Dandelion Control Should be Done Now

2014-04-26 10.02.21

Photo by Nic Colgrove

Weeds in the lawn will drive us crazy through the whole summer, but don’t forget about them yet. Fall is the best time to treat for broadleaf weeds, even though we don’t notice them as much now because they are done blooming for the year.

Perennial broadleaf weeds including dandelions, creeping Charlie or ground ivy, and clover are best controlled in the fall once the weeds have begun their preparations for winter. In the fall months, these perennial weeds will move sugars that they use for energy from the above ground portions of the plant down into the roots to store them for next spring. If they are sprayed during this phase of their lifecycle, they are more likely to take that herbicide down into the roots and kill the plants rather than just burn the tops off.

The cooler temperatures in the fall are better for turf and ornamental plants due to a reduction in volatilization. In the warm summer days, the herbicides we typically use on broadleaf weeds can turn into a gas and move to non-target plants, causing damage and in some cases even death. With the cooler temperatures, this is not a big concern because the common chemicals we use, such as 2,4-D and Dicamba, do not volatilize at temperatures below 80 degrees. Wind drift is still a concern, so always be sure to apply herbicides on days with little to no wind.

The fall is not the time to worry about or treat for summer annual weeds such as crabgrass. Those plants that are still alive will die with the first frost and the seed will not germinate until next spring when the weather warms back up again. However, you can treat now for winter annual weeds such as henbit, speedwell, and little barley. Once they have germinated this fall you can use a 2,4-D product, which can be achieved with a late October and into early November application for dandelions.

Remember, all of these chemical controls are pesticides and therefore need to be carefully considered and applied according to the label. Any material used to maintain a landscape, including fertilizer, sand, or pesticides, can end up in the storm sewer and lead to pollution of lakes, rivers, and streams. In the same manner, even our grass clippings and leaves can pollute our water supply. There are ways to manage our landscapes while reducing water pollution. The following will help when managing our lawns this fall:

  1. Any fertilizers, pesticides, and grass clippings should be swept back onto the landscape. Using a leaf blower will work as well. The idea is to keep these items on the greenscape rather than on the hardscape that leads easily to the storm sewer. Raking up leaves in the fall will also help reduce the amount of leaf debris that ends up in the water.
  2. Check your sprayers before using to ensure they are properly calibrated and the nozzles are not clogged.
  3. Compacted soils and thin turf do not allow fertilizers and pesticides to infiltrate the soil surface. Aerate and add organic matter to improve the composition of the soil to ensure these products do not run off of hard, compacted soils. Reseed bare areas of the lawn to catch lawn products.
  4. Thatch layers in the lawn can become a natural barrier to prevent infiltration. Aerate the lawn to reduce the thatch layer to allow lawn products to infiltrate their intended areas.

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Yard and Garden: March 31, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for March 31, 2017. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 28, 2017. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Natalia Bjorklund, Nebraska Extension Educator in Dodge County

1. The first question was when can we begin applying crabgrass preventer and fertilizer to our lawns this spring?

A. These are both best applied in late April to early May. Crabgrass will not germinate until the soil temperatures are consistently at 55-60 degrees Fahrenheit.

2. A caller wanted to know if he should mulch his asparagus and if he can use ash wood mulch around his asparagus?

A. Yes, mulch is one of the best ways to manage weeds in an asparagus patch. Ash wood chips would be fine. You do want to avoid Walnut wood chips because walnuts produce juglone which is a chemical produced by the tree to act as a weed control for nearby plants. This helps walnut trees with competition in the wild.

3. This caller has a goldenrod that has grown too large and messy for the area where it is planted. How can it be killed and what Goldenrod would be a better choice for a less messy plant?

A. 2,4-D or simple hand removal should kill the plant. When purchasing a Goldenrod plant in the future, any of the varieties would be better than the straight species. Fireworks is a nice, open goldenrod. Wichita Mountains and Baby Blue would be good choices as well.

