Scragggily Petunias & Dividing Daylilies

Question:

  • Heat Advisory - WATER- WATER- WATER 
 I’ve cut back my scraggily Petunia plants because they looked awful. They are planted in containers, growing in full sun, and watered daily. So, I'm at a loss as to why the leaves are yellowish. Are they getting too much water, not enough, or is something else going on? 

Answer:

  •  It's not unusual for Petunias to get leggy.
  • To limit the legginess, trim Petunias after every blooming cycle or as necessary. When you do cut them back, reduce the size of the plants by fifty percent. This will force the lateral shoots and keep the plants compact.
  • I don't think the yellow leaves are a watering problem. It is typical to water container plants daily when the temperatures are over eighty degrees. However, the water must drain out the bottom of the containers. It would be best if you emptied the saucers of any water; better yet, remove them altogether.
  • If the lower leaves turned yellow, you could make a case that they were in too much shade. However, it's more to lhe thinking that your problem is a nutrient issue if all the leaves are yellow. When the leaf color begins to fade, I will suspect a nitrogen deficiency. Nitrogen is the element that makes plants green.
  • Seasonal color in containers requires more fertilizer than those in the ground: nutrients, especially nitrogen, leach out of the soil with every watering. It would be best to fertilize regularly; otherwise, the plants get hungry.
  • One way around this is to fertilize with a time-release plant food like Osmocote. A little bit of nutrients is released with every watering, and it is only applied twice during the growing season. Now is an excellent time to trim/prune/cut back summer annuals that are getting leggy. There is plenty of time for them to re-bloom before the season changes. 

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 between the clumps. How long do I need to wait after I apply the weed killer before replanting?  

Answer:

  • There are many organic and nonorganic, nonselective herbicides on the market.  A nonselective herbicide kills grassy and broadleaf undesirable plants. I would ask the nursery professional at your favorite garden center for a recommendation.  Generally speaking, these products work within three to four hours, but they vary with the product. So, I'd wait a day, and you should be okay to replant. 
  • There is another way to deal with this problem. Monterey Grass-Getter will control the grass in the existing clumps without harming the Daylilies. Now you can control the unwanted vegetation before dividing the clumps and eliminating the waiting period.
    • After replanting, it is a safe bet that the unwanted grass will return because of the dormant weed seeds in the clumps. To prevent them from germinating, I'd apply a pre-emergent herbicide such as Monterey Weed Stopper or Preem after replanting the clumps.