When most of the country continues to recover from the pandemic, the Japanese Beetles have put the virus behind them and are out in force. We are seeing more of them this year than we have the past couple of years. These hungry pests are hard to figure out. They ravage some roses such as Touch of Class and Beverly while not bothering other varieties such as St. Patrick. They have a real passion for the fragrant blooms, especially those that are light colored. They will also attack many of your other flowering plants. There is really no good answer as to how to eliminate this pest. Cindy likes to take a stroll through our garden once or twice a day and she simply knocks the beetles off into a bucket of soapy water. If this does not appeal to you, another option is to spray an insecticide for them, such as Bayer Rose and Flower insecticide. However, be careful as you do not want to kill everything in the garden including the good bugs that eat the bad bugs. I can almost guarantee that if you spray Sevin throughout your garden, you will get a big dose of spider mites. One alternative is to simply spray the buds and blooms where the beetles do most of their damage. If you do decide to apply an insecticide, try doing so later in the day to avoid killing all of your honey bees.
Speaking of honey bees, we are seeing more and more of them in our garden. This is probably due to the fact that we do not spray for insects until we see them. We are also careful about when we spray, doing so when the bees are not out in the garden.
So far this summer, we have had periods of rain followed by days without any. As usual, some areas of the tri-state have gotten more rain than others. That is why we highly recommend you purchase a simple rain gauge to help you keep track of the rainfall in your garden. In the heat of summer, it is very important that your roses get between 2 and 3 inches of water per week. This sounds like a lot, but roses use lots of water when it is hot. Rather than applying a full three inches of water at one time, you’ll get more for your money by applying an inch of water three times a week. Be sure and water early enough in the day to allow your foliage to dry before nightfall, as wet foliage at night provides the perfect environment for an outbreak of blackspot. When the weather is really hot, nothing feels better than a nice cool shower. The same is true for roses. They enjoy a nice cool shower in the heat of the day. We also like use a strong spray to “wash” our foliage, making sure to hit the undersides of the foliage, which will help keep spider mites under control. We do this about once or twice a month and it has helped us to virtually eliminate spider mites in our garden.
The organic fertilizer that you applied (or should have applied) in the spring is about gone, so now is the time to apply another round of organics. Organic materials provide minerals bound in complex compounds that need to be broken down by soil microorganisms. Since the process is limited by microorganism activity, organic materials provide nutrients slowly. This slow rate of application will also not burn the fine feeder hair roots that are so important to the health of your roses. Organic materials include pasteurized chicken litter (one of our favorites), cottonseed meal, alfalfa meal, composted manure, fish meal, kelp meal, etc. There are also some excellent pre-packaged balanced organic fertilizers on the market such as Mills Mix, Rosetone and Plantone. Regardless of what organic material you use, be sure to lightly incorporate it into the soil and water well.
For a little summertime pick-me-up, incorporate some fish emulsion or liquid kelp with your favorite liquid fertilizer of choice. We actually prefer using the fish emulsion plus liquid seaweed. This will help your roses handle the stress from the hot July sun.
Be sure to continue your spray program to prevent any fungal infection. Hot humid weather is the perfect breeding ground for the dreaded blackspot. If, however, you maintain a regular spray program aimed at preventing blackspot, you shouldn’t have too much of a problem with the disease. That being said, during periods of daily rainfall it can be difficult to maintain your weekly spray program. So far, we have had a relatively small amount of blackspot in our garden. Once you get blackspot, it can be really tough to get under control. Do your best to keep blackspot out of your garden! However, if you do get an outbreak, we suggest you try using Manzate, Dithane or Mancozeb twice a week until you see it clear up. During periods of heavy rain, we add Dithane to our weekly mix. Always remember to read the label of any pesticide you use and never apply chemicals at a higher than recommended dosage as it will probably result in burnt foliage.
The July heat can also be tough on the rosarian, so be sure and protect yourself from the sun with a good sunscreen and proper clothing. When you’re out in the garden providing your roses with lots of water, don’t forget to provide yourself with some too. Remember that visitors are always welcome at our monthly meetings. We have a great program scheduled for July 22. If you’re interested in learning how to grow these fascinating plants, why not check us out.