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Imagine being an LCO (Lawn Care Operator) and doing your best to give a customer (let’s call him Geoffrey) a great lawn. He pays for a seven-step program, aerates and over seeds every few years. He irrigates, too, but Geoffrey’s lawn is stuck in the mediocre category. How could this be? Because he’s a lawn scalper!
“What’s a lawn scalper?” you ponder. It’s exactly how it sounds.
Geoffrey mows his lawn too dang short. He’s a bozo. He has no idea that mowing too short undoes all the good things he and his LCO are doing. He mistakenly believes mowing short buys him a few extra days in case he can’t mow on a seven-day schedule.
Before going any further with this blog, let’s be clear that we’re only talking about cool season turf species, such as Kentucky bluegrass, turf type fescue and perennial ryegrass. And we’re also talking about turf in full sun all dang day. Shady turf is a whole-nother subject! Warm season turf (zoysiagrass and bermudagrass) should be mowed as short as possible (yet another topic). Many of the little mowers are maxed out with a 3-inch height setting. Newer mowers, especially quality brands like Honda and Toro, can be set higher; professional mowers can be set up to at least 4 inches.
Here’s why cool season turf should be mowed as high as possible in the heat of summer. Cool season turf prefers to go dormant in hot and dry weather, but we push it with fertilizer and water, so we can keep it green and growing to enjoy its beauty. The growing point (crown) of cool season turf species is right at the surface of the soil. As such, mowing at LEAST 3 inches high provides a lot of shade at the soil surface, thus keeping the crown reasonably cool. Scalping is defined as anything below 3 inches, and mowing at 2.5 inches should be a felony! Scalped lawns let too much sunshine hit the soil surface, and the heat adversely affects the crown. When the crown of cool surface gets hot, it simply starts to peter out, preferring to go dormant.
In addition to a weak lawn there are a few weeds that always expose the scalpers, prostrate spurge and crabgrass. The weeds germinate because the turf is too weak. The photos below show this well.
There you have it! Cool season turf in full sun should be mowed at 3.5 inches when it’s above 85F. If your mowing service can’t give you 3.5 inches, fire them. If you mow yourself and your old beater mower can’t be raised to 3.5 inches–time for a new one!
Photos below: classic weeds in scalped turf, crabgrass and prostrate spurge. Note dormant turf, too.
For those of you wanting a nice flowering tree for full sun exposure, the flowering crabapple is hard to beat, but ONLY if you pick out the best cultivars. There are hundreds of varieties and cultivars of the crabapple, and most of them are actually quite crappy. You read that right–crappy! The inferior selections suffer from three bad foliar diseases (rust, scab and mildew) and some are susceptible to a virtually uncontrollable bacterial disease (fireblight). Too many of them have fruit that is too large for birds to consume, resulting in nasty messes and rotten fruits all over the sidewalk, driveway and patios. Those rotten fruits draw them dang yellow jackets, too. Horrible!
Too many homeowners abuse redbuds and dogwoods by planting them in a hot, sunny location (southwest, west and northwest exposures). Dogwoods abhor hot afternoon sun (3 to 7 PM) while redbuds can handle a bit more, but they won’t thrive with intense PM sun. Instead of planting these “woodland understory” species, plant a crabapple! Some crabs stay nice and small, while others can reach 30 ft tall and wide.
Here’s what you need to do. Visit the nurseries NOW. First, look for trees that still have leaves on them. If the leaves aren’t present, assume they suffered from disease and have dropped off. The owner of the nursery may try to tell you that simple water stress/drought is the reason for a lack of leaves, but don’t buy that line of B-S. Next, look for small fruits—about the size of a pea or just slightly larger. Marble-sized fruits are too big for most songbirds to consume. Finally, inspect the base of the tree for an absence of root suckers. It’s ok to have a sucker or two on the main truck, but NOT from the roots on the top of the root ball. If necessary, try to peel back the burlap on the top of the root ball to ensure that the existing suckers were not pruned of. You can easily feel the woody stubs. Heh now, keep your mind out of the gutter! Rootstock suckers are a symptom of either graft incompatibility or an aggressive rootstock, or both. They will develop all spring and summer long, and thus, make the tree ugly and result in a lot of maintenance headaches for you.