4. Is it too early to transplant hostas? When should you cut back warm season grasses?

A. Wait a couple of weeks to transplant the hostas until the soil has warmed up a little more. You can cut back the ornamental grasses anytime now. It is better to get the old growth cut off before growth resumes so you don’t cut off the new growth. For ease of cleanup with the ornamental grasses, wrap string or twine around the plant before cutting off the old materials so it stays together when taking to the compost pile.

5. A caller wanted to know how and when to prune roses?

A. Wait until a little later into April to start pruning them. It depends on the type of rose to know how to prune them. This sounds like a climbing rose which can be pruned back about 1/2 to reduce the size. Wait until they start greening up to know which areas of the canes have died back, the dieback should be removed as well. If the canes are long and lean over mowing areas or other things, they can be tied up to a trellis.

6. This caller wanted to know how to get rid of cockleburs?

A. While talking with the caller, it came up that the plant had very small yellow flowers on it and there were spines over the plant except right at the soil surface. This plant is in fact buffalobur, not cocklebur. These are easily pulled up if you pull where there are no spines. A 2,4-D product could also be used if there was a large amount of them in the lawn.

buffalobur, Howard F Schwartz, Colorado State Univ, Bugwood

Buffalobur plant from Howard F. Schwartz, Colorado State University, Bugwood.org

7. A caller wanted to know if they should water in their crabgrass control?

A. The label will explain to you how a product should be applied for best efficacy. Always read and follow the label instructions to apply correctly. For many of the crabgrass preventers, they would need to be watered in, but again, check the label to be sure.

8. When should asparagus be fertilized?

A. Apply a general fertilizer or a composted manure to the bed after the last harvest or sometime in the fall.

9. This caller has mulberries growing in the windbreak. After they are cut down, what kind of stump treatment should be done to keep them from regrowing?

A. 2,4-D concentrate should be used as a stump treatment. This will take multiple applications and will be more effective if done in the fall. Each time the 2,4-D is reapplied it should be applied into newly drilled holes or to a freshly cut area of the stump.

10. A caller has cedars growing in their landscape. Under the cedars there is bare ground. What can they plant in that area to avoid weeds coming in?

A. The cedars are going to keep that area quite dark and the cedars will take the majority of the water in the soil so mulch would be a good alternative. If plants are desired, use a shade tolerant groundcover such as wintercreeper or vinca vine or perennial plants such as bleeding hearts, hostas, coral bells, jacob’s ladder, and others.

11. This caller has tiny cedar trees coming up throughout the lawn. How can they be controlled?

A. Cut them off at ground level. If a cedar is cut below any lateral growth it will not regrow. Mowing over them wouldn’t be low enough.

3-step pruning cut

Proper pruning cut, University of Missouri Extension

12. When is the best time to prune a maple tree that had a branch break in a storm?

A. As soon as the storm has passed and it is safe to do so, you should remove a branch that broke in the storm. If the damage occurred in a winter storm, let the ice and snow melt off first. Then, hire a certified arborist to come out and make a good pruning cut so that the tree can seal off the wound quickly and fully.

13. A caller has a hibiscus tree that is turning yellow and many of those yellow leaves are falling off the tree. It was moved indoors during the winter months in an area of the house with low sunlight. What is wrong with it and will it survive?

A. Hibiscus plants would need more sunlight than what it has received through the winter. It should be fine once it gets more sunlight. As the days get warmer, you can move it outdoors for more intense sunlight. It should be fine once it gets moved to better growing conditions.

14. This caller has a weeping willow tree that they would like to prune up a little. When can they prune it?

A. The weeping branches shouldn’t be pruned up too much or they could lose their weeping habit. Willows tend to have a heavy sap flow in the spring if they are pruned then, so it would be best to wait until later fall to prune a willow.

15. This caller has grasses that are coming up among the gravel paths around his daylily patch. What can he use to prevent those plants from coming up?

