“A Chrysanthemum by any other name would be easier to spell.” — William J. Johnston
The cooler weather feels wonderful. It is sad to know winter is near but fall can be so beautiful in the garden. Annuals are still blooming until frost and mums are starting to bloom. Many of you are planting some potted mums to add more color to the landscape.
The mums you purchase at this time of year are perennials. Unfortunately, they usually will not survive the winter since their root system is not established. The secret to growing mums that survive our winter is to plant them in the spring or early summer. Mums are usually sold as small plants at nurseries in spring but most people ignore them and instead buy the plants that bloom during summer.
If you have hardy mums in your garden now, they probably have grown tall and leggy. To prevent this next year, pinch them back every two weeks until mid-July. This should solve the problem. Give them space to grow and divide them every spring. Fertilizer is necessary for bigger flowers.
If you really love the mums you purchase at this time of year, you can keep them over winter by not removing them from the pots. You can bury the pots until the first frost then bring them indoors. Cut them back and they will then produce new leaves. In spring, plant them outdoors again in the ground. You will get flowers twice in the season. This happens because the hours of light and dark are the same in spring as in the fall. Mums react to this trigger by blooming.
Chrysanthemums and poinsettias are day-length sensitive plants. This is called photoperiodism. They set their flower buds at night so they need more than 12 hours of darkness. Some plants are so sensitive to light that even a short blink of light will prevent them from setting buds. This is why most people cannot get a poinsettia to bloom again. These are called short-day plants. On the other hand, there are plants that need 12 hours of light to bloom properly. One of them is the Easter lily. These are called long-day plants. There are day-neutral plants that just do not care like asters who have a combination of both.
There are also some seeds that are light sensitive. Lettuce and impatiens are an example. They cannot be covered with soil since they need light to germinate. Most weed seeds are in this category. These seeds can be dormant for years but if you till a weed free garden you will turn up most weed seeds and subject them to light.
Many plants are going dormant about now. This also is in response to the amount of dark and light. When you buy seeds or trees, be sure they come from the Midwest since their period of photoperiodism is consistent with Wisconsin. Several things trigger dormancy but the major one is shortening day length. This is important when moving plants from one area to another. For example, a sugar maple grown in the Midwest from the seed of a sugar maple grown in the south will never be able to survive our Midwest winters, even if it is the same variety of maple grown here.