For those that live in the northern and transition states in the US, there are many cool-season grass types to choose from when trying to grow a healthy lawn. Two of the most popular cool-season grasses are Kentucky bluegrass and tall fescue; although they share some similarities, these grasses have different properties in their growth habits and maintenance requirements.
Kentucky bluegrass is fast growing and spreads to fill bare spots on its own, while tall fescue is slow growing and doesn’t spread in this way. This means that although the maintenance requirements are higher for Kentucky bluegrass, it has a better ability to self-repair from stress. Tall fescue, on the other hand, is more resistant to damage from stress in the first place. You can combine the two grass types to create a blend that offers the benefits of both species.
What is Kentucky Bluegrass?
Kentucky bluegrass is a cool-season perennial grass best suited for lawns throughout the northern states. This grass type has excellent hardiness throughout the winter months as it has a strong capacity to self-repair. However, Kentucky bluegrass has a limited tolerance for shade, with some varieties being more susceptible to stress from periods of heat and drought.
What is Tall Fescue?
Tall fescue is a cool-season perennial grass ideal for lawns in the northern and southern transition states. It is highly tolerant of a range of conditions including cold, heat, periods of drought, and shade. This grass can give you a thick, green lawn all year round. However, tall fescue has a limited ability for self-repair.
Key Differences Between Kentucky Bluegrass and Tall Fescue
We have summarized the key differences between Kentucky bluegrass and tall fescue grass in the table below.
|Property||Kentucky Bluegrass||Tall Fescue|
|Look & Feel||Kentucky bluegrass is deep green and feels soft to the touch.||Tall fescue is medium to dark green and feels coarse to the touch.|
|Hardiness||Kentucky bluegrass is particularly hardy in cooler climates.||Tall fescue is particularly hardy in warmer transitional regions.|
|How it Spreads||Kentucky bluegrass spreads through underground rhizomes and fills bare spots quickly.||Tall fescue produces tillers and forms bunches and does not spread to fill bare spots.|
|pH Requirements||Kentucky bluegrass needs a soil pH of 5.8 to 7.0.||Tall fescue needs a soil pH of 5.5 to 7.5|
|Fertilization Requirements||Kentucky bluegrass has higher fertilization requirements – on average it will need 3 to 6 pounds of nitrogen fertilizer per 1000 square feet throughout the year.||Tall fescue has lower fertilization requirements – this grass only needs 2 pounds of nitrogen fertilizer per 1000 square feet each year.|
|Watering Requirements||Kentucky bluegrass requires more frequent watering – it requires a minimum of 2 ½ inches of water per week in the hottest months.||Tall fescue requires less watering – it will need a maximum of 1 inch of water per week in the hottest months.|
|Mowing Requirements||Kentucky bluegrass requires frequent mowing.||Tall fescue requires less mowing.|
|Maintenance Requirements||Kentucky bluegrass is more expensive to maintain as it has higher mowing, fertilization, and watering requirements.||Tall fescue is less expensive to maintain as it requires less mowing, fertilizing, and watering.|
|Drought Tolerance||Kentucky bluegrass easily turns brown in drought and heat.||Tall fescue is highly tolerant of drought and heat.|
|Disease and Weed Tolerance||Kentucky bluegrass is vulnerable to diseases and weed growth.||Tall fescue is resistant to diseases and weed growth.|
Kentucky Bluegrass vs Tall Fescue
In this section, we will delve deeper into the differences between Kentucky bluegrass and tall fescue as turfgrasses.
Deep green blades that have a velvety texture. At full maturity, Kentucky bluegrass blades can reach 20 to 24 inches in height. The blades grow in a distinctive V shape, with each blade having a prominent midrib that runs up the center of the leaf. This grass spreads through underground rhizomes, meaning it will fill bare soil on its own.
Wide, dark green blades that appear shiny but feel coarse to the touch. Tall fescue is a bunch forming grass and spreads through tillers, which limits its capacity to become a dense lawn; overseeding would be necessary to fill bare spots. This grass can grow to be 4 to 12 inches tall when fully mature.
