Warm Season vs Cool Season Ornamental Grasses

It’s almost spring, and already some plants are breaking dormancy in the warmer growing zones and mild winter climates. Just like there are morning people, and then the rest of us, plants have their own timeline on when they are ready to shake off their sleep and jump out of their winter beds.

In terms of your Grasses - both Ornamental and Turf Grass - when each type prefers to get going in the spring and what your hardiness zone is can mean the difference between fields of green, and I-think-it-died-brown.

Warm-Season vs. Cool-Season Grasses
Cool-Season Grasses
Warm-Season Grasses
The In-Between Zones
Lush Green Grass!

Warm Season vs. Cool Season Grasses

Whether you are talking about Ornamental Grass, Native Prairie Grass, or Lawn Grass, you need to know what type you are dealing with to know how to best care for it and know what to expect as it grows.

This will directly relate to when you can expect to see new growth in the spring, when it’s best to fertilize and water your plant. It also relates to when you can expect dormancy and when to plant them in the fall. You’ll also know which to choose for your Growing Zone and climate, so you will have the greenest landscape possible!

Ornamental Grass cold vs warm season

Cool Season Grasses

Some Grasses are the morning person type of grass and will start to grow the moment the soil begins to warm. These are the cool-season grasses, and they thrive in those cooler temperatures of spring and fall.

Growing best throughout USDA growing zones 2 through 6, cool-season Grasses handle severe cold, ice, and shorter growing seasons, jumping out of the ground in a hurry, knowing that the summer heat is fleeting and cold fall weather will once again be upon them.

Kentucky Bluegrass

Their ideal temperature range for growth is between 65 - 80°F, putting on most of their growth in the spring, taking a break in the summer heat, before growing again in autumn.

The best planting time for these Grasses - both Turf and Ornamental - is in the fall. This gives the plant, plugs, or seed plenty of time to establish before enduring summer heat stress. It will have a larger root system to take up water and grow deep enough by next summer to stay cool.

Some examples of Cool-Season Grasses are Annual and Perennial Ryegrass, Bentgrass, Rough Bluegrass, Kentucky Bluegrass, Tall Fescue, and Fine (Creeping) Fescue. On the Ornamental Grass side are Overdam Feather Reed, Karl Foerster, and Desert Plains Grasses, just to name a few.

Karl Foerster Grass

Cool-Season Grass Benefits

Cool-season Grasses tolerate cold weather and harsh winters beautifully! Many can handle a bit more shade and can take on higher traffic without issues.

With Rye coming out on top for foot traffic
Fescues are great for shade
Both Tall Fescue and Fine Fescue are adept at handling heat, drought, and cold
Bluegrass is the most popular for the lawn, so long as it is in a sunny location

You will often see many cool-season Grass seed mixtures include a combination of varieties to cover every possible contingency your lawn may face! From sun to shade, to heat and cold, that way your yard looks best for as long as possible throughout the growing season.

This is the same with Ornamental grasses, planting a mix will ensure you’ll always have something nice in your garden at any point and throughout any type of weather!

The slight downside with cool-season Grasses is that in the heat and during periods of extended drought, they will need extra moisture to keep during rising temperatures and dry conditions, so they remain looking good.

To keep your grass green, establish a regular watering schedule of 1 inch of water per week, including rainfall, to maintain a gorgeous green lawn.

Warm Season Grasses

he lower portion of the US, typically zones 7 through 10, needs to plant warm-season Grasses. These Grasses hit the snooze alarm a few times and wait until temperatures are just right. The downside is that these Grasses look as dead as a doornail until the soil temperatures warm up enough for them to break dormancy! Remaining brown throughout the entire winter months, sometimes until late spring, or even early summer, before they start to grow.

Warm-season Grasses typically flourish between 80 and 95º and put on the most growth. But it will go dormant when temperatures are consistently below 60°F. For most of the southern third of the US, it's best to plant these warm-season grasses.

Warm-Season Grass Benefits

Warm-season Grass plants are resilient in the heat, highly xeric and drought-resistant, handle occasional cold well, and thrive in both higher humidity or more arid conditions than cool-season Grasses do. Warm-season Grasses take off and just soak up the heat of summer!

With an extensive and tough root system and the ability to stay green despite heat and drought, warm-season grasses just shine in as much sun and heat as you can give them!