A. Preen is a great way to stop the germination of annual weeds, such as many of our weedy grass species. If they come up before the preen gets put down or if they grow as a perennial weed, you can use a post-emergent herbicide. If it is a grass that is growing out of place among daylilies, you can use Grass-B-Gon or a similar product to kill grasses.

henbit, steve dewey, Utah State Univ, Bugwood

Photo of henbit is from Steve Dewey, Utah State University, Bugwood.org

16. What can be done to manage henbit?

A. At this time of the year, there is nothing very effective at controlling henbit. Henbit is a winter annual plant, meaning that it germinates in the fall and flowers and produces seed in the spring. It dies with the summer heat. As we are now seeing the purple flowers from henbit, there is no need to control what you are seeing. The seed is already present in the lawn for next year and what you would be spraying will die soon. You can hand pull it now and spray with a 2,4-D product late in the fall.

17. This caller has moon flowers that had a lot of hornworms on them last summer. What can be done this year to reduce the number of hornworms?

A. Just because there were hornworms there last year doesn’t necessarily mean you will have a lot this year. Hornworms are sporadic pests. They are easily controlled by hand removal. You can also use sevin or eight or any other general insecticide. Use Bt to protect other pollinators as Bt is only harmful to insects in the order Lepidoptera which includes butterflies and moths.

18. What do you do for bindweed in a vegetable garden?

A. If you haven’t planted yet this spring, you can roundup the plants before you prepare the soil for the summer vegetables. The plants will probably still be a problem later in the year as this is a difficult pest to control. When it comes back in the summer, you can carefully use roundup through the growing season. You can paint the glyphosate product onto the leaves of the bindweed avoiding spraying the desired plants.

Henbit?!

Henbit from canva

It’s spring, finally! I know our winter wasn’t terrible this year, but I always look forward to spring. That is such an exciting time of the year, all of our plants are greening up and the early blooming trees, shrubs, and bulbs are beginning to show us their beauty for the year. However, not everything about spring is fun and games. This is the time of the year I always get calls about that dreaded purple flowering weed in our lawns and gardens.

Henbit is the purple blooming weed that shows its ugly face very early in the spring. This is the weed that will cover crop fields early in the spring with large expanses of purple blossoms. This weed is also quite prevalent in our lawns and gardens.

henbit, steve dewey, Utah State Univ, Bugwood

Henbit is a member of the mint family, which means that it has square stems. It has leaves that are rounded with a scalloped edge and they are arranged oppositely along the stem. It has a small purple flower with darker colored purple spots on the lower petals of the flowers. Henbit is often confused with creeping Charlie or ground ivy, which is a perennial weed from the same family with purple colored flowers as well. The differences between the two are that creeping Charlie is a perennial so it blooms later in the year than henbit and creeping Charlie has flowers that are more blue and henbit flowers are more purple.

Henbit is a winter annual. This means that henbit only lives for one growing season, but it’s development is different from something like crabgrass which is a summer annual. A winter annual is a plant that germinates in the fall and grows a bit before basically becoming dormant for the winter months. Very early in the spring, henbit will start to grow again, produce flowers which produce seed for the growth to come next year and then it dies. A winter annual dies as soon as the weather starts to warm up in the late spring whereas a summer annual germinates in the spring and goes through it’s lifecycle through the summer months, dying with our fall frosts.

The problem with henbit is that by the time we see it, or rather see the beautiful purple flowers, it is too late to treat it this year. As I said, henbit dies when the weather warms up, so why spray it with a chemical when it is going to die in a few weeks anyway. The fact that it is noticed when it is blooming shows us that it is already producing seed for next year, so killing the existing plants does nothing for the future generation of this plant. However, pulling the plant would be a fine management practice in the spring months.

Henbit is a plant that tends to grow in the areas where grass typically dies out. Areas around sidewalks and driveways or areas where people tend to cut the corner around sidewalks are locations where the turf gets worn down and the henbit excels. Henbit is also often found along the foundation of a house or in a garden area with exposed soils. If we can do things to keep your grass growing in these locations or use other plants or mulch to cover the bare soil, the henbit will struggle. Using a pre-emergent herbicide for broadleaf weeds in the fall will also help reduce the seed germination. Finally, using any broadleaf post-emergent herbicide later in the fall after the henbit has germinated, such as 2,4-D, will kill henbit as well.

