We call this season the "fall" because all around us right now (if you live near leaf-dropping trees in a temporal zone), leaves are turning yellow and looking a little dry and crusty. So when a stiff breeze comes along, those leaves seem to "fall" off, thus justifying the name "fall."
Sounds reasonable, no? But the truth is much more interesting.
According to Peter Raven, president of the Missouri Botanical Garden and a renowned botanist, the wind doesn't gently pull leaves off trees. Trees are more proactive than that. They throw their leaves off. Instead of calling this season "The Fall," if trees could talk they'd call this the "Get Off Me" season.
Around this time of year in the Northern Hemisphere, as the days grow shorter and colder, those changes trigger a hormone in leaf-dropping trees that sends a chemical message to every leaf that says, in essence, "Time to go! Let's part company!"
Once the message is received, says Raven, little cells appear at the place where the leaf stem meets the branch. They are called "abscission" cells. They have the same root as the word scissors, meaning they are designed, like scissors, to make a cut.
And within a few days or weeks, every leaf on these deciduous trees develops a thin bumpy line of cells that push the leaf, bit by bit, away from the stem. You can't see this without a microscope, but if you looked through one, you'd see those scissors cells lined right up.
That's where the tree gives each leaf a push, leaving it increasingly dangling. "So with that very slender connection, they're sort of ready to be kicked off," says Raven, and then a breeze comes along and finishes the job.
So the truth is, the wind isn't making the leaves fall. It's the tree.
The tree is deeply programmed by eons of evolution to insist that the leaves drop away. Why? Why not let the leaves stick around? Why drop?
Raven explains that leaves are basically the kitchen staff of a tree. During the spring, summer and early fall they make the food that helps the tree grow and thrive and reproduce. When the days get short and cold, food production slows down, giving the tree an option: It can keep the kitchen staff or it can let it go.
If trees kept their leaves permanently they wouldn't have to grow new ones, but leaves are not the brightest of bulbs (sorry!). Every so often, when the winter weather has a break and the days turn warm, Raven says leaves will start photosynthesizing. "They get some water up and they start operating and making food and then it freezes again."
When the cold snap's back on, the leaves will be caught with water in their veins, freeze and die. So instead of a food staff that's resting, the tree is stuck with a food staff that's dead. And when spring comes, the permanent help will be no help. The tree will die.
That's why every fall, deciduous trees in many parts of North America get rid of their leaves and grow new ones in the spring. It's safer that way. So for leaves, falling in the fall isn't optional. The trees are shoving them off.
All the news this week is about Hurricane Florence. At this point in WNC, they are mainly expecting high winds and some flooding. After a big rain the biggest obstacle is knowing what to do to help your lawn as it begins the process of drying. One thing that will definitely speed that process along is making sure that you’ve turned off any sprinkler or irrigation systems that you have. It is easy to forget about these systems, especially if they are automatic, but adding moisture to the ground that is already sopping wet, is not a bright idea.
As your ground begins to dry, you can add fertilizer back to the lawn to replenish any lost nutrients. Adding fertilizer will also help encourage strong root growth, which help to protect your lawn from being completely ruined in a big rain.
If trees went down in your yard, it is a good idea to remove the debris from the lawn, if you are no longer under water. Leaving this debris in place will hinder drying and you can risk bacteria or mold formation. We also suggest that, apart from removing debris, you stay off of your lawn until it’s had the chance to recover. Treading on wet grass can encourage impaction, and you’re more likely to accidentally rip up roots of your grass and plants since the ground is soggy.
In terms of mowing after a big rain, we encourage you to wait a few days. When we experience rain for days or weeks on end, it can also take weeks for the ground to completely dry out. In our case, since it was just a day of hard rain, it shouldn't take weeks, but you do have to be careful. Don’t mow for a few days to make sure that the ground is drying successfully. Mowing wet grass can cause impaction, which will damage your lawn. You also risk damaging your equipment, and if you are using a riding lawn mower it is especially dangerous in our hilly landscape to attempt to mow when your lawn is still muddy.
5 Curb Appeal Tips for Fall
Clean Up the Yard: Keep falling leaves at bay with frequent raking and patch up any brown spots in the grass.
Plant Fall Flowers: As your summer plants start to fade, replace them with vibrant mums or other colorful flowers.
Clean Up the Exterior: Fall is a good time to pressure wash the exterior and clean the windows.
Clear Out All Gutters: Be sure to clear your gutters and downspouts of leaves and other debris, which will protect your home from water damage.
Add Outdoor Lighting: Use decorative lights to illuminate walkways, and install flood lights or lanterns to brighten up entrance areas.
Nothing is more frustrating than spending your free time trying to cultivate a healthy garden, only to have it overrun with underground pests. In this article we discuss what to do about moles.
Poisons are usually the first method that a homeowner thinks of, but is not necessarily the best choice. Poisoned gummy worms or pellets with bromethalin may be inserted in an active tunnel, but they may pose a hazard to humans and pets and may possibly enter the wildlife food chain. If poison baits are left in place, they have the potential of being washed into water sources. When using any type of poison or chemical, carefully read and follow the label instructions.
The most effective control for moles is to cut off the food supply. Using a grub treatment for a lawn is a common practice. Systemic grub treatments that contain imidacloprid as an active ingredient can be applied to the lawn area in May. These are available in ready-to-spray, hose-end sprayers or granular formulations. Granular products are easier to apply, but be sure to irrigate with at least ½ inch of water immediately after application. Because these products are systemic within the turfgrass, they will last the entire growing season. Granular grub killers that contain trichlorfon or carbaryl are contact insecticides that should be applied in early July and are spread over the lawn and watered in well. At this time, the grubs are small and close to the surface, so the contact insecticide will be very effective in eradicating the young grubs. This will last for about two weeks. Application in the late summer or fall is not as effective, as the older grubs will go deeper in the soil and are harder to kill. Neither of these methods are completely successful, as the moles will switch to other prey, such as earthworms and other insects.
As a more environmentally friendly but temporary solution to a mole infestation, consider an application of castor oil to the lawn. It is available as a spray or in a granular form and will repel moles and voles for about two weeks.