Some examples of warm-season Grasses are Switch Grass, Carpet Grass, Buffalo Grass, St. Augustine, Bermuda, Zoysia, Centipede, and Bahia Grasses. There are many warm-season Ornamental Grasses, and a few are Miscanthus, Schizachyrium (Bluestem), and Panicum family members.

All these warm-season Lawn and Ornamental Grasses do fantastic in the heat and thrive in both the arid Southwestern US and the humid climates of the Southeast US.

Bahia grass comes out on top for the high humidity tolerance in the southeastern US
Bahia and Centipede Grasses have good foot traffic resistance
Many Native types, like Buffalo Grass, have roots extending several feet into the soil
Bermuda, Zoysia, and St. Augustine Grasses are so dense, they handle drought best
St. Augustine is recommended for saline and coastal conditions
Bermuda and Buffalo are recommended for overseeding and plugs
St. Augustine and Zoysia are great when installed as plugs

The downside is that once those cooler temperatures settle in, you’ll be left with a brown-looking lawn later into the spring, while your neighbors' cool-season lawns are already looking green and lush.

But the joke's on them - while their lawn is struggling and gasping in the heat of summer, your lawn will look fantastic! When drought and sizzling temperatures hit, you and your water bill will have the last laugh!

The In-Between Zones

If you live somewhere in the middle of the US, you get the cold winter weather and the brutal summer heat. Therefore, you are in what is called the Transition Zone. Here you see the best (and worst) of both worlds! So you need a Turf-Grass or ornamental-grass variety that will either stand up to it all or plant a mixture of both, to always have something nice and green, regardless of where and what.

Tall Fescue seems to do fantastic in these Transitional states
Bermuda and Zoysia, too, due to their cold tolerance and ability to handle drought.

Transition Zones states can also look for a seed mixture of cool and warm-season grasses to create a dream lawn that stays nice and green all growing season long! Check with your local County Extension Office to find out which lawn and ornamental grass plants do best in your specific area!

Best of Both Worlds?

Buffalo Grass is a fantastic Native choice for these middle states due to its tolerance for about anything these varied climates and wildly changing weather zones can throw at it! Legacy Buffalo Grass is a native selection that can handle a wide range of climates and conditions from USDA Hardiness Zones 2 all the way up to zone 10! Another advantage of Buffalo Grass is that they are soft and short, requiring far less mowing and upkeep! This choice is a fantastically xeric and eco-friendly option!

Lush Green Grass!

Don’t hurry your late-rising warm-season Grass along and have some patience! It will show up when temperatures are right. Just because cool-season Grasses have the advantage in the spring and may look better now, planting a mixture of both will give you and your landscape the best of both worlds! Cool-season Grass has its own advantages in the harsh winter, returning year after year of brutal cold and snowpack, and acting as if nothing happened once it all melts away!

So if your Grass is still looking dead as a doornail in your landscape might just be sleeping in; don’t dig it up just yet, and compost it; it's just a warm-season Grass waiting for temperatures to rise before it gets growing!

Check out all of Nature Hills' quality Ornamental Grass and Turf Grass available today and make your side of the fence the greenest!

Happy Planting!

Frequently Asked Questions

Is tall fescue a cool season or warm season grass?

Tall fescue is a cool-season grass that thrives in USDA growing zones 2 through 6. Like other cool-season grasses, it performs best when temperatures are between 65 and 80 degrees Fahrenheit, putting on the most growth during spring and fall while going semi-dormant during the heat of summer. For best results, plant tall fescue in the fall to give it time to establish a strong root system before facing summer heat stress the following year.

Does grass stop growing in extreme heat, and how do I keep it healthy?

Yes, cool-season grasses like Kentucky Bluegrass and Tall Fescue naturally slow or pause growth when temperatures climb above 80°F, entering a semi-dormant state to conserve energy during summer heat. This is completely normal behavior, not a sign that your lawn is dying. To keep your grass as healthy as possible through this period, make sure it has developed a deep root system by planting or overseeding in fall, which gives it the best chance of bouncing back once temperatures cool. During summer stress, avoid heavy fertilizing, mow at a higher blade setting to reduce moisture loss, and water deeply and infrequently to encourage roots to reach for moisture further down in the soil.

Can warm season grass survive temperatures above 100 degrees?

