OKC

July Lawn & Landscape Tips

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Shocker!  We have gone a whole week without rainfall in the Oklahoma City metro area.  This is the first week since mid-February that we have not had some precipitation. Normal annual rainfall in our area is around 35”, compared to 55” we have received in the last 365 days. 

If there is any practice that has been reinforced this year is important to plant a little high and make sure you have positive drainage away from your plant materials.  During periods of excessive moisture, plants with poor drainage, or ones that are planted too low, even if it was years ago, will be weakened by root damage.  Plants need the right balance of air and moisture in the soil.  When excessive water robs the soil of space for air, roots start to rot.  Rarely do know there is a problem until temperatures start to rise and the plant doesn’t have enough root system to supply the plant with needed moisture.  This week we looked at several plants that are struggling with root damage from the excess moisture. 

What is important for lawn and landscape now that temperatures are in the low to mid 90s and less rain is in the forecast?

Let’s take a look…

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Mowing – For warm season turfs (Bermuda and zoyia) gradually raise the height of your mower. Bermuda should be mowed between 1.5” to 2.5” during the summer heat. Fescue, cool season turf, should be maintained at its maximum height, 3” to 3.5” now. The more leaf space you have the more drought resistant your lawn will be. Mow often enough that you only remove 1/3” of the grass each time. For healthy, irrigated, and fertilized Bermuda, if possible, mow every 4-5 days for the best lawn. If you are mowing often enough you are only removing 1/3 of the growth, don’t catch the clippings. Grass leaves are mostly water and nitrogen and they break down very quickly into the soil. If your lawn has a brown cast to it after you mow, you are cutting below the leaves and into the stems. Stems do not break down quickly and can lead to thatch build-up, so if this is the case, it is best to bag when mowing.

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Watering – Your lawn and landscape needs at least 1” to 1.5” of moisture per week during the hottest periods of the summer. Water on an odd/even schedule early in the morning – before dawn. Avoid watering in the evening. Remember, deep soakings are always best. Shallow watering creates shallow roots dependent on more frequent watering. Monitor local rainfall and turn irrigation off when there is sufficient rainfall. Newer plantings will require additional watering until they have established roots.

Brown Patch – We are starting to see brown patch on Fescue. Brown patch occurs when there is excessive moisture, high humidity, and/or high due points when summer temperatures are in the 90s. Brown patch is worse in areas with dense shade and/or low wind movement. Anytime the leaf blades of your fescue stay wet for more than 6 hours at a time in the summer, brown patch is unavoidable. The temptation is to water fescue more frequently in the summer. It is common for us to find fescue lawns with the irrigation set to run morning and night creating the perfect conditions for the disease to spread. If you have heavy shade and/or low wind movement (most smaller backyards) water after sunrise and no more than every other day. Resist the urge to water more. Your fescue is not dying due to summer heat, it is struggling with brown patch. As a part of our 7 Step Lawn Care Program for cool season lawns, lawns with brown patch will receive a fungicide to help suppress the disease.

Fertilizer – Because warm season grasses are actively growing, they need feeding during July. We try to use a fertilizer with close to a 3 to 1 to 1 of nitrogen (N), phosphorus (P), and potassium (K).  Most of our soils have plenty of phosphorous and potassium, but nitrogen needs to be replaced.  July is a great month for turf development and a thick, healthy growing lawn is the best defense to weeds. Do not fertilize fescue lawns now.  As a cool season grass, fertilizer in the heat of the summer on fescue will cause damage.

Weed Control – If you are on a regular lawn care application program, and if your first application was made prior to the first of March, you shouldn’t be experiencing many summer annual weeds.  But, with the excessive rain, we have seen some breakdown of pre-emergent herbicides, and a lot of nut sedge.  Nut sedge thrives in tight, wet soils – this year is the perfect storm for nut sedge.  If you didn’t get an early pre-emergent, you most likely have a good crop of crabgrass now. Controlling weeds in the heat of the year often can cause more damage to the turf than is beneficial.  It is important that label instructions are always followed when spraying for weeds.  Don’t over apply.  Again, what is most important in July is developing a thick, healthy turf.  If you are too aggressive on weeds now you will have weak spots that are more susceptible to weeds in the future.  

Shrub Pruning – Selective pruning and light shearing should be practiced during the summer heat. Major pruning needs to wait for now. Avoid any pruning or shearing on spring blooming plants because most likely you will be removing flower buds and reducing the show next spring. 

Aphids

Insect Watch – The first step to healthy plants is inspecting them regularly and then treating as needed. If you attempt to treat on a schedule, you will find that you often will miss the target pest. This year is a prime example. Bagworms and aphids have both been late to the game. With bagworms, by this time of the summer they are usually getting big and very noticeable. This week I noticed a few needle evergreens with very small bagworms aggressively feeding. Aphids also are late but are now aggressively attacking plants. Start watching for spider mites. They thrive in hot, dry conditions. They gather on the underside of your plant leaves and do damage by sucking sap from the leaves. They will leave small holes and eventually your leaves will look yellow and weak. They are very small and can be very hard to see. Take a white sheet of paper, place it below the leaf and lightly shake the leaf. If you see small specs of red, yellow and brown on the paper and they start moving around, it isn’t dust and dirt you are seeing, it is spider mites. Organic controls include insecticidal soap, predatory insects, and neem oil. If you subscribe to our Tree & Shrub Care program, we are inspecting each time we visit your landscape and treating as needed.

Bag worms

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Grub Worm Control – If you have experienced grub damage in the past, or if you have noticed a lot of June bugs around your landscape, July through August is a good window to apply an application for control. Grub worms are the larva form of the June bug. June bugs have laid their eggs and they are hatching now. Grubs are easiest to control when the new grub is small and feeding close to the surface in July and August.

Tree Leaves – Expect some leaf drop on deciduous trees in the summer heat.  Because of the abundant rainfall this year, trees are loaded with foliage and we may experience a lot of leaf drop should July and August turn out hot and dry.  Some leaf drop is a good thing as the tree naturally adjusts to the amount of moisture it is receiving.  The fun fact about most trees is they have a secondary set of buds.  If they are stressed, they naturally drop leaves to survive, and then re-bud as they recover.

If you have any lawn or landscape concerns, needs or questions, please give us a call – (405)367-3873.

Lorne Hall

Hall|Stewart