Weeds are a challenge, even in a raised bed garden

In the bottom two middle squares of my raised bed garden, the spinach and leaf lettuce is growing from last month, but now it appears like there are some unwanted plants as well — weeds! In just a few short weeks, our garden has been overtaken by weeds. The weed seeds came from the topsoil I purchased. Weeds are a problem when you have a garden of any size, unless you use new, sterile, soilless growing media each season. Knowing what you planted will really be important so you can be on the lookout for the seedlings, and remove just the weeds.

Seedling leaves (cotyledons) often look completely different from the first true leaves that come out later. One characteristic that can help you in figuring out if you have a weed or a plant you want to grow is by looking at the number of leaves that sprout from the seed. If the plant has one seedling leaf, it is called a monocot (monocotyledon). This includes plants like onions, corn, and grasses. If the plant has two seedling leaves at germination, it is called a dicot (dicotyledons) and includes plants like tomatoes, beans, potatoes, spinach, and lettuce. Dicots are sometimes referred to as broadleaf plants. Many times selective herbicides work on either monocots or dicots but not both types of plants; that’s what determines which plant will be killed by the herbicide or which will be resistant. Non-selective herbicides will kill both monocot and dicot plants.

Sometimes people get really upset when I call a plant a “weed.” Please remember that many plants can be designated as weeds. The simple definition is “a plant growing where it is not wanted.” So even though weeds can have desirable characteristics, when it is a plant growing where it is not wanted, it is a weed. Weeds compete for sunshine, water, space, and nutrients in the garden, and some can be hosts for diseases and pests.

As with most gardening tasks, addressing the problem early and often is the best advice. Being able to identify weeds when they are small is one of the skills that I continue to hone each growing season and it takes practice and time. Knowing what you planted and where you planted it is the first step in knowing what may or may not be growing. Virginia Tech has a nice identification guide that lets you answer questions about the specimen and points you to a possible answer.

I will be using mechanical control methods (hand pulling or a small hand shovel to remove the weeds) because it’s such a small area.   

In our commercial high tunnel operation, we use a physical barrier as our first line of defense in weed control. Wind can cause hardships with keeping landscape fabric held in place, but we use 6-8’’ long landscape pins to hold it down.

Here is information on managing weeds organically.

We have had some very chilly night temperatures which is not too uncommon here in the mountains. Our expected frost-free date is June 5th, so I’m looking forward to putting in some warm season vegetables in the coming weeks — tomatoes, peppers, green beans, and maybe a summer squash are on our list.

Weeded garden bed

By Ashley Bodkins, Senior Agent Associate and Master Gardener Coordinator, Garrett County, Maryland, edited by Christa Carignan, Coordinator, Home & Garden Information Center, University of Maryland Extension. See more posts by Ashley and Christa.

No-till gardening and weed barriers

In a mid-March post, I wrote about the advantages of using heavy-duty weed barrier fabric to smother weeds and create a no-till plant bed. In mid-June, I found myself with two beds that were starting to get weedy. The winter cover crop that had protected the soil was quickly decomposing and crabgrass and broadleaf weeds were emerging.

Weeds
Rapidly growing weeds are quickly brought under control with weed barrier fabric.

I threw on 3-ft. wide strips of the weed barrier material and after five days of very hot weather all of the vegetation was dead. Continue reading

Q&A: Is this giant hogweed or poison hemlock?

poison hemlock
Poison hemlock can be mistaken for giant hogweed

Q: I think I might have giant hogweed on my property, or maybe it is poison hemlock. How can I tell for sure?

A: Giant hogweed (Heracleum mantegazzianum) was found recently in Clarke County, Virginia, and it has raised awareness and concern about the plant – and rightfully so. The plant produces toxic sap that can cause very severe skin inflammation. We have received a lot of questions about it lately.

poison hemlock
Poison hemlock Photo: E. Nibali

What you have here is NOT giant hogweed. It is poison hemlock (Conium maculatum), which is much more common. The ferny foliage makes it possible to distinguish it from giant hogweed.

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What Can I Do About All These Weeds?

Ground Ivy
Ground ivy or creeping Charlie (Glechoma hederacea). Photo by Betty Marose

The famous quotation about the certainties of life which we all know includes death and taxes should also mention weeds! They are sprouting up all over. Even the most meticulously tended landscapes are not immune.

