Garden Weed Management: Using Pulled Weeds for Mulch

Pile of Bindweed. Use as Mulch? Think Again!

Andrea Cummins, Extension Agent at neighboring CSU Douglas County Extension, has this to say about using your weeds as mulch.  Be careful. You might be making your weed problem worse!

“Afternoon July thunderstorms have brought an onslaught of weeds in gardens and open space all along the Front Range. Soils too dry for seed germination this spring now have enough moisture to sprout weeds. Weeding practices may actually worsen the problem. Leaving pulled weeds on the soil surface is advocated by some as a way of mulching. Weeds dry out and die and the debris forms a mulch.

It is important to identify the weeds pulled for mulch. Some weeds can be pulled prior to setting seed and left in place with no danger of returning.Examples include: salsify, annual sowthistle, groundsel, and prickly lettuce.

Weeds such as bindweed, purslane, prostrate spurge and prostrate knotweed can root from a very small piece of stem or root. Gardeners should not leave these weeds on the soil for mulch, instead dispose of them in the trash.”

Violets and Ground Ivy in the Lawn by Elaine Lockey

Common blue violet

 Is it a flower or a weed?  Well that answer is truly in the eye of the beholder. The common blue violet, Viola species, seems to be such an innocent little plant when first appearing in your lawn but can become a very difficult plant to control if allowed to spread.  It can make a stunning ground cover with its pretty blooms in early spring and heart-shaped green leaves. It is generally found in woodlands and enjoys shady to partly sunny moist areas. However, it can also adapt to dry areas once established.

Ground ivy, also known as creeping Charlie, Glechoma hederacea, offers lush dark green leaves that are rounded with toothed edges and small funnel-shaped purplish-blue flowers in the spring.  This perennial belongs to the mint family and has square stems and a pungent odor when the leaves are crushed.  Ground ivy and wild violets can sometimes be confused when flowers are not present.

Both plants spread via seed from blossoms, branching rhizomes, and creeping roots.  With so many options to expand their range, it’s easy to see how they do so very easily.  These plants will simply spread out of your landscape beds and into your lawn.  Removal of them is a little more complicated.  Hand-pulling often just results in a lot of time and effort and broken off plants as they have extensive root systems.  Herbicides are usually recommended.

Ground Ivy in turf

If violets or ground ivy are in your lawn, you’ll need to use a broad-leaved herbicide only.  This type of herbicide will not harm your established lawn but can harm neighboring desired plants if the spray drifts.  Caution is highly recommended by using herbicides on very calm days and following all label directions.
 

A herbicide containing triclopyr, 2,4-D, MCPP, dicamba, or sulfentrazone is recommended for success in control, with triclopyr showing the best results. The best time to apply this spray on perennial weeds, such as violets and ground ivy, is September to early October.  Plants are storing energy reserves in their roots and stems for winter and the herbicide will be able to reach all parts of the plant via the food reserves.  You might not see immediate results but should see some impact in the spring.  Multiple treatments may be necessary. If you only have a few violets in your lawn spot-treat those areas, instead of applying herbicides to your whole lawn.
 

A healthy lawn is also the best defense against these and other weeds.  Proper mowing, fertilizing, watering, and aeration practices will provide you with the greatest success in conquering weeds.  The best defense I’ve discovered though is a healthy acceptance of a not so perfect lawn.  Consider lawn violets or ground ivy as a pretty addition and if you don’t spray them with herbicides you can incorporate them into your next salad. I am amazed at the number of things you can do with these plants from foods to vinegars to cosmetics.  There’s always a bright side right?

common violet photo by sierrapotomac.org

Use Caution When Pulling Myrtle Spurge By Joyce D’Agostino

For the most part, weeds in our landscape are harmless and are just an annoyance that cause us a lot of work in pulling and removing. There is one weed however that can be found in our local landscapes that requires some caution.

Myrtle Spurge (Euphorbia myrsinites) is considered a Class A noxious weed and can be found throughout the state. It must be eradicated.  It is a violation of the Noxious Weed law to grow this plant.

This information produced by Jefferson County has a good summary and pictures of this weed: http://www.co.jefferson.co.us/jeffco/weed_uploads/myrtspur.pdf

As you weed this spring, keep an eye out for Myrtle Spurge in your garden. The issue with this particular weed is that is produces a milky sap that can cause burns to skin. Use gloves to pull it, don’t touch your eyes or skin and dispose of it carefully.

Poisonous Weeds

Water Hemlock

A couple of weeks ago I blogged about eating the weeds in your garden.  Here's a cautionary article about being sure those weeds are the edible varieties.  There's poison in them there woods!! Be very careful when eating anything wild.


