Question:
My Daylilies will need to be divided this fall. Once I dig up the Daylily clumps, I'd like to use a weed killer to eliminate the tall, wild grass growing in between the clumps. How long do I need to wait after I apply the weed killer before replanting?Answer:
- The answer will vary depending on which herbicide you use.
- You should use a non-selective herbicide that will control both the grassy and broadleaf weeds. Many organic herbicides are available, so you will not have to use Round-Up or any other herbicide containing Glyphosate. The wait time is short, a couple of hours or a day. So you'll be able to complete this project in a weekend.
- Keep in mind, you’re only controlling the actively growing weeds. There is a good chance that there are many dormant weed seeds in the ground. To prevent these weeds, I'd apply a pre-emergent herbicide. Pre-emergent herbicides control the dormant seeds before they germinate. Monterey Weed Stopper and Preen are two that are widely available.
- Another option is to control the grassy weed before dividing the clumps with Ortho Grass-B-Gon. Grass-B-Gon is a selective herbicide for grass weeds only. Before making a purchase, I'd consult with the nursery professional at your favorite garden center. If you make a mistake, it's not reversible.
Question:
On either side of our front walkway, we have junipers planted that are twenty years old. One side has always been a problem, and now the other side is starting to turn brown. We want to remove them and start over. Before we replant, is there something we should treat the soil to prevent this from reoccurring?Answer:
- The problem you're describing is root rot. Soil erosion and excess summer moisture are the primary causes of juniper root rot.
- The typical symptom is that a section or branch of a plant will turn brown for no apparent reason while the rest of the plant is not affected. The dieback progressively getting worst over time. With those plants on a slope, the plants in the middle and towards the bottom suffer first. After that, the decline is random without any particular pattern. With new plantings under two years old, the entire plant dies.
- It's not necessary to treat the soil before replanting. Instead, root rot is avoided by changing your cultural practices. When replanting, place the root balls of the new plant half an inch above the grade.
- Soil is sloped along the exposed sides to insulate the root ball in hot weather. This will force the soil around and away from the crown of the plants. Once established, junipers are drought tolerant, requiring little moisture during the summer months when we have average winter rainfall.
- Depending on the temperature and exposure, once a month or every three weeks is sufficient. Drip irrigation will minimize erosion when the rainy season concludes.
- And finally, avoid planting junipers next to a lawn as the problem will repeat itself.