Columbus Day weekend mark’s the middle of meteorological fall. It’s the point where the days really do constantly start turning colder and the nights become more and more likely to bring a frost. This means the foliage is coming on strong and it’s time to begin moving houseplants back inside. There is a trick to getting your plants through the winter if they have been outside all summer.
Returning Houseplants To The House
First, I treat all my houseplants with horticultural oil and a systemic insecticide. Since I am not eating the plants and there aren’t any beneficial insects inside my house, I am ok using these types of chemicals.
I wait about a week or two after treatment before the plants come inside. This ensures the insects are dead. If you must bring the plants in immediately do a spot check. If you see aphids, scale or spider mites cover the entire plant in a clear plastic bag. The unhealthy plants can quickly affect the healthy ones which were not brought outside this summer.
If you have plants you want to keep alive, but dormant, move them inside as late as possible. For example, I leave out my rosemary through Thanksgiving and then move it into the garage. I also move other more frost tolerant plants like cactus, ornamental pomegranates and oleander after several hard freezes. These plants are kept in colder areas like an unheated porch, but don’t experience the deep cold of being outside. This is a great way to keep many plants alive all winter. Just remember they will use very little water in this suspended state. Over watering and root rot is the biggest mistake people make to plants in the winter.
The leaves are rapidly changing from green to other shades of red, orange, yellow and brown. The leaf color comes from natural pigments inside the leaf tissue. Two of these pigments, chlorophyll and carotenoid are always present.
carotenoid (yellow, orange, and brown)
During the growing season the chlorophyll masks the carotenoid, that’s why summer leaves are green, not yellow or orange. The red shades are produced in fall by the anthocyanins are produced only in autumn, and only under certain conditions. Many of you likely love the red colors the most and not all trees can make anthocyanin. The shorter days and cooler air both combine to signal for the leaves to make this red pigment.
You likely learned in about the third grade Chlorophyll is the most important of the three. Chlorophyll is an integral part of photosynthesis. These molecules absorb the sun’s light and release energy. Without the chlorophyll in leaves, trees wouldn’t be able to use the sunlight to produce food.
Carotenoids create bright yellows and oranges in familiar fruits and vegetables. Sweet potatoes, corn, carrots, even bananas are colored by carotenoid. Anthocyanins add the color red to plants, including cranberries, red apples, cherries, strawberries this is why these “turn red” when ripe.
This weekend you’ll notice plenty of color, but also a lot of green. The leaves are nearly 7 to 10 days behind what is typical including last year. The two maps below show what color was like in 2014 and what is occurring now. You can find more of my gardening and weather information on Twitter @growingwisdom.