Horticulture - Poisonous Weeds

Eating Weeds

Tired of weeding? Try eating them instead! Here's a cool old article about growing and eating the weeds in your garden!

PlantersPlace.com | Horticulture Magazine Articles

Noxious Weeds

Spending the day weeding usually puts me in a noxious state of mind. Especially when I notice that many of my weeds are on "the list".  Yes there is a list.  Here's a great web site that will tell you all about "them".

"Weeds are native or non-native plants that are unwanted in a particular area at a particular time.  Change the area and the time and the plant might be desirable or even cultivated.
     When weeds become so wide-spread that they threaten crops, livestock, or native species, they may become more than just a "weed".  They may then find themselves on a state list of plants to be attacked in a methodical manner with state support.  They might then be termed "noxious weed",  "invasive species", "exotic species", "alien species", or some similar term as set forth in law by each governing body.  
     These noxious weeds find their way into new areas via boats, planes, soles of shoes, imported animals and agricultural products, etc.  With increasing frequency, these most dangerous of  weeds are causing the extermination of native flora and fauna from larger and larger areas."

Read here for more information:

 Noxious Weeds

Are You Unknowingly Harboring a Noxious Weed in Your Garden? by Donna Duffy

It’s easy to get hooked on flowers that are easy to grow, especially those that seem to be refreshingly trouble-free. Unfortunately, some of these qualify as noxious weeds, and their rapid growth causes a multitude of problems. These undesirable plants reduce habitat for wildlife and native plants, alter riparian areas, and cause problems in agricultural lands. Colorado Noxious Weeds are illegal to grow, even though they may be available on the internet and in some “big box” stores. Following are three Noxious Weeds to watch out for, and native and non-invasive alternatives you can grow in their place.

Noxious Weed: Purple Loosestrife. Here are some good alternatives:

Mojave Sage (Salvia pachyphylla) – Plant Select®, 2005:  Mojave Sage is an intensely aromatic, evergreen foliage with great substance. The silver-green leaves set off persistent flowers.  The City of Lakewood has named Mojave Sage as the official city plant.

Rocky Mountain Penstemon (Penstemon strictus) - The tall showy spikes of intense blue-purple flowers last for over a month in late spring. Penstemon strictus is one of the longest lived, most easily grown of the Penstemons.

Noxious Weed: Dame’s Rocket. 
A good alternative is Pink Wild Snapdragon (Penstemon palmeri), a heat tolerant beardtongue, native to NM and AZ. One of the few fragrant Penstemons, it blooms with gigantic spikes of large, light pink flowers in early summer. Must be grown in sandy or gravelly soils, not in tight clay. Best in a dry location.

Noxious Weed: Bouncingbet. Good alternatives include:

Rocky Mountain Bee Plant (Cleome serrulata) – This annual will grow two to five feet tall. Bees and insects enjoy the nectar from the blossoms, and seeds are often consumed by morning doves.

Purple Coneflower (Echinacea purpurea) – Available in a variety of colors, a favorite in many Colorado gardens.

For a full list of Colorado' Noxious Weeds, go to: http://www.colorado.gov/cs/Satellite/Agriculture-Main/CDAG/1174084048733

Tech Helps Dandelions Ooze : Discovery News

The dandelion, that most reviled of "weeds" may have come into its own.  We may be driving our hybrid cars in a few years on dandelion tires!  How's that for green.

Read this:

Tech Helps Dandelions Ooze : Discovery News

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Plant Alert: Giant Hogweed by Mary Small

Recently I was directed to an on-line article in which a popular local author recommended the use of Giant Hogweed (Heracleum mantegazzianum) as an exotic ornamental. While an unusual and attractive plant, it is on the Federal noxious weed list - for very good reasons. If moist skin (say from perspiration) contacts plant sap and the affected area is exposed to sunlight, painful, burning blisters result. Some people develop painless red blotches that turn into purplish or brown scars that can persist for several years. If sap should get in eyes, temporary or permanent blindness can result.




Giant hogweed crowds out native species in various ecosystems including streams/rivers and disturbed areas. It prefers moist soil. Here’s a description of the plant taken from this King County, Washington web site: “A member of the parsley family, its most impressive characteristic is its massive size. It reaches a height of 10 to 15 feet when in flower and has hollow stems, 2 to 4 inches in diameter with dark reddish-purple spots and bristles. Coarse white hairs at the base of the leaf stalk are also purplish, and each purple spot surrounds a blister-based hair. The deeply incised compound leaves grow up to 5 feet in width.



