Late Fall Lawncare

The fall is a great time to improve our lawns. We have now passed the correct timing for overseeding lawns, but there are other improvements we can still make. Controlling perennial broadleaf weeds and winter annual weeds can be done in October and fertilizers may be applied if necessary.

Broadleaf weeds

perennial lawn weed collage
Perennial Broadleaf Weeds

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, 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 to be more effective than if done in the spring. Spray these weeds with a 2,4-D product 2 or 3 times from late September through the end of October. Wait to spray after temperatures consistently drop to below 80 degrees so the herbicide doesn’t volatilize in hot, humid weather.

Weedy grasses

2018-04-20 12.52.00
Henbit in bloom in the spring

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 and speedwell. Once they have germinated this fall you can use a 2,4-D product, which can be applied as a late October application both for the winter annual weeds and for perennial broadleaf weeds.

Using pesticides correctly

Remember, when using pesticides always be careful and apply pesticides 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 plant material rather than on the hardscape that leads easily to the storm sewer.
  2. Raking up leaves in the fall will also help reduce the amount of leaf debris that ends up in water.
  3. Check your sprayers before using to ensure they are properly calibrated and the nozzles are not clogged.
  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.

Fertilizer

As for fertilizer applications, the fall fertilization is the most important fertilizer application for a lawn. However, fall fertilization recommendations have changed over the past couple of years. For a lawn, a Labor Day to mid-September application of slow release fertilizer is still recommended. Apply a granule with 50% slow release nitrogen or less. If additional nitrogen fertilizer is required later in the fall, use a product with a quick release nitrogen in mid-October. We used to recommend Halloween or later for the second fertilizer application and we thought two applications were necessary. New research is showing us that a second application of nitrogen fertilizer may not even be necessary, but if it is, we should move the timing up to more like Columbus Day rather than the typical Halloween time frame. This information is from Bill Kreuser, Assistant Professor and Turfgrass Extension Specialist from the University of Nebraska-Lincoln.

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Yard and Garden: April 26, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for April 26, 2019. 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 August 2, 2019. 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: Roch Gaussoin, Extension Specialist for UNL Agronomy and Turf

1. The first caller of the show recently applied a Weed-B-Gon product that contained crabgrass control. Now he wants to fertilize, but it is a fertilizer and crabgrass control together. Will it be harmful to put the crabgrass control on twice this spring?

A. That should be fine and you won’t see any injury from applying the crabgrass control twice this spring. You won’t need to apply any additional pesticides for the lawn this year. Next year, it would be better to do a little more planning ahead so you don’t apply the chemical twice so close together. This is just additional pesticides in the environment that are not necessary, so be careful with that in the future.

2. A caller is bringing in topsoil on a new build site. He needs to overseed, but is it getting too late to do that yet this spring?

A. Seeding the lawn will have the best results if done in the fall, but spring can get a good start on a new lawn. The weather will be the problem to lawns seeded too late this year. With the weather as it has been this year, there is likely still a 2-3 week window for overseeding the lawn with fairly good success. It might be a good idea to overseed now and then do another overseeding in the fall to thicken it up. Also, for weed control, it would help to use mesotrione (tenacity) at seeding. There is a starter fertilizer that contains the tenacity to help with start-up of the turf and to keep the weeds down while establishment occurs. It would just help to get some type of cover crop or turf down to reduce the amount of bare soil that weeds can grow into.

3. This caller has henbit. Would it be controlled well with the Tenacity? If so, should he use a stronger dose of the Tenacity because he has tried it with limited success?

A. It is Never a good practice to use pesticides at a higher rate than what is listed on the label. A lot of research went into finding the correct rate for best control of a pest. Henbit is hard to control this time of year, it is best controlled in the fall. It will die as soon as the heat of the summer comes on because it is a winter annual and doesn’t live well in hot weather. Treat in the later fall, October, with a 2,4-D product for best control.

That caller also has a peach tree that just flowered for the first time. It has two 2-inch long cracks on the tree trunk, each on opposite sides. What can be done with this?

