Greetings everyone. My name is Nate Jackson and I am the horticulture and propagation manager here at Midwest Groundcovers. What the heck is that you ask? Basically I am in charge of plant health, soil, water, fertility, and propagating new plants (reproduction through cuttings). Its quite a handful but I can't think of a more enjoyable position to be in. While Kevin is out 'tying the knot' he asked me to fill in and share some disease issues we see in the nursery and that you might be experiencing at home. I think it is a very pertinent topic for the type of year we have been having here in northern IL and I hope it helps you understand the nature of various plant diseases a little better.
As I'm sure most of you who live in the Chicagoland area are aware, we have had an abundance of rain this year. While rain is important to keep gardens thriving, it also promotes one of plants biggest enemies - foliar disease. When talking about foliar problems, there are two main types of issues that you run into; one is fungus and the other is bacteria. It is important to know what you are dealing with because the cure for each is different (for concrete diagnosis, you should take your sample to your local arboretum or contact your local university extension office). However, the way they grow and develop is very similar. To make it very simple - fungus or bacteria are all around us; in the air, soil, leaves, etc. Like any living organism, they need nutrients to thrive and unfortunate for plant lovers, many of those nutrients are found in the foliage of our favorite trees or shrubs. The majority of the pathogens need moisture to develop as well; hence the problem with continuous rains. The spore or pathogen lands on the leaf, begins feeding and is helped along with a little water and before you know it, leaf spot is present. Once the problem has developed, the rain adds to the outbreak by literally splashing spores or bacteria around, spreading them to other leaves making a small problem a very big one rather quickly. Below is a picture of a very common fungal pathogen that I'm sure anyone with roses in their garden has seen- rose black spot.
1) Start with a good plant - buying disease free plants and cultivars that are disease resistant is the number one thing you can do to keep a healthy garden. Simply googling disease free roses, for example, will give you a plethora of options that are resistant (not immune) to certain foliar diseases. There are few things that are completely resistant to pathogens, but resistant varieties offer a good starting point.
2) Begin spraying early - if you decide it is in your best interest to use chemicals to control disease, make sure you start early. Once disease develops, it's difficult to completely kill. Start spraying as soon as buds break and spray on a 14-21 day schedule on things that you have seen major problems with in past years. Thoroughly covering all your foliage is important and following all labeled directions will ensure personal and plant safety. Look for general fungicides in your local garden center or box store and read the label carefully to see what it treats - only spray things that it is labeled for.
3) Try not to overhead water - as I mentioned earlier, one of the biggest proponents to disease development is free flowing water. You can add to the problem by watering over your infected foliage, spreading spores and disease. Watering from the base of your plants and keeping foliage as dry as possible will help curtail any disease development and spread.
4) Do some cleaning in the Fall - The vast majority of foliar diseases can easily overwinter in the soil, on canes, and on dead, fallen leaves. This is where they start in the spring and is the main reason you see the same problem from year to year. Making sure to clean up all leaf debris around diseased plants is the number one most effective thing you can do to ensure disease does not pop back up next year. As soon as the plant defoliates, clean as much material as you can to ensure a good start for the next year.
With all of this rain we have had, it is very difficult to keep disease in check. However, if you follow those simple guidelines, it will help with future development and hopefully will stem the spread as well. There are thousands and thousands of different types of pathogens that effect plants, but the vast majority will only cause aesthetic damage. If you can stay away from chemical applications and just prevent the problem by buying a quality product and keeping things clean, it will not only make less work for you, but will help out mother nature as well. I hope this helps one or two of you out there and I'll be back next week to talk about some common creepy crawlers that may be causing you problems. Happy gardening!
WELCOME TO THE MIDWEST GROUNDCOVERS DISPLAY & PLANT TRIAL GARDENS!
There's so much that changes in the MG landscape throughout the year...we thought a plant trial and garden blog was the best way to start sharing "what's new" and "what's happening with all those new varieties" with you! Visit often for updates on how trial plants are performing in the gardens and to see photos throughout the season as we grow and change!