Giant hogweed flowers mid-May through July, with numerous white flowers clustered in an umbrella-shaped head that is up to 2.5 feet in diameter across its flat top. The plant produces flattened, 3/8-inch long, oval dry fruits that have a broadly rounded base, and broad marginal ridges.” It has not yet been found in the Colorado countryside, nor is it in an adjacent state. It is similar in appearance to cow parsnip (Heracleum maximum or H. lanatum), which does grow in Colorado. However, cow parsnip does not have purple blotches. In the author’s Colorado garden, it grows to about 6 feet with a 4 foot spread. Management of giant hogweed requires persistence regardless of the digging, mowing or herbicides used. The seeds are viable for 7 years. Do not purchase seed of this plant or transplants. We do not need this exotic pest in Colorado.

Bindweed Mites by Mary Small

Recently there was a program on NPR that discussed bindweed mites, a biological control agent of field bindweed and some of its relatives. I found some background information for you on the internet that discusses their biology and also about a distribution program that Adams County is doing in July. You may want to refer folks to this information.

http://www.colostate.edu/Dept/CoopExt/Adams/weed/bindweed_mite.html


The main points to keep in mind about the mites is that they don't perform well in irrigated sites (i.e. irrigated lawns) and it takes a few years for them to successfully control the bindweed. According to Tony Koski, CSU Extension Turf Garss Specialist, a product that contains Quinclorac (i.e., Ortho's Weed B Gone Max plus crabgrass control) does a really good job of bindweed control in home lawns. Spot treat only.



Mary

Weedy Things by Late Bloomer

One week in May:
Don't get me wrong. Last month I even loved seeing the weeds because I had been green-starved for too long. But that time is past and I have declared war on the unwanteds. My weedy things are another story. Weedy things are those self-seeding, spreading, creeping, and multiplying wonders that sometimes get carried away. I confess, I often let them take over in places where I need that kind of help.


Grape hyacinths make baby bulbs that magically sprout everywhere. They are not my favorite thing and are harder to remove than bindweed. But the unusual blue floweres are very welcome in early spring.




Lily of the Valley is beautiful with its little white bells lighting up all the shady places. They spread like the dreaded broadleaf grass in my yard.


Mint is very guilty of this too, but easy to control in a whiskey barrel.











Raspberries have woody spreading roots, but are easy to dig up and move or pot up and gift—unlike the horrifying thicket-ing habits of my grandmother's lovely yellow prairie rose nearby.








Dragon's blood sedum is my favorite ground cover. Started twenty years ago from one plant, I have it everywhere and it keeps out weeds as every good ground cover should, and spreads only where welcomed.




The silver dollar plants have heart shaped leaves and bloom profusely right along with the tulips. They are very weedy, but are not competitive, so they don't mind being surrounded with rampant garlic, mint, dandelions and grass. Later in the season they produce lunar-like seed pods for dry bouquets. Sweet Woodruff is delicate of leaf and flower, and spreads where invited.

The loveliest accident in the yard is a pale pink rose that grew and spread from the root ball of an aspen planted years ago. When it jumps the grass stop and invades the lawn it gets treated very badly.

Embarrassing Weed Story by Carol King

Every gardener probably has an embarrassing weed story. An exotic plant pops up and is nurtured and later turns out to be a musk thistle. Or the new house has some gorgeous plant that resembles a sedum and is really myrtle spurge (on list A of the Noxious Weed Act of Colorado). The “morning glory” growing up the rake you left in the garden is not a piece of yard art but instead a neglected tool covered with bind weed!
My most embarrassing weed story to date happened last summer. I always let the sunflowers that pop up from feeding the birds grow, no matter where they are. It adds a sense of randomness to the garden that I like. Several came up in the front garden and started to grow, and grow, and grow. I knew they were going to be giant mammoth sunflowers; the kind that wins prizes and ends up in pictures of largest grown produce; next to the 1,000 pound pumpkin. I envisioned receiving the purple grand champion ribbon and could read the headlines: “Area Woman Grows World’s Largest Sunflower”.
All summer, I watered and fed my plants and was encouraged by the large leaves, the glossy green color and the height, my goodness the height. Toward the end of July, they actually grew taller than the eaves of the house and then flower buds appeared and did not look at all like sunflowers. I looked closely and saw that the leaves on my giant plants did not exactly match the leaves on the other sunflowers in the garden. I had the uneasy feeling that these might not be sunflowers at all.
Sure enough, research proved that my prize plants were Ambrosia trifida; and yes it is a member of the sunflower family (Asteraceae). I say this to redeem myself for feeding, watering, and tending giant ragweed all summer. At least I discovered my mistake before it bloomed. Each plant has the ability to produce about a billion grains of pollen. And because it is the greatest allergen of all pollens and the main cause of hay fever in North American, my three lovingly attended plants would have garnered the headline: “Area Woman Causes Sneezing, Runny Nose, and Itchy Eyes in Major Population Area”. And no purple grand champion ribbon either.

Preparing to Eradicate Giant Ragweed