Perennial Ryegrass vs Annual Ryegrass – Differences + Comparisons

Both perennial and annual ryegrass are cool season grass great for establishing lawns in northern parts of the United States and for overseeding home lawns and sport fields with warm season grasses in the southern United States during fall. So, what the difference between perennial and annual ryegrass?

The main difference between perennial ryegrass and annual ryegrass is their lifecycle. Annual ryegrass has a short lifecycle that tend to last within a year while perennial ryegrass offers a continuous lifecycle year after year.

Perennial Ryegrass vs Annual Ryegrass – What’s the Difference?

Perennial and annual ryegrass are similar in many ways but have differences in their lifecycle, texture, height, the cost of the seed and few growing conditions.

Annual RyegrassPerennial Ryegrass
Has a one season lifecycleHas multiple season lifecycle
Coarse textured turfFine texture turf
Grass seed is less expensiveGrass seed is more expensive
Reaches 6 inches in heightReaches one foot in height
Thrives in zone 4 to 9Thrives in zone 5 to 7

Water Requirements

Both perennial and annual ryegrass have almost similar water requirements. Perennial ryegrass will require at least 1 inch of water per week while annual ryegrass may require 1 to1 ½ inches of water within the same period.

Temperature Requirements

Perennial ryegrass thrive within a temperature range of 55 degree Fahrenheit (12.8 degree Celsius) to 85 degree Fahrenheit (29.4 degree Celsius). Temperatures above this range will cause it to enter dormancy. Perennial ryegrass can survive short and mild freezing winters.

Annual ryegrass on the other hand can tolerate temperature range of 50 degree Fahrenheit (10 degree Celsius) to 90 degree Fahrenheit (32.2 degree Celsius). Extreme temperatures above or below this range can severely damage annual ryegrass.

Climatic Requirements

Perennial ryegrass is ideal for cool climate and transitional zones. It thrives well in United States department of Ag growing zone 5 to 7. It’s easy to maintain and prefer low traffic areas. While annual ryegrass is ideal for growing zones 4 to 9. It is not recommended in areas where the lawn is required for more than two years.

Appearance

Perennial ryegrass has a fine texture with a bright green appearance while annual ryegrass has a course texture with a bright green appearance. Annual ryegrass will resemble grass-like twigs at the end of the cycle rather than a lush texture.

Lifecycle

Perennial ryegrass has long lifecycle when maintained properly, it will continue to grow health year after year. On the other hand, annual ryegrass has a short lifecycle. You have to keep track on when annual ryegrass dies and keep on reseeding it yearly at the end of the season.

Soil Requirement

Perennial ryegrass thrives in well-drained soil with a pH range of 5.5 to 7.5. Due to its shallow roots, it is difficult to penetrate compact clay or loamy soil. Dry sandy soil is ideal for perennial ryegrass. While annual ryegrass prefer well-drained sandy soil with a pH range of 6 to 7.

Seed cost

Perennial ryegrass seed is more expensive as compared to annual ryegrass seeds. However, you will have to keep on buy annual ryegrass seed annually. Therefore, you may end up spending more money of annual ryegrass seed than perennial ryegrass seed after