Let’s face it folks, this has really been a sucky summer. June was like July, July was like August, and August has been as horrible as usual. This tropical weather has placed turf under massive stresses from diseases and weeds. Cool season turf species (fescue, bluegrass, ryegrass) would rather take a prolonged siesta, but we water and fertilize it to keep it actively growing. Stressed turf simply can’t grow aggressively enough to combat these invaders. In contrast, weeds like crabgrass and yellow nutsedge love this crap! Both these weeds are evolutionarily-advanced “C4” species, meaning that they can thrive when temperatures get above 95F.
A quote often attributed to the great Green Bay Packers coach, Vince Lombardi, is appropriate at this point, who said, “The best defense is a good offense.” You’re thinking, what the hell does a legendary football coach know about turf? Well duh! Healthy, thick turf prevents weed seedlings from germinating. On the other hand, weak turf allows sunshine to hit the soil surface, stimulating weed seed germination. Lush turf, especially those swards mowed appropriately high in the summer, casts too much shade upon the soil surface, thus inhibiting weed germination.
These photos illustrate numerous issues, the first of which is dreadful application! Notice the very clean line of demarcation, which proves the effectiveness of the preemergent herbicide. The applicator (supposedly a PRO!) either ran short of product, or simply forgot to apply the herbicide on both sides of the sidewalk. The very uniform lines of control suggest an advanced spreading device. The homeowner needs to fire their asses! Find an LCO (Lawn Care Operator) that uses Dimension™ herbicide! But what if this was DIY? If this is the case, numerous explanations are offered. Probably the best guess is that the homeowner did not heed our advice to make a “double pass” application. He/she set the spreader setting too “heavy”, resulting in him not having enough product for the last 2 or 3 spreader swaths. Boo, hiss! Set your spreader on a “low setting” that allows you to make a double-pass application of every product. But wait! There’s another problem here. START every application along the edges of your concrete and asphalt surfaces, and in the street median. Make those passes first. Then start your double pass application. Pass 1 goes down at a certain direction and Pass 2 goes out at 45 to 90 degrees different. Turf growing along hard paved surfaces suffer from the highest weed pressure. So hitting these areas first ensures at least 2 passes with the spreader, and hopefully even 3 passes. The radiant heat load from paved surfaces increases the soil temperature in the adjacent soil. As a result, crabgrass germinates a full 10 to 14 days ahead of the rest of the lawn. In these areas the crabgrass seedlings grow sufficiently large that even Dimension herbicide can’t control them. These weeds simply germinated ahead of the preemergent application. The double whammy comes from the heat stress this turf suffers from in this area (reread the prior paragraph).
Another best practice is to make TWO applications of a preemergent herbicide, “just-in-case!” This was a “just-in-case” year! Heavy rainfall and high temperatures contributed to high microbial activity. Soil microbes actually “eat” pesticides—and they were quite hungry this year. Most LCO’s only make a single application and hope for the best. Many of them wait for the homeowner to call and bitch about crabgrass escapes. Care to guess what percentage of customers don’t even bother to complain?
Astute turf tenders wonder why the crabgrass in this image is chlorotic (yellowish) compared to the normal green color. It’s obvious that either the LCO or the homeowner has attempted to rectify the problem with a postemergent herbicide. Based upon the degree of chlorotic and bleached tissue, the herbicide applied was probably Tenacity® (mesotrione). This is a very new tool (3rd year of sale) for weed control in turf. It controls key broadleaf weeds and problem grassy weeds in cool season turf. It will damage bermudagrass and zoysiagrass and repeated use can actually control bermudagrass, if tank-mixed with Turflon® (triclopyr) herbicide. The best thing about Tenacity is that it doesn’t interfere with reseeding so it can be used now.
Mid-August is a great time of year to divide hostas and perennials because proper nighttime temperatures encourage rapid root development. Cut off all brown leaves when you replant new divisions. For hostas, it is actually safe to cut off all leaves, leaving “celery stalks,” especially if the leaves are severely bleached or bedraggled.