A. Unfortunately this tree is not going to live long. There is nothing to do to fix the tree once cracks like this happen. This large of an opening is very damaging to the tree and will not allow the tree to live long. If it is out in the open where it won’t damage anything if it falls, leave it until it dies.

4. A caller has been trying to get a native grass prairie started for a few years now with limited success. He has a mix with Blue Grama, buffalograss, and little bluestem. What can he do to get it to grow better?

A. Don’t give up yet. Be sure to control the weeds with herbicides, 2,4-D won’t harm the grasses but will manage the weeds. After some photos, it shows that there is still some grass in there, but it is very early for these warm-season grasses. Keep mowing to keep the seed heads down for the weeds.

5. Can potatoes still be planted yet this spring?

A. Yes, get the potatoes in soon, and they should be fine yet this year.

What do you do for Pampas grass with a dead center?

A. Dig it up and divide it and replant it. This can still be done this spring.

She has a crabapple that has dead branches in it, can those be cut off now or should they be removed in the fruit tree pruning window of February-March?

A. Remove dead branches anytime of the year that they appear.

6. A caller wants to know when to spray for bagworms?

A. It is weather dependent. Starting in late May, check weekly for the small bags to begin to show up on the trees. When the small bags show up and until they are up to 1/2 inch in length you can spray.

He also wondered when and how to fertilize trees?

A. It really isn’t necessary to fertilize trees in Nebraska. They can get the nutrients they need from the soil naturally.

tree irrigationHow do you water trees that were recently planted?

A. water them one time per week with a slow trickle from the hose for about 20 minutes each time they are watered.

When is the best time to prune cedar trees to shape them?

A. Most anytime would be fine with a cedar tree, but the best time is in the late winter to early spring.

7. This caller has Austrian pines that are turning brown on the tips of the branches with short needles. What is causing this and how can it be controlled?

A. This sounds like tip blight. It can be treated now with a copper fungicide. A second application should be made 7-14 days after the first application.

8. What is the best thing to mulch asparagus with?

A. Grass clippings, straw, hay, or wood chip mulch can all be used to mulch asparagus. It would be best to hand pull weeds and then use preen that is labeled for use in asparagus before applying the mulch. If there is a problem with brome grass, use roundup carefully around the asparagus first as well. To carefully get the glyphosate on the brome and not on the asparagus either paint it on with a foam paint brush or use the “glove of death” which is when you wear a chemical-resistant glove and then put a cloth glove over that. Then, dip a few fingers of the gloved hand into Glyphosate and rub those fingers along the stem and leaves of the bindweed to kill it.

9. A caller has been trying to start seedlings of spruce and fir trees for a few years with limited success. He thinks it may be due to root rot because when he pulls them up the roots look rotten. How can he get the trees to grow?

A. After discussion, it seems that he doesn’t overwater the trees and may in fact not be watering them enough. He also said that he can get the trees to grow in another, more neglected, location. It was suggested that he do a soil test to see what is going on with the soil in this desired location. It might be that there is a hard pan underneath these trees that is impeding water movement through the soil causing the roots to rot.

10. This caller has been trying to get grass started and is having difficulties. He has used an aerator, seeder, lawn roller, and then waters the seed well and it is not coming in very good.

A. It seems his practices are good, so he may try a soil sample to see what the nutrient and pH levels are in his soil.

11. The last caller of the day wanted to know what the difference is between a Sycamore and a London Plane tree?

A. These trees are 2 different species of very similar trees.

 

Yard and Garden: April 27, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for April 27, 2018. 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 August 3, 2018. 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: Dick Campbell, Owner of Campbell’s Nursery in Lincoln

1.The first caller of the show wants to plant hydrangea’s on the south side of a porch. Will they grow well in that location?

A. Most hydrangeas like part shade and wouldn’t grow as well in a location of south sun. However, ‘Limelight’ and ‘Little Lime’ would be good selections for full sun. The ‘Little Lime’ hydrangea will only grow up to 3 feet tall while ‘Limelight’ will grow up to 6-8 feet tall.