After seeding with Kentucky bluegrass, the grass will spread quickly to form a thick lawn. Overseeding won’t be necessary as the grass will fill bare spots on its own using its underground rhizomes. This seed is available in a variety of cultivators and you could mix it with other grass types to create a diverse blend. The best time to plant Kentucky bluegrass is in the fall, when temperatures reach 50 to 65°F.
Tall fescue lawns will likely need overseeding to keep them thick after planting. This grass type spreads by tillers, which are shoots that grow vertically from the base of the grass plants. Due to this mechanism, tall fescue has a limited ability to spread, therefore overseeding may be necessary to fill bare spots. The best time to seed tall fescue is in the late summer to early fall, when temperatures are around 60 to 65°F.
While both grass types benefit from 1 inch of water per week, Kentucky bluegrass may require more watering than tall fescue. Up to 2 inches of water per week may be necessary to keep Kentucky bluegrass green throughout the summer. The grass will go dormant and turn brown in prolonged periods of drought; however, thanks to its rhizomes, it will green back up quickly when conditions improve.
Tall fescue typically requires 1 inch of water per week, ideally split into two watering sessions. If the grass doesn’t receive enough water, the blades will curl and turn a dark blue-gray color. With that said, tall fescue is highly tolerant of periods of heat and drought.
Kentucky bluegrass requires more frequent fertilization to keep it thick and green compared to tall fescue. Lawns with Kentucky bluegrass need an average of 3 to 6 lbs. of nitrogen fertilizer per 1000 square feet of soil annually. These lawns need to be fertilized 3 to 4 times throughout the growing season, from spring to fall.
Tall fescue requires less fertilizer to keep it healthy. These lawns will only need roughly 2 lbs. of nitrogen fertilizer per 1000 square feet of soil annually. It’s best to fertilize tall fescue twice a year, doing so once in mid-September then again in November.
Due to its fast growth habit, Kentucky bluegrass will require more annual lawn maintenance than tall fescue. Regular maintenance activities like mowing, dethatching, watering, and fertilizing are necessary to counteract the abundant foliar growth; this makes Kentucky bluegrass more costly to maintain long-term. However, less maintenance is necessary in the way of overseeding thanks to this grass’ ability to spread on its own.
Tall fescue requires less annual maintenance as it grows more slowly and has shorter blades. Less mowing, dethatching, watering, and fertilization is necessary to keep this grass healthy, making it cheaper and less laborious to maintain.
Kentucky bluegrass is somewhat shade-tolerant, but it prefers full direct sun for at least 8 hours daily to thrive.
Tall fescue has a better tolerance for shade. You can plant this grass in areas that see full sun or partial shade throughout the day.
Compared to tall fescue, Kentucky bluegrass is less resistant to heavy foot traffic from people, pets, cars, or equipment. However, Kentucky bluegrass has an excellent capacity for self-repair; it will spread to fill bare spots created by traffic on its own.
Tall fescue is more resistant to foot traffic than Kentucky bluegrass and will withstand heavier use. The drawback is that lawns with this grass will require overseeding if damage does occur as tall fescue won’t fill bare spots on its own.
Can I Mix Kentucky Bluegrass and Tall Fescue?
Yes, you can mix Kentucky bluegrass and tall fescue to create a blend that will provide the benefits of both grass types. The grasses will grow well alongside one another without choking each other out.
These grasses complement each other in a blend as they differ in growth patterns; the Kentucky bluegrass will help to fill bare patches between the clump-forming tall fescue grass. The Kentucky bluegrass will keep your lawn looking full and thick due to its ability to self-repair quickly, while the tall fescue will improve your lawn’s shade resistance and reduce its need for regular watering, mowing, and fertilization.
How to Mix Kentucky Bluegrass and Tall Fescue for Best Results
For most transitional and northern lawns, the best seed blend is that which contains 10% Kentucky bluegrass to 90% tall fescue. Look for a disease-resistant seed blend to strengthen your lawn against fungal disease. If you already have one of these types of grass on your lawn, you can overseed with the other.