The chances of me writing on the dangers of too much rain on the 4th of July weekend are very slim, but that is where we find ourselves this week.

With the 7 day rainfall amounts ranging between 5-12” in the Oklahoma City area, the year of unusual weather patterns continues. Since October 2020, we have experienced metro wide tree damage, major plant damage due to record cold temperatures, slow warm season turf development due to a cooler than normal April and May, and now the challenges of too much rain to start the month of July.

It may be difficult to comprehend, but there is a point where your lawn and your landscape will suffer from too much water.

Roots are the foundation of a healthy plant.

They are the primary source of water, nutrients, and oxygen.

Yes, oxygen. Plants breathe through their root system.

Plants, just like humans, can drown when water replaces air.

One of the biggest problems of too much water is seen on fescue lawns. There is a misconception that fescue lawns need a lot more water which would lead you to believe that this week’s weather pattern is perfect for a fescue lawn heading into July.

But, the truth is that during the summer months, too much water can be the biggest problem a fescue lawn could face!

The weather patterns over the last 9 months has made us question everything we thought we knew about lawn care. This picture is a good demonstration of just how crazy it is. In the shoot is a winter annual weed, poa annua, and a late summer annual weed, spurge.  In over 30 years in the industry, Tom & I, have never seen these two weeds existing at the same time. Poa annua should have died out by now and spurge shouldn’t be growing yet. It’s a crazy year! — The weather patterns over the last 9 months has made us question everything we thought we knew about lawn care. This picture is a good demonstration of just how crazy it is. In the shoot is a winter annual weed, poa annua, and a late summer annual weed, spurge. In over 30 years in the industry, Tom & I, have never seen these two weeds existing at the same time. Poa annua should have died out by now and spurge shouldn’t be growing yet. It’s a crazy year!

Brown Patch is the most common disease of fescue in Oklahoma. The pathogen (Rhizoctonia solani) that causes brown patch prefers warm temperatures and requires excessive moisture. The last 7 days have been the perfect breeding ground for an outbreak of brown patch in Oklahoma.

The disease first appears in areas that are wet. It is most likely to develop when humidity is high and/or excessive soil moisture prevails and warm temperatures during the day in the 90’s or nighttime temperatures in the 70’s persist. Poor soil drainage, lack of air movement, heavy shade, cloudy weather, excessive dew, high humidity, daily watering, and watering at night will all increase the development of the disease.

On closely mowed bentgrass, commonly used for putting greens, the symptoms appear as somewhat circular patches. But, in the home lawn where grasses are taller, such as fescue and rye, brown patch appears as irregularly shaped larger areas of thinning, brown to yellow grass blades. Close inspection of leaf blades will reveal small, irregular, tan leaf spots with dark-brown borders. Brown Patch will be more severe in fescue that has had excessive nitrogen fertilizer in the summer.

Close inspection of leaf blades will reveal small, irregular, tan leaf spots with dark-brown borders.

Brown patch disease loves mornings when there is a heavy dew.

Brown patch disease in fescue appears as irregular areas that lead you to believe the lawn may not be getting enough water.

With no fescue species entirely resistant to brown patch, brown patch will always be a problem when conditions are right for the development of the disease.

A close look at the leaf blades in this area of fescue that is turning slightly brown and thinning reveals the presence of brown patch disease.

Turf Talk chats about brown patch.

With no fescue species entirely resistant to brown patch, brown patch will always be a problem when conditions are right for the development of the disease.

But there are things that can be done to minimize the chances of brown patch being a problem:

Selecting tall fescue varieties with a high resistance to brown patch is a critical first step. We recommend using a fescue blend with at least three varieties. Additionally, look for a mixture specifically for our area. The mixture we use to overseed fescue in the fall includes varieties that show high resistance to brown patch.
Do not use high rates of nitrogen fertilizer on fescue when temperatures are prime for brown patch during the summer months. Apply no more than ½ lb. of nitrogen per 1,000 square feet when conditions are right for brown patch development. The disease readily attacks the lush growth of grass promoted by nitrogen. During the early summer, fertilize fescue with a low nitrogen fertilizer containing higher amounts of phosphorus and potassium to strengthen the root system then do not fertilize again until temperatures begin to cool in September.
Avoiding prolonged periods of leaf wetness will drastically reduce the severity of brown patch. When temperatures are warm, if fescue stays wet for more than 5-6 hours at a time, the disease will be present. Do not water daily. Water only when needed and only in the early morning. Deep soakings every other day is best. The goal is to get 1 ½” of water on fescue per week by watering no more than 3 times.

Keep the lawn mowed regularly at the proper height. Fescue should be mowed at 3 to 3 ½” in the summer. Lower mowing will increase disease severity.

Do all you can to provide good drainage. Annual aeration in the fall will help.
Overseed fescue in the fall. Avoid spring seeding of fescue. Brown patch is more aggressive on young fescue while mature fescue is more resistant. It is common for spring seeded fescue to struggle with brown patch.
Have your soil tested every couple of years. Brown patch will be more severe when the soil is not healthy, if the pH is too high or too low, or nutrients are out of balance.
The best way to prevent brown patch is to eliminate areas where the disease will thrive. Consider making changes to the landscape in areas with poor air circulation and dense shade. Small turf areas surrounded by structures, fences, and heavy landscaping are brown patch prone. You may find removing the turf and extending the landscape or planting groundcovers a better option.

Areas of dense shade and poor air circulation may be better served with ground covers such as liriope.

Most importantly….turn your irrigation off for the next few days. Allow a few days for your lawn and landscape to dry out — especially if you have fescue.

If your fescue is not looking its best, don’t assume it needs more water. Brown patch will lead you to believe the lawn is too dry. Before you start watering, inspect the leaf blades for evidence of the disease and check the soil to see if it is dry. It is common for us to receive a call reporting “I just can’t get enough water on my fescue to keep it alive…” only to make a site visit to find a thinning fescue lawn struggling with self-induced brown patch from overwatering.

Anytime you have questions or concerns about your lawn issues, give us call. We enjoy helping you have a lawn and landscape you can enjoy!

Lorne Hall

Hall | Stewart Lawn + Landscape

(405) 367-3873