Warm season grasses are built for heat and generally handle high temperatures well, thriving in their ideal range of 80 to 95 degrees Fahrenheit across USDA zones 7 through 10. Most warm season varieties like Bermuda, Zoysia, and St. Augustine can tolerate temperatures above 100 degrees, though prolonged extreme heat combined with drought stress can cause them to go dormant or suffer damage. To keep your warm season lawn healthy during intense heat waves, water deeply and infrequently, allowing moisture to reach 6 to 8 inches into the soil, and avoid fertilizing during peak summer stress periods.

How do I tell whether my lawn needs warm season grass or cool season grass?

The key factor is your USDA hardiness zone and local climate. Cool-season grasses like Kentucky Bluegrass, Fescue, and Ryegrass thrive in zones 2 through 6, where summers are mild and winters are cold, with ideal growing temperatures between 65 and 80 degrees F. Warm-season grasses are better suited to the heat and humidity of zones 7 and above, where summers are long and hot. Check your USDA growing zone at planting time, then browse Nature Hills' grass selection filtered by zone to find the right match for your lawn.

What is the best time of year to plant warm season grasses versus cool season grasses?

The best time to plant cool-season grasses, which thrive in USDA zones 2 through 6, is in the fall, giving roots time to establish before summer heat arrives. Warm-season grasses, by contrast, should be planted in spring once soil temperatures have warmed, as they actively grow during the heat of summer. Regardless of type, timing your planting correctly gives your grass the strongest possible root system before it faces its most stressful season.

Which grass type performs better in the transition zone between warm and cool climates?

In the transition zone, which typically falls around USDA zones 6 and 7, neither warm-season nor cool-season grasses perform perfectly year-round, but tall fescue is often the most reliable cool-season option due to its greater heat tolerance. Warm-season grasses like Zoysia or Bermuda can also work in these zones, staying green through summer but going dormant in winter. For the best results in a transition zone, consider overseeding warm-season turf with a cool-season ryegrass in fall to maintain year-round color, or consult your local extension office to identify which specific varieties have proven most successful in your area.

How often should I water warm season grass compared to cool season grass?

Warm season grasses are more drought tolerant and typically need watering only once or twice per week during their active summer growing period, while cool season grasses may need more frequent watering in summer since heat pushes them toward dormancy and stress. Cool season grasses do most of their growing in spring and fall when natural rainfall often reduces the need for supplemental irrigation, but they require consistent moisture during summer heat to prevent browning. A general target of about one inch of water per week applies to both types, but adjust based on rainfall, soil type, and your specific growing zone. Monitor soil moisture regularly and water deeply and infrequently to encourage deep root development in both grass types.

When should I mow warm season and cool season grasses for the best results?

Warm season grasses should be mowed regularly during their active growing period in summer, keeping them at their recommended height, and you should stop mowing as they head into fall dormancy. Cool season grasses thrive with mowing in spring and fall when temperatures are between 65 and 80 degrees Fahrenheit, but you should raise your mower deck height during summer heat to help the grass stay cool and reduce stress. As a general rule, never remove more than one-third of the grass blade at a single mowing, regardless of grass type. Match your mowing schedule to your grass type's active growing season for the healthiest, most resilient lawn.

What fertilizer schedule should I follow for warm season versus cool season lawns?

Cool-season grasses like Kentucky Bluegrass and Tall Fescue thrive in zones 2-6 and should be fertilized primarily in early fall and again in late spring, avoiding summer applications when these grasses go semi-dormant under heat stress. Warm-season grasses, which peak in zones 7-10, should be fertilized in late spring once soil temperatures reach around 65°F and again in midsummer to support their active growing season. Avoid fertilizing warm-season grasses in fall, as this can stimulate tender new growth that is vulnerable to frost damage. Match your fertilizer timing to your grass type's natural growth cycle for the healthiest, most resilient lawn.

How do I switch from a cool season grass lawn to a warm season grass lawn?

Transitioning from a cool-season to a warm-season grass lawn requires killing off the existing turf completely, typically in late spring once soil temperatures reach at least 65°F, which is also the ideal time to establish warm-season varieties. Use a non-selective herbicide or solarization method to eliminate the old grass, then wait at least two weeks before planting your warm-season seed, plugs, or sod. This switch makes the most sense for gardeners in USDA zones 7 through 10, where summer heat makes cool-season grasses struggle anyway. Time your new planting for late spring to early summer so the warm-season grass has a full growing season to establish before its first dormancy period.

What Are Warm Season And Cool Season Grasses?