Welcome to our Gardening questions and answers page. If you have any questions about your garden, or any plants in your garden, please feel free to submit them at the bottom of this page. We're pretty busy, so give us a day or two to respond.

Question?

        I am constantly having to pull grassy weeds around my Iris. I have recently decided that hand    weeding is against my religion. Are there any herbicides that will control grassy weeds, but not harm my Iris's.

Answer:    

        For this particular problem you will need a herbicide that will kill the grass, but not the Iris. Trade names for herbicide that will accomplish this task are:

• Poast

• Grass-B-Gon

• Over-The-Top Weed and Grass Killer

        Be patient, it may take some time for the grass to die. Also, hot and dry weather  may magnify the effectiveness of any chemical you use in your garden. So be careful not to over do it. Before using any chemical of any kind in your garden, Please read the label, and always follow the directions.

Question? 

       When is the best time of year to seed my lawn? I have heard that you can seed in the Fall or in the Spring. Is one better than the other? See also,   7 Steps to overseeding your lawn

Answer: 

        The best time of the year to seed your lawn is in the Fall. The second best time of the year to seed your lawn is in the Spring. Essentially, Fall is a better time to seed for one big reason. That big reason is Crabgrass. During the Spring you will want to put a preemergent on your lawn to prevent the germination of all unwanted annual grasses (Crabgrass). Seeding your lawn in the Spring gives Crabgrass a window of opportunity to germinate right along side with the grass that you have just seeded. If you seed in the Fall, the threat of Crabgrass invading your lawn does not exist. Generally, any Crabgrass that hasn't germinated by August probably isn't going to germinate at all (for that growing season). Therefore, Fall is the best time of the year to seed your lawn.

Question?

        I've heard that Walnut trees will kill some plants when they are planted too close to Walnut trees.  Why is that?

Answer: 

        The leaves, nuts and roots of Walnut trees produce a toxic chemical called juglone. Juglone, when taken up by other plants that may be planted close to Walnut trees, such as, apples, tomatoes, asparagus, potatoes, lilac and mums, may experience "Walnut Wilt". (not to be confused with "The Bar Bell Bloat") Plants susceptible to Walnut wilt will, of course, show signs of wilting and possibly dying. Another symptom, is that the inner stem tissue of the wilting plant will turn brown.

         It all depends on how close the plants are planted to the walnut tree in question. Not all Walnuts will kill these plants, the ones that do are: Persian walnut, pecan, black walnut and butternut. If you want to plant one of these walnut trees, you will want to plant these well away from your garden. If you already have a garden close to one of these walnut trees you may want to remove the walnut tree all together. If you do remove a walnut tree for this reason, keep in mind that the roots of the tree will continue to grow for at least one more year, so it is possible that you will continue to see walnut wilt in your garden, for at least, two years after the tree has been removed.

Question?

        What is a preemergent herbicide? When and how should it be used?

Answer:

First and foremost: Always read the directions and any warning labels that are on any herbicides that you might be applying to your lawn. Always.

Herbicides can be put into two categories. Preemergent and postemergent. 

        A preemergent herbicide is applied to a lawn or flower bed before the target weed (the weed you are trying to kill) has germinated. It is usually applied in granular form.

        A postemergent herbicide is applied to a lawn or flower bed after the target weed has germinated. It is usually applied in a liquid form (but not always).

        In the Kansas City area, preemergent herbicides are predominantly used to control crabgrass (annual seed grasses) in lawns. A preemergent would be applied to a lawn in the Spring, before the crabgrass germinates (early March to April). Preemergents are not meant to kill crabgrass after it has germinated. I have been told that Dimension, a popular preemergent can kill crabgrass if it has recently germinated, however, this is not something that should be counted on. This means, that for best results, you should time your application prior to the germination of the crabgrass in your area. Crabgrass germinates when the soil temperature reaches approximately 60 degrees. The timing of your application should be before this. A good indicator is to watch for when the Forsythia blooms. When you see this, go ahead and put your preemergent on your lawn. It may not sound all that scientific, but it does work.
        After you apply a preemergent to your lawn be sure to water it in. Most preemergents do not become effective (chemically activated) unless they are watered in after they have been applied to a lawn. 
        Also, do not disturb the soil surface in any way unless you have to. Disturbing the area of application will probably nullify the effectiveness of the chemical.

