Rodd's Seeds of Wisdom Horticultural tips and tricks from Rodd Moesel

The trees have been showcasing a spectacular and ever changing chorus of fall colors the last few weeks as we make the annual march of time towards winter. Frankly the fall colors have been much more colorful than expected after the kind of drought we have endured this summer. The yellow colors have been especially bright and impressive this year with poplars, pecans and walnuts among those dressed in bright yellow right now. The maples were impressive in red and bronze tones but are almost done. The ornamental pears are the trees closing out the fall foliage show in reds and bronzes. Soon the yellows, reds and bronzes will all be gone and we will be left with lots of leaves, rich in nutrients, on the ground and the brown tannin filled leaves on the oaks and the few other trees that cling to their leaves into winter.

This fall color is like a big message board encouraging all of us to plant more trees and shrubs. This is a great time to plant container grown or balled and burlapped field grown trees. Add new trees and shrubs to your yard or take advantage of this fall planting season to replace trees or shrubs lost in the recent ice storms, hard freeze of last winter or the recent summer drought. Visit with your nurseryman to select the right tree for your location. You can select for size, summer color, fruit, fall color, bark, speed of growth, soil type or many other factors.

This is also the planting time for pansies and spring flowering bulbs. The pansies will provide a great show of color and hope all through the winter. They will eventually “wear out” as the heat intensifies late next spring. The spring bulb crops should be selected, purchased and planted now. We won’t see them at all through the winter as they hide under ground. During the winter they will be growing roots and the new leaves and their spring flowers will be getting positioned to spring from the ground at the start of next growing season as the days get longer and the temperatures warm up.

The crocus and the grape hyacinth are usually the first to raise their flowers from the ground as if to announce that spring is getting close. They will be followed by the narcissus or daffodils as they trumpet the actual arrival of spring with their yellow, orange or white flowers waving in the wind. The daffodils are followed by the sweet scent of hyacinths and the majestic floral displays of the tulips. It is hard to believe that so much beauty and color can come so quickly from those bulbs you plant this fall, but it does. You are not able to enjoy the spring flowering bulbs next spring unless you think ahead and plant them now. There are also many varieties of lesser known bulbs that you may want to try as well. Many of the bulbs, like most varieties of hyacinths and tulips need to be replanted each year as most won’t come back in future years and if they do, their flowers are not as impressive in those future years. The daffodils are the exception, and a great choice for Oklahoma, as they will often naturalize and come back in impressive fashion year after year.

Enjoy the chorus of tree colors this fall, the uplifting charm of pansies this winter and plant spring flowering bulbs for a symphony of early spring color.

This is a great time to select and plant your pansies, spring flowering bulbs and new trees and shrubs. “Fall is for Planting” was a major promotion of the American nursery industry for many years back in the days of my youth. They haven’t promoted that phrase for a couple of decades but it still applies. We have had such significant tree and shrub damage from the drought this summer that you may want to replace trees or shrubs you know are dead or add new trees and shrubs to your landscape. As long as you water them periodically this winter they will begin to grow roots and will start to adapt to their new environment. Fall planted trees and shrubs get a head start on spring plantings and are usually better prepared to handle their first hot summer.

Fall color is great garden art and leads to many questions. Temperature, soil moisture, sunlight and day length all influence the intensity and quality of the fall tree color. Night length is the biggest factor in this amazing process. Plants use the chlorophyll, which appears as green in the leaves to manufacture carbohydrates which are stored each growing season in the tree branches, buds and roots to support the next year’s growth. As the days get shorter and the nights longer the cells at the base of the leaf where it meets the stem or branch divide rapidly but do not expand. This makes an abscission layer of corky cells that begin to block carbohydrates going from the leaf to the branch and new minerals from the roots going to the leaf.

Fall color occurs at the same time each year since it is based on day length regardless of whether we are warm or cold. During the growing season chlorophyll is constantly being replaced as the sun breaks it down. As the flow of minerals from the roots is stopped, the leaves cannot make new chlorophyll and this process is slowed down and then stops. As the chlorophyll disappears we begin to see the other colors that have been in the leaves all the time but were covered up by the green chlorophyll including the yellow pigments of xanthophylls and the orange pigments which are carotenoids.

The red and purple pigments are anthocyanins and are manufactured each fall from the sugars that are trapped in the leaf as the process of abscission progresses. As the abscission cells become more dry and corky the leaf/stem connection cells are weakened and the leaves will drop from the tree. Some trees will hang onto their old leaves all winter but the other pigments like chlorophyll will fade out in the sunlight or when the leaf cells freeze and die. The only pigments left in the end will be the brown of the tannins.

Please spend some time outside to enjoy the beautiful and ever changing symphony of fall colors and consider doing your part of “Fall is for Planting” to add more trees and shrubs to your yard.