediately with Dial soap or Tecnu® and cold water. Most importantly, remember the old adage: Leaves of three, let it be.