Despite the unseasonably warm weather we've been experiencing in Santa Cruz county this Winter, one should not forget that we're deep into Fall and Winter is just around the corner. Taking a look around the garden, fruit trees, roses and other deciduous ornamentals are beginning to, slowly but surely, lose their leaves and go into their winter state of dormancy. What this means is it's time to think about spraying these plants with a Dormant Spray mixture to ensure their health and prolong their life.
What is a Dormant Spray mixture? It's a combination of a fungicide (Fixed copper or lime-sulfur) and an insecticide (Volck oil, or horticultural grade oil). These ingredients are all listed by CCOF (California Certified Organic Farmers) as approved for use on organic farms. There are some concerns about long term ill-effects of using fixed copper as it builds up in the soil so I would recommend using lime-sulfur on all of your fruit trees, with the exception of on your apricots which can experience serious damage from sulfur.
What's the purpose and function of dormant spraying? When used in conjunction with one another, the copper or lime-sulfur and horticultural oil mixture help control a myriad of potential problems for your deciduous trees and shrubs. The horticultural oil kills overwintering insects, such as scale, mites, aphids and their eggs as well as acting as a "sticker-spreader", or adhesive, that allows the fungicide to better adhere to the plant. The copper or lime-sulfur part of the spray kills overwintering fungal organisms such as Anthracnose, Rust, black spot, brown rot, powdery mildew and the dread Peach Leaf Curl.
When should you spray? Ideally, three applications, spread 30 days apart should be performed to ensure the death of overwintering organisms. This year is tricky since it's still warm and the plants are confused and many still are holding onto their leaves (and, in many cases, fruit) so we may miss the first application which generally should happen in late November. I used to recommend 3 dates to remind people of when to spray: Thanksgiving, the December Holidays, and Super Bowl Sunday. If this warm weather continues to be a trend in the later months of the year, I may have to restructure these dates. But, it is usually safe to think of an application in the later parts of November, December and January. If you can only perform one application, the late January one is the most important because it is imperative you time this before flower and leaf bud break. It is also important to note that one should remove all leaf debris and any wood, generated from pruning, away from the trees and that this debris should not be incorporated into your compost unless you are sure it generates enough heat to kill any organisms that may be living within it.
It is also worth noting that it is important to spray your fruit trees but not always necessary to spray your dormant ornamental trees and shrubs. There's a reason for the old adage "If it ain't broke, don't fix it". If you haven't experience fungal or insect issues with these plants, there's really no need to spray. The less substances you can use to keep your garden in good health, the better.
With spraying comes a few things to be careful about. The dormant spray mixture can be applied with a hose end sprayer or a tank sprayer, depending on the situation and the size of the tree. Be care not to overspray neighboring plants, trees and lawns. This mixture is intended for dormant, deciduous plants and will burn the foliage off and possibly kill any evergreen plants it comes into contact with. Read and follow your products labels and warnings. Do not spray on rainy or windy days. If it rains within 24 hours of spraying, you will need to repeat application. Wear protective clothing, eye protection, gloves (rubber is best) and lung protection. If you can use a respirator, use it. Remember: The term "Organic" does not always equate with the word "Safe". These products can be serious skin, eye and lung irritants and it's important to be mindful of this at all stages of application.
If you have any questions or would like us to perform this service for you, please contact us and we will be happy to assist you.
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