2. A walk-in listener has a 12 year old boxwood that is turning whitish-brown throughout most of the plant. What, if anything, can be done to save the plant?

A. This could be boxwood blight or winter desiccation. The fact that the boxwoods started to turn brown in the summer makes it less likely that it is winter desiccation. Also, the plant is brown and dead throughout the majority of the center of the plant, where winter desiccation typically only shows up on the top and outer sides where wind directly hits the plant. Either way, too much of the shrub has become dead branches so it should be removed. Boxwoods can be replanted into the area where the blight was a problem previously with no harm to the new plants.

3. A caller has Dwarf Alberta Spruce trees that have brown spots on them. Last summer he sprayed the plants with a copper fungicide, but should something else be done to them?

A. Dwarf Alberta spruce is prone to problems with spider mites in the summer months. If it is spider mites, when they start becoming active again, they can be killed with a strong spray of water. The bigger problem is that this is a very slow growing tree and it may never fill in again where the dead areas have appeared in the trees.

4. This caller has pecan trees that the top has died back on them over the winter. Can he prune it out and maintain the trees?

A. Give the trees time to leaf out this summer to know for sure where the dieback is found through the tree. With the cooler spring this year, many of our plants are slow to come out of their dormancy. Wait until the tree is fully out of dormancy before pruning it. After it has leafed out fully, cut the dead areas out, but cut back to a bud at the top of the tree so that you can use that bud to reestablish a new leader.

5. A caller has underground irrigation and planted a new lawn via seed and some via sod last fall. What type of watering schedule should he be on now?

A. Because this lawn was established last fall, you would not need to keep up the same schedule as last fall, the roots should be established now. Wait to start up the irrigation after spring rains begin. 1 inch of water per week would be the recommendation now, that is what established lawns require, so it would be the same for this lawn. Most often, we give our lawns 1 inch of water per week through 3 irrigation cycles of 1/3 inch each time. Make sure you check your irrigation rates when you first turn your system on for the year.

6. This caller has a 25-30 foot tall red oak in his yard. Every year for the past 2-3 years, the leaves come out cupped and small and stay that way through the entire growing season. What is wrong with his tree? He has other oaks in his yard that don’t look like this.

A. The cupping leaves sounds similar to herbicide drift. Typically, though, the trees will grow more leaves later in the season that are not cupped. If this was herbicide damage, it is likely that all the oaks in the yard would have this problem, but it still could be herbicide damage. It could also be from a small mite or other insect that is sucking the juices out of the leaves as they emerge. It would be best to bring a sample to the show or to Nicole to take to the lab for further testing. If it is herbicide damage, multiple years with damage to a tree can start to stress and kill a tree.

2018-04-20 12.52.00
Henbit blooming

7. A caller has a zoysiagrass lawn that is full of henbit for the first time this year. Is there anything to do for that now?

A. Henbit is blooming for the year now, which means it is already setting seed for more henbit to grow there next year. Henbit is a winter annual that germinates in the fall, goes dormant over the winter, then comes up in the spring and flowers and produces seed before it dies with the summer warmth. Because it is getting so late in the year and the seed is already there, there is no reason to treat for henbit now. It will die soon, once the temperatures warm up. next fall, treat with a 2,4-D product in October or November to kill it as it first germinates in the fall.

8. How do you control Creeping Charlie in the lawn?

A. Creeping Charlie is best controlled in the fall months with a 2,4-D product or a product containing Triclopyr. It is best to do 2 applications in the fall, one in the middle of September and another at the end of October. The caller was going to overseed, so it was advised to overseed this spring and then treat the Creeping Charlie in the fall for best control. It will take multiple years of treatments to fully reduce or eradicate Creeping Charlie, but spraying in the fall will start knocking it back.

9. This caller has Sod that was installed last November and now some cracks have shown up between the sections of the turf. What can be done to fix that?

