Fall is such a productive and important season in the garden. It’s the ideal time to plant and an essential time to clean up and clear out. With that in mind, here are a few suggestions on how to be proactive in caring for plants and trees, including the ones you move indoors.
Before moving plants inside
Non-hardy plants thrive in most parts of the country during the warm months but will quickly die if left outside over winter. As fall temperatures drop, the ritual of hauling tender plants inside begins.
Relocated plants make great indoor winter companions but insects that hitchhike on them are usually not as welcome! Before bringing the plants inside, I thoroughly wash them off with a stiff blast of water to eliminate most bug populations (along with two seasons of pollen).
Then look over the plants one more time, especially under the leaves where bugs love to hide. If the water didn’t eliminate the problem, spray insecticidal soap on the leaf surfaces.
This is a non-selective but effective control that dries out most soft-bodied insects such as aphids, white flies, spider mites and trips. I prefer this method because it only kills on contact and has no residual effects once it is dry.
You can make your own solution using one teaspoon of dish soap to one quart of water. However, water quality and soap strength can make a difference. To be safe, insecticidal soaps such as Safer’s® brand that are reliable and consistent are readily available wherever gardening products are sold.
Proactive care of outdoor plants and trees
Even when we clean up and clear out, certain pests and diseases will find their way into your garden. Some of the most destructive pests like the Hemlock Wooly Adelgid, hatch from eggs when temperatures begin to warm in early spring. They’re born hungry and quickly begin their rampage.
Unfortunately, like many destructive pests, by the time their presence is noticed, much of the damage is done. Without a proactive way to deal with the problem, the long-term results can be fatal.
Effective treatment for this and similar pests in the home landscape can be treated with dormant oil. This is highly refined oil that disperses with water. Trees and shrubs are sprayed in late winter or early spring before pests become active. The oil provides a suffocating coat over the offending pests and eggs, eliminating the risk of damage.
However, treatment in this manner must be timed appropriately and trees that become too numerous or large can be a challenge. In the spirit of IPM (Integrated Pest Management), the risk of losing precious trees to a pest whose presence is highly likely surpasses my threshold of tolerance and requires proactivity.
To deal with most pests in the safest manner possible, timing is critical. In the absence of ideal timing, treating plants and trees with systemic insecticides in the fall can effectively control potential infestations in the spring and beyond.
When applied around the root zone, the control is absorbed into the tissue where it can remain viable for up to a year. Fall application is helpful to allow sufficient time for the active ingredient to translocate throughout the trees before infestation.
In the consumer market, the most frequently used active ingredient for this is Imidacloprid. It is commonly found in stores as Bayer Advanced™ Tree and Shrub Insect Control. Because the chemical is in the tissue, not on it, only sucking or chewing insects are affected.
From potted plants to irreplaceable trees, proactive care in the fall is a great way to protect them for years to come.
I have two 70′ Hemlocks with the wooley aphid problem. Since I just bought this place now I see this destructive problem and its spring I had an idea I would like your opinion.
Borax/boron is used to kill ectoskeleton insects which I believe the aphid is. I am thinking to make a borax sugar water solution /one or two gallons for each root system.
1 lb per each gallon?
I don’t know about that solution. My research says horticultural oil is the best thing to use to coat their bodies and that will kill them.
Hello Joe, I read the entire section on pm with comments and will try the milk/water ratio as soon as it quits raining. I am in Nebraska and we went thru a 100-year flood. This year everything is covered with white powdery stuff but when I spray it something jumps off that is white and hairy and small. Is this the woolly aphid? I have been using Orthonex but it is so strong and is killing me along with any bug. I am raising Monarchs and will be working with our State bee keeper to establish hives on our acreage. Got to go GREEN! How can I get rid of these hairy, chewbaccas? Every thing you wrote was so helpful, thank you, Deb
I am growing medicinal plants. every year I have trouble with powdery mildew and whiteflies. I am trying to stay organic. is neem oil considered a dormant oil? is it organic? what would you use on medicinal plants to prevent these issues?
Neem oil is not a dormant oil but it is organic. But you don’t use it to treat whitefly or powdery mildew. I have an article on controlling powdery mildew using milk and water that you should search for on the site. As for whitefly, my choice for organic control would be insecticidal soap. I’ve written about that too so check it out when you do your search. Good luck.