Horticulture Hotline 09/06/23
Bill Lamson-Scribner
After last week’s Horticulture Hotline, I had some people ask me about weak crutch angles and about tree structure in general. If you hold your hand, like you are holding a can or a bottled beverage, your thumb and your pointer finger would make a “U.” A “U” is how you want your tree limbs to come together. If you hold up a “Peace Sign,” your pointer finger and your middle finger make a “V.” You do not want your limbs to come together as a “V.”
When you were a kid, you might have learned that you could count the rings of a tree to determine the tree’s age. Limb’s get bigger and bigger each year (hopefully). As they get bigger year after year, if they are connected by a “V,” the limbs begin to push against each other and become susceptible to splitting. If you were a super thin and tall (6’6”, 165 pound) 16-year-old boy and you bent your arm at the elbow, your forearm and bicep would make a tight “V” at your elbow. Then one day you decide you want to be the biggest Sumo Wrestler ever in history, so you eat and work out with lots of curls. You become 6’8” and 650 pounds. Now when you bend your forearm to your bicep by the miracle of the joint in your elbow, the arm stays attached even though they have grown much bigger. A tree does not have an elbow or a joint, so splitting become an issue.
Right now, there are a lot of national advertisements directed towards fall fertilization. These national ads are directed towards cool season grasses, like fescue. Most of these products have a fairly high first number - Nitrogen (18-24), a fairly high middle number - Phosphorous (18-24), and the last number – Potassium, between (8-14). In the Lowcountry where we have warm season grasses, our needs are totally different.
Our warm season grasses are getting ready to go dormant for the winter. Cool season grow best right now and in the early spring while our warm season grasses are dormant. The fall fertilizer for this area would have very little nitrogen, if any, and a high micro-nutrient package, especially iron. Rarely on a soil test do I see a recommendation for Phosphorous at all because of the high levels of Phosphorous that are naturally occurring in our soils (Ashley Phosphate Road!). Potassium is also good to add at this time of year in the Lowcountry.
There are several products on the market that are good fall fertilizers for our warm season grasses. At Possum’s, our three most popular fall fertilizers are; 00-00-25, Possum’s Minors and SeaHume. Depending on your soil tests or what you have applied this season, one of these products will meet your needs. These products contain proprietary ingredients that will benefit your lawn at this time. Cotton Burr Compost is another organic product that can be used alone or in combination with one of the above products. These products will help your yard this fall and, in the spring, when the grass is coming out of dormancy. It is always best to go to sleep (dormancy in this case) with some food in the belly (roots).
Iron, magnesium, and manganese are important for your lawn in the fall because they are part of what makes up chlorophyll. Iron is the center of the chlorophyll molecule. The chlorophyll is what makes grass green. By adding iron now, you get a lot of green in the leaf blade. The green in the leaf blade is what catches the sun’s rays and performs photosynthesis. The photosynthesis is what produces sugars (carbohydrates). These carbohydrates are stored as roots and other woody structures. A high amount of sugar in the plant will also help the plant avoid winter kill (acts like anti-freeze). It will also keep it green in the fall longer and it will green up earlier in the spring.
If you think of the old TV’s that had dots on the screen that made up the picture, the iron will make more chlorophyll (dots on your TV screen). Just as the more dots give you a better picture, the chlorophyll will give you a better-looking greener lawn and collect more sunlight for the grass plant.