A. Add some soil to those areas of bare ground and then reseed those areas. Cover the new seed with peat moss while it establishes to keep it moist.

10. A caller wants to know how to plant strawberries and what varieties are good choices?

A. Sarah Browning, Lancaster County Extension, has written a good article on Planting a Strawberry Bed

11. The last caller of the day wanted to know if they should till their garden before planting and when to prune her hydrangea shrub?

A. If the soil is loose and has a good level of nutrients, you wouldn’t have to till it first. It might be a good idea to till it first to loosen it up and to add nutrients back into the soil for better production.

As for the hydrangea, this is a late summer blooming hydrangea, so it can be pruned now and still produce flower blooms for August or September this year. It can be pruned back to the ground if it is overgrown. If it is not too overgrown, the largest canes can just be cut out of the plant, leaving the more productive, smaller canes in the plant to grow.

What to do in the Spring?

Spring Things Blog Post

Spring is here. That is wonderful for the weather and the desired plants and flowers, but it also means the insects and weeds are coming back. If you know what you are dealing with, management is achievable.  

Henbit

Henbit is one of those not so desirable weeds that shows up in our lawns in the spring. We don’t really notice it until it begins to bloom and at that point, it is too late for control. Henbit is the early spring weed that blooms purple along the edges of our sidewalks and driveways.

henbit, steve dewey, Utah State Univ, Bugwood
Photo of Henbit from Steve Dewey, Utah State University, Bugwood.org

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 and seed for the next year then it will die when the temperatures warm up. This is different from a summer annual which germinates in the spring and goes through its lifecycle through the summer months and dies with our fall frosts.

The problem with henbit is that by the time we see it, or rather see the purple flowers, it is too late to treat for the year. Once the flowers begin to show up, it is already producing seed for next year, so killing blooming henbit is unnecessary because it will die naturally and the chemicals won’t reduce production for next year. However, pulling the plant would be a fine management practice after blooming has begun. It can be sprayed with a 2,4-D product very early in the spring once it has greened up but before it blooms. If you know where it is you can spray it before it blooms. Otherwise, wait until this fall to spray those areas with a pre-emergent herbicide before it germinates in the fall.

Lawncare

This is the time of the year when we want to start seeing color in our lawns. We begin to think we need to fertilize, overseed, and use crabgrass control. Don’t get ahead of the weather with these things. It is still fairly early for overseeding, it can be done in April, but anytime by the end of April to the early part of May is still fine for overseeding. Overseeding too early could cause the seed to germinate in warmer weather. If that warm weather is followed by freezing temperatures, it could damage the newly emerged grass. Fertilization should not be applied until mid to late April when temperatures warm up more consistently.

Crabgrass preventer should not be applied too early in the year either or it will break down before the crabgrass begins to emerge. Crabgrass preventer should be applied when the soils are consistently at 55-60 degrees Fahrenheit. A split application, applying more 6-8 weeks after the first application will ensure crabgrass control through the season.

Asparagus

green-asparagus-pixabayAsparagus is a great vegetable that many people enjoy growing and eating. Now is the time to clean up your asparagus beds if you haven’t done so already. It is a good practice to allow asparagus fronds to stand through the winter to help trap snow during the winter months, providing moisture for the crown of the plant as the snow melts.

If you are planting a new asparagus bed, dig a trench 6-8 inches deep and plant the crowns in that, only covering with a couple of inches of soil. As the plants grow up through the soil, continue to add a couple of inches of soil at a time until the soil in the trench is level with the surrounding soil. Wait for 3 years before you begin harvesting to allow the roots to get fully established.

Salt is not a recommended weed control for asparagus. Asparagus is a salt tolerant plant, but it doesn’t thrive in salty soil environments. Also, the salt in the soil can begin to break down the surrounding soil, leaving you with bad soil for the asparagus and other plants growing nearby. For weed control, it is best to use mulch throughout the season.

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.

ProtectingWaterQualityinLandscapes_Page_1

ProtectingWaterQualityinLandscapes_Page_2

 

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.