We have several holly bushes along our front walkway. One of them is losing leaves and turning pale yellow. Another seems to have a dead spot on the top middle about a foot wide. The others are a little lighter in color except for one that is deep green and is full of foliage. I am concerned about the cause being something that can spread to all of them, but don’t want to be hasty in pulling the worst one out either if it is something that can be fixed. They are pretty mature bushes measuring 3 or 4 feet wide and about 2 feet tall.
We also have found a lot of Japanese beetles and have been given a wide range of advice about how to treat from chemicals to bags, but we aren’t sure which may be best. They seem to be focusing on our Japanese maples, our fire bush, and my hydrangeas.
There is also a very nice thick lawn, and although we would like to train our two dogs to only do their business in the mulched areas this may take some time, and in the mean while we have a lot of yellow dead spots.
The problem with the holly is that it has too much water on the roots. It is possible that, even with the same amount of water given to each bush, the drainage under this particular holly is poor, and the roots are sitting in water too long after rain or irrigation. This problem generally results in yellowing leaves that drop off, particularly at the bottom of the plant and in the inner parts where less light is received. Checking the soil moisture a few inches below the surface should provide a clue, and if it is wet, help it dry out by removing any mulch that may be around this plant. If necessary it is a good idea to add a good dose of compost to the base of the plant. This can be purchased, but it is by far the best if you make it yourself, either from a heap, or if space is limited, a compost tumbler.
Japanese beetles will eat over 300 different plants. Beetle traps (bags) use a floral lure and a pheromone lure to attract beetles to the general vicinity of the bag. If there are plants susceptible to Japanese beetles near the trap, they will actually get more damage due to the attraction of beetles to the area. Place beetle traps at least 75 feet away from plants damaged by beetles. Spray plants that are under attack with an insecticide labeled for Japanese beetles and the plants in question. This will kill the beetles, although they will still have to eat a little of the plant in order to get the insecticide. Also, if you haven’t already done so, use a grub killer in your lawn right away. The beetles are laying eggs in your lawn and you will have damage caused by the grubs this fall if you do not act now to prevent this.
The spots in the lawn from dog urine are caused by an overdose of fertilizer. You may notice that the grass around the dead spots is actually darker green and grows taller, up to the point where the urea in the urine was too much and burned the grass out. The only way to prevent this (besides training) is to flush the area with water to dilute the urine. There should be no problem growing grass in these spots if the fall when temperatures have cooled (September is a good time), but you will have to water the seedlings at least once a day and keep the dogs away so they don’t trample the new grass. Sometimes it is easier to transplant sod from another area of the lawn and seed all in one spot. The sod will need at least as much watering as the seed, but at least the dogs will be able to run in that area.
Thanks to Garden Eaze for help on this article.