Evolutionary biologist Mercedes Burns of the University of Maryland, Baltimore County, should draw a large crowd when she discusses her research on...
Harvesters or daddy-long legs mating. (Photo courtesy of Mercedes Burns Lab)
Harvestman collected in Japan. (Photo by Mercedes Burns)
Mercedes Burns on collecting trip in Japan.
Crabgrass season is off to an early start this year. If the seeds are present in the soil, the only requirement in our area is three days in a row of temperatures 50 -55 degrees for those seeds to germinate. While we are enjoying a little warmth and the bloom of daffodils, forsythia and nut trees, this weed, really an annual, is invading our lawns, vegetable patches, and garden landscapes.
Two types exist: smooth and large. Smooth is a summer annual, spread by seeds and culm nodes on top of bare soil. You can mow it down to ¼ inch and it will still set seed waiting to surprise you given the right conditions. This is the type most commonly found in lawns.
Large crabgrass also spreads by seed and by nodes lying on top of bare soil that root. It's called “large” because it can grow to 2 feet if not mowed. According to UC IPM, one large crabgrass plant can produce upwards of 150,000 seeds, and the seeds from both large and small crabgrass can live at least 3 years in the soil. In other words, take care of the problem weed now, or you will be taking care of it all summer.
The best strategy is to have good strong turfgrass to prevent crabgrass from taking root in the first place. Fertilize your lawn when it is growing. Over-seed your lawn as needed. Don't over-water your lawn. Deep, infrequent irrigation is better than short, daily watering. Mulch garden beds. Soil solarization can be used as a long-term strategy. Many gardeners use pre-emergents, but they have to be applied before the seeds germinate (which they likely already have) and the pre-emergents can prevent the fresh lawn seed from germinating. It takes about 4-5 months for the pre-emergents to break down.
One option that has been touted is corn gluten meal, CGM for short. It is a by-product of corn milling and it has about 9-10% nitrogen, so it's a fertilizer, too. But research studies from California, Washington State University and Iowa State have shown that CGM is not effective outside of greenhouse conditions for crabgrass control and extermination. Weather conditions have to be perfect to allow the CGM to dry up the emerging weeds, and CGM is expensive. The recommended amount is 20-40 pounds per 1000 square feet and then it needs to be applied twice a year. And if you are trying to grow organically, you would need to research if the CGM is milled from genetically modified corn.
Finally, post-emergent products are available, but the crabgrass has to be small (1-3 leaf stage), otherwise, the product can damage the good turf around it. More information about specific pre-emergents and post-emergents for homeowners and professional landscapers can be found on the UC Pest Notes #7456 and “The Myth of Weed-Killing Gluten: ‘Cornmeal gluten is an effective organic herbicide'”, by Dr. Linda Chalker-Scott.
Large Crabgrass flower
A unique UC Davis symposium on "Saving a Bug's Life: Legal Solutions to Combat Insect Biodiversity Decline and the Sixth Mass Extinction" will...
The Western bumble bee, Bombus occidentalis, is a candidate to be listed under the Endangered Species Act. (Photo by Kathy Keatley Garvey)
If diversity is the spark of life, then the Bohart Museum of Entomology is fueling that spark into a full flame. The Bohart Museum, home of nearly...
Butterflies from Belize are part of the global collection at the Bohart Museum of Entomology. They are (far right) Blue Morpho, Morpho helenor montezuma; (top left), a leaf mimic, Fountainea eurypyle confusa; and blue hairstreak, Pseudolycaena damao, according to entomologist Jeff Smith, who curates the Lepidoptera section. (Photo by Kathy Keatley Garvey)
This is part of the beetle collection at the Bohart Museum of Entomology. (Photo by Kathy Keatley Garvey)
An Australian stick insect (walking stick) at the Bohart Museum of Entomology. (Photo by Kathy Keatley Garvey)
My husband and I just returned from celebrating our 25th anniversary in Maui. We had honeymooned there and celebrated my parents' 50th anniversary there, so Maui has always been special to us. In addition to the whale, sea turtle and surfer watching, and snorkeling I have always loved spending time with the tropical plants here. The grounds of the resort/condo complex we stayed at were just lovely. I was impressed with the combination of plants and bromeliads. The burgundy and green color combination was striking without a single flower in sight.
Venturing out to the parking area I saw a lovely tree. I don't know what kind of tree this is but it had pinnately compound leaves. What impressed me most about this tree was the root system that was visible above the ground. It was really quite massive and took up every bit of space it had been given. I would love to know what the below-ground root system looked like. This tree was making the most of what it had and was thriving.
Close to the first tree, I saw another smaller tree. Its gnarled trunk and branches had been adorned with air plants and orchids. I've got to admit that I felt more than a twinge of envy at this point. I certainly wouldn't be able to do that in Fairfield.
Another day we went up to the town of Makawao which is considered upcountry as it is situated on the slopes of the dormant volcano Haleakala. This area has ranching and farming. The first thing I noticed was hibiscus in the parking lot that was the size of a small tree. The town was charming with many boutiques and restaurants. Outside one of the stores was a bucket filled with bouquets of Protea for the grand price of $10.00. Guess this is one of the benefits of living close to a Protea farm.
Next time I would like to find out if there are tours offered at this farm. I know there are tours at a nearby lavender farm and at the Surfing Goat Dairy. That's the thing about Maui, no matter how many times you go, you find more that you want to see next time.
photos by Karen Metz
tree roots maui