Wildflowers Gone Wrong & Raising The Soil Level

Question:

 Last fall, I purchased and scattered several packages of wildflower seeds. When I sowed them, I wasn't paying attention, so the seeds blew all over the place. I now have them growing in all the wrong areas. How do I get rid of the problem in a ground cover or at least prevent new ones from growing?   They’re mostly broadleaf types of wildflowers.

Answer:

  • In ground covers, there are no selective herbicides to control the actively growing broadleaf weeds.
  • The safest and unfortunately the most labor intensive is to remove them manually. For grassy types of weeds, you could use Grass Getter or Grass-B-Gon.
    • If some of the unwanted wildflowers are growing in bare spots, you spot treat these areas with Roundup or similar product. You protect the desirable plants with a cardboard plant shield that isolates the desirable plants from the undesirables and then spot treat with the herbicide.
  • Wildflower mixes are made up of annual and perennial varieties, so a portion of the problem is going to die out on its own.
    • To prevent them from returning, apply Monterey Weed Impede in the fall. Impede is a pre-emergent herbicide that inhibits the weed seeds from germinating. Pre-emergent herbicides are applied right over the top of rooted plants without damaging them. They’re watered into the soil to set up a chemical barrier that kills the seeds.
    • If the area weren’t under irrigation, I'd withhold applying the herbicide until just before the first major rainstorm of the season. There is no problem in using these products in November. The chemical barrier remains effective all winter long as long as you don’t cultivate the area. It’s too late to apply Monterey Weed Impede now as the seeds have already spouted.
  •  While there isn’t a lot you can do today, I think you can eliminate the problem over time with a little patience. 

Question:

We would like to raise the soil level about one foot around four very old and lovely-blooming Wisterias. Our first choice would be to bury each plant. Is this possible? Our second option is to dig the plants up and replant them. The last thought is to install plant wells around each plant. What would you suggest?

Answer:

  • Of the three options, the least desirable is to bury the plants by raising the soil level. Actually, this is not advisable at all as it's a sure proof way to kill them.
  • The Wisterias could be transplanted to a new location, but given their age, it may not be feasible. I think the most practical solution is to build permanent plant wells around each plant. They should extend from the trunk to beyond the drip line.
  • This is where the majority of the roots are located. You can use a variety of materials such as railroad ties, concrete blocks or moss rocks to hold back the soil.