Question?

GW's jet        

Answer:

Question?

        I have weeds growing around a Dutchman's Pipe. Do you have any ideas on what I could do? Please, I need help!

                                                                            Mathew

Answer:

        Mathew, not having grown Dutchman's Pipe or Aristolochia, I can't recommend any weed preventing chemical solutions for this problem (however, preemergents will probably work, but definitely not any broadleaf weed killers), however, I will tell you what I do for my Morning Glories or any other plants I have this same problem with (ornamental grasses). Remove all of the unwanted weeds from around the base of the plant, then put weed mat down around the plant(s) that you are trying to keep the weeds away from. If you do this, buy a good quality weed mat so that it will last several years.  Also, be aware, that if you put a weed mat down, it could hinder the spreading of any perennials in the same proximity of your flower bed. Weed mat is a great way to keep the weeds out of your flower beds. It is a physical barrier that lets the water get to your plants, while not letting the weeds grow in your bed, and, best of all, it does this without the use of chemicals. After installing the weed mat then place a mulch (wood, rock, whatever you prefer (I always prefer wood mulch because my lawn mower has a tendency to throw the rock through windows)) on top of the mat. Here's a picture to give you some idea of how to install your weed mat. One last note, make sure that you secure the weed mat down with garden staples, and don't be stingy with the staples. Use a staple at least one every two feet or so(especially along seams in the middle of the bed), this should keep the mulched flower bed looking good for a long time.
                       

Question?

        Before the snow and frigid cold this year, I mulched my perennial bed.  Now that the snow is gone, the mulch looks much thinner.  Should I mulch again, or is it too late to do any good?

                                                                            Carol  

Answer:

        Carol, I highly recommend that you remulch your bed. One of the mistakes that homeowners make, that I have noticed over the years, is that they don't mulch their beds with the proper amount of mulch. (I'm talking about wood mulch here) When you mulch a bed, you should spread the mulch so that it is at least 2 inches deep.  I would recommend that if you are mulching a bed for the first time you need to put at least 3 to 4 inches of mulch on a new bed. After that, top dress (another 1 to2 inches) the bed as needed. "As needed", is up to the homeowner, however, to keep the bed looking in top form, I would suggest that "as needed" is twice a year. Using enough mulch is the best thing you can do to protect your perennials from the cold weather and desiccation during the winter months. The combination of cold weather and desiccation will probably terminate a lot of plants in our gardens this year. The cold weather we can't do anything about, however, proper mulching (and watering during the winter months) will minimize the negative effects of desiccation.
        Do not over mulch your beds. I've only seen this twice in 15 years so it isn't a very common problem. If you get to the point where your layer of mulch is 5 inches thick you may create an environment where there is no oxygen underneath the layer of mulch. Over time, due to compaction and rot, the wood chips create oxygen poor zone underneath the mulch. This means that the roots of your plants aren't getting any oxygen, and therefore, will either die or do very poorly (depending on the plants and the amount of oxygen available). It takes a long time and a lot of mulching to produce this condition (also a lot of neglect). At this point, you need to remove the old mulch, find a way to aerate the soil without disturbing your plants or just redo the bed entirely.

Other suggestions when mulching flower beds:

        Find a way to contain the mulch in your bed. Use either black plastic landscape edging (be careful when your mowing), metal edging (be very careful when your mowing) or just do what I do and edge by digging a small trench. This will delineate your bed from your lawn area and improve the look of your bed considerably. This will also minimize the amount of mulch that spills out onto your sidewalk or lawn area during a hard rain.

        If you use a dyed mulch your bed will look in top form for a much longer period of time. This will reduce the number of times a year that you have to top dress a bed. When using the usual wood chips (hardwood or whatever) you will notice that after about 3 months the sun washes the color out of the mulch, and the bed doesn't look nearly as good as when it was freshly installed. Dyed mulches are more expensive, but if you only have to top dress them once a year, as opposed to twice a year as with regular hardwood mulches, then they are cheaper and keep your bed looking good throughout the growing season.

Please submit any gardening questions you might have in the form below. We will do our best to answer all questions as soon as possible, thank you.

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