Winter isn’t usually thought of as a time to spray your plants. As spring approaches, though, two come to mind – anti desiccant and dormant oil.
When we enjoy enough warm winter days, your evergreens may need an anti desiccant touch-up. When the temperature rises up into the 50s, the sun can melt anti desiccant. It’s a wax like material designed to melt off in the spring. When spring teases us with previews of what’s in store, the temperature rises sufficiently to melt the anti desiccant.
If you applied anti desiccant yourself last fall, just repeat the procedure now. You probably don’t have to apply it as heavily as you did the first application. We have crews out touching up those applications we made. So, if you want us to revisit your plants, just contact our office.
The second application is dormant oil. Although it’s a little early for applying this material, we’re beginning to take requests for this service. Like anti desiccant, there’s a small window of opportunity for dormant oil. So, we’re planning our routes so we can serve as many property owners as possible who want this service.
Dormant oil is a horticultural oil formulated to smother overwintering insects while the trees, shrubs and insects are dormant. The target insects wake up just before the plant leafs out. Target insects include such common pests as aphids, adelgids, mites, lacebugs and mealybugs.
This product is like diluted petroleum jelly that is used on burns and other human wounds. When sprayed on a plant, it covers the plant and the sleeping insects. Since the target insects breathe through their skin, or exoskeleton, the dormant oil coats them and they don’t wake up.
The window of opportunity for applying dormant oil begins when temperatures rise to 40-50ºF and stay there for 24 hour periods and ends just before the plant’s leaves break bud. Spraying dormant oil on leaves can have the same effect as it does on the insects. It clogs the leave’s stoma (pores) and interrupts transpiration.
Like anti desiccant, dormant oil is sold in spray bottles at garden centers. Also like anti desiccant, these are fine for a couple of perennials, small shrubs or dwarf conifers but you can get very tired using this application method on all the plants in your landscape. Also, you can’t reach to tops of tall trees. This is when professional application is preferred. Besides being kinder to your body, it’s also more economical than buying all those bottles at retail.