Henbit in the lawn

Henbit flower from canva

This time of the year is always fun. It is starting to warm up and we can begin to emerge from our winter hibernation indoors. However, with the movement outdoors come the calls to my office. People venture outdoors and begin to notice plants growing that were not intentionally planted. One of the most common nuisance plants that seems to plant itself in your beautiful lawn and is noticed early in the spring is Henbit.

Henbit is a plant in the mint family and therefore it has square stems. It grows to a height of 16 inches and has dark green leaves that are scalloped along the edges and arranged oppositely along the stem. The leaves are clasping below the flower cluster. It has a purple colored, tubular flower. This is a plant that spreads by seed but can quickly invade turf areas and invade into a flower or vegetable garden. Henbit is the plant that is often seen in masses of purple in fields very early in the spring.

Henbit in field from Purdue

Cornfields full of purple henbit (Purdue Agriculture photo/John Obermeyer)

Henbit is a winter annual plant, which means that it germinates in the fall or winter. It then grows for a period of time in the early winter, goes dormant in the very cold periods and resumes growth early in the spring to flower and produce seed. After flowering, it will die, because it has set seed for new plants for next fall and spring.

People typically only notice henbit in their lawns in the spring when it is flowering. However, the best time for management is in the fall when it is first germinating. If you use chemicals to control henbit in a lawn, it is best to do prior to flowering and seed production. In the spring, when most people see henbit, there is no need for chemical controls because the plant has already set seed for next year’s crop and the plants seen are on their way to death anyway.

Management can be successful without chemicals. Henbit is a plant that does well in the areas where our turf does not. It grows well in compacted soils, typically along the edges of sidewalks and driveways where it can easily outcompete our turf for the space. It also grows well where there is good soil moisture and shade. Because of this, it is easily managed by encouraging a dense, vigorous turf or to change the landscape by utilizing other plants besides turf or applying mulch in areas where turf struggles and henbit grows well. Henbit can also be hand-pulled for quick removal, this is the preferred method of control in the spring. If chemicals are necessary and desired for management of Henbit, they should be applied in the fall. Products that contain 2,4-D have the best control for Henbit.

henbit, steve dewey, Utah State Univ, Bugwood

Photo by: Steve Dewey, Utah State University, Bugwood.com

Henbit is often confused with Creeping Charlie, or Ground Ivy, because they are in the same family of plants and they both have similar flowers. Henbit is a winter annual, while Creeping Charlie is a perennial, so henbit will flower well before Creeping Charlie does in the spring. Also, Creeping Charlie tends to have more blue flowers while Henbit has more purple-lavender flowers. Henbit has clasping leaves below the flower cluster, while Creeping Charlie does not. Be sure you know which plant you are dealing with to achieve the best control.

Yard and Garden: April 17, 2015

Yard and Garden Green Logo

This is the Q&A for the Yard and Garden show for April 17, 2015. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2015. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Dr. Paul Read, Professor of Horticulture, Viticulture Specialist

1. A Caller wanted to know if this was a good time to transplant rhubarb?

A: Now would be a fine time to transplant rhubarb. If you wanted to harvest from it yet this year, it would be best to wait until the fall to transplant it. Rhubarb should not be harvested from within the first 1-2 years after transplanting to allow the plant to build a good root system before harvesting begins. Make sure that rhubarb is planted in a well-drained location to avoid getting crown rot, a disease that will eventually kill the plant.

2. An email listener wanted identification and control strategies on her plant with purple flowers that is blooming now.

A: This is henbit, a winter annual that is flowering to complete its lifecycle. Because henbit is basically done growing for its lifecycle, it is best to leave it alone and let it die naturally in the next few weeks. The seeds are already in the soil for next year. Henbit is best controlled with a 2,4-D product in the fall. Mark the areas where henbit is found in your lawn this year and spray those areas in the fall. Management also can be achieved by overseeding turf into those areas where henbit is found or planting something else to compete with the henbit.

3. This caller wanted to know how to control clover

A: The best time to control clover would be in the fall with a couple of applications of a 2,4-D product. Applications of this product now can be useful, but will not eliminate the problem altogether. Be sure that when you apply 2,4-D to your landscape to not allow it to drift to any other broadleaf plant, including our trees, shrubs, and perennials. Also, only spray when the temperatures are below 80 degrees Fahrenheit.