Where to Begin?

The first step is identification. You need to know your opponent. Control is more attainable if you know whether it is a grassy or broadleaf weed. Is it an annual, perennial or biennial? When does it germinate? Fall, spring, or summer?

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What Can I Do About My Neighbor’s Plants Coming Onto My Property?

bamboo
Bamboo. Photo: Chuck Bargeron, University of Georgia, Bugwood.org

Maryland property owners are limited to self-help when dealing with plants encroaching on their properties. This is not legal advice.

Have a neighbor who has planted bamboo or another invasive plant species near your shared property line and now that plant has started encroaching on your property? What can you do in this situation? Maryland has only one decision discussing damage from plants growing on a neighbor’s property. In Melnick v. C.S.X. Corp., the Court of Appeals of Maryland limited landowners to self-help to remove invasive plant species from growing on your property. The courts in Maryland have found that “it is undesirable to categorize living trees, plants, roots, or vines as a “nuisance” to be abated. Consequently, we decline to impose liability upon an adjoining landowner for the “natural processes and cycles” of trees, plants, roots, and vines.” (Melnick, 520-521). Self-help means it will be up to you to remove the roots, limbs, vines, and other plant debris and not the neighbor who planted the invasive plant species. A neighbor cannot seek damages in court for the damages caused by the invasive plant species.

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Black Covers Can Put Weeds to Bed… For Good

Have you experienced one or more of these garden scenarios?

  • It’s early April and chickweed, henbit and other winter annual weeds are growing so thickly in a vegetable or flower bed that the soil can’t be seen.
  • The winter rye cover crop you mowed last week is growing back.
  • You tilled and raked a bed that you couldn’t plant right away and now weeds are coming up everywhere.
  • The rainy summer weather is favoring weeds over crops so that the weeds are taking over walkways and dominating beds that you want to plant with fall crops.
  • Neighboring plots in your community garden have been abandoned and weeds are growing wild and reproducing!

I can’t bear to look… I’m going back inside

This stirrup hoe is great at removing large weeds, but brings lots of weed seeds up to the top two inches of soil where they have a good chance of germinating.

Un-controlled weeds compete with garden plants for water and nutrients, are hosts for insect pests and diseases, and can demoralize the toughest gardeners. Tilling, pulling, chopping, and hoeing are all fine weed control techniques under the right conditions, but they also disturb soil allowing even more weed seeds to germinate and flourish.

There’s another way: occultation. The common dictionary definition is “an event that occurs when one object is hidden by another object that passes between it and the observer.” For gardeners and farmers, it’s covering the soil to create a dark, warm, moist environment. In 2-4 weeks, this no-till technique can:

  1. smother and kill young weeds
  2. smother larger weeds and grasses
  3. accelerate the decomposition of mowed cover crops and weeds
  4. promote the germination of weed seeds and then smother the seedlings

Weed barrier pinned down over a bed filled with winter annual weeds. It was ready to plant in two weeks. Tough perennial broad-leaf weeds and grasses may be weakened but not killed.

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Spring Lawn Care: How to Deal with Weeds and Bare Spots

forsythia shrub in bloomWith spring gardening season right around the corner, lawn questions have been rolling into the Home & Garden Information Center (HGIC). Here I’ll address some of the most common questions about weeds and overseeding.

Dealing with Winter Weeds

chickweed
Chickweed

In late winter/early spring, we typically see winter annual weeds in thin, under-fertilized, wet, or shady areas. These weeds germinated in the fall and will die as the weather warms up later in the spring. In my observations, this has not been a particularly bad year for winter annuals. They are favored by wet, mild winters and I think we had just enough “bitter cold” in January and a fairly dry stretch through December and January to reduce populations.

Typical winter annual weeds include chickweed, henbit, purple deadnettle, and shepherd’s purse. Options to address these winter annual weeds include hand pulling, spot spraying with a broadleaf herbicide, or waiting until they die once weather climbs to the 60’s and 70’s on a regular basis. For perennial weeds like dandelion which will start to re-emerge later this month, hand-pulling or spot spraying are the best methods for control.

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