4. A gentleman has a lawn that has been neglected for a while that he is struggling to keep turf alive in a full-shade location with poor soil. What can he do to get the turf to live there? Also, in another area of full sun, would dwarf fescue be a good turfgrass choice?

A: Because it is poor soil that had subsoil put on top of the existing soil, it would be best to aerate and add organic matter to try to improve the soil conditions. Full shade is difficult to grow turf in, so it would be best to choose a full shade perennial or groundcover or somehow prune the trees to improve the sunlight for the turf. Dwarf fescue is not a good choice because the root systems are not as deep as the turf-type tall fescues or Kentucky bluegrass.

5. What would be the fruit tree spray schedules for cherry and apple trees?

A: Orchard fruit tree sprays can be applied to both of these types of trees on a 10-14 day interval, while avoiding the blooming period to avoid damage to the pollinators. There are guides to spray schedules from many Universities including one for homeowners from Missouri Extension

6. A caller wanted to know what are some good varieties for pear trees in Nebraska? Does he need multiple species for pollination? How does he mulch these trees?

A: Pear trees are not self-pollinated so you will need to plant 2 different varieties to get fruit. Some good choices for Nebraska would include Luscious, Harrow Delight, Harvest Queen, and Seckel. A mulch ring is necessary to help the tree survive, it should be only 2-3 inches deep.

7. This caller used crabgrass preventer with fertilizer in it a couple of weeks ago and wants to know when he should use his weed and feed? Also, what type of care would he need for shrub roses he just planted this spring?

A: It would be best to just use a 2,4-D product anytime now and wait until the end of May to do another application of straight fertilizer to get through the summer, since he already applied fertilizer with his crabgrass control. The best thing for the roses would be to ensure that they are kept well-watered but not overwatered.

8. A gentleman has Philodendrons and Crotons as houseplants that he has moved outside for the summer. Now the leaves on the Philodendrons are curling up, why is that? Also, what kind of care should be given to the Croton, is misting a good practice for them?

A: These plants are tropical plants that we can grow indoors in our homes. The nights are still too cool for those, which is why the Philodendrons may be having leaf rolling issues. If the weather is predicted to get to the low 40’s to 30’s for the overnight hours, it would be best to bring these plants indoors. The Crotons should be watered properly from the base of the plant to ensure survival. Misting plants leaves the leaves wet which can lead to diseases.

Houseplant

Philodendron picture by Soni Cochran, UNL Extension in Lancaster County

9. What can be done to control ants found in the kitchen?

A: Terro ant baits work the best with the odorous house ant. Also, seal up all cracks and crevices in the foundation and around doors and windows. Clean up plant debris outside the home near where ants are found inside the home to reduce locations where ants may be hiding outdoors.

10. A lady has blackberries that are overgrown. How can she clean them up?

A: Cut out the old stems that are existing and continue to do this at the end of every growing season.

11. This caller has a 30 year-old pear tree that has never produced fruit. She has one pear in her landscape. Why would it not produce fruit?

A: Pears are not self-pollinated. Plant another variety and it should begin to produce fruit.

12. When is the best time to prune a snowball bush?

A: This is a spring blooming shrub, so it is best to prune it immediately after it has finished blooming for the year.

13. This caller wanted to know how to control Dandelions in her yard?

A: 2,4-D products can be used now but will have the best efficacy in the fall. If applied now, ensure that the wind is not blowing and the temperatures are at or below 80 degrees Fahrenheit for the day of application and the 2 days following.

Photo by Nic Colgrove

Photo by Nic Colgrove

14. This caller has started tomatoes and peppers from seed indoors and they are now becoming tall and spindly. What would cause that and when can they be placed outdoors?

A: They will need more light to avoid becoming tall and spindly. Also, be sure to buy clean and sterile soils for seedling production to avoid problems with Damping Off, a disease common to seedlings. Summer crops can be planted outdoors in the beginning of May, typically Mother’s Day is a good date to plant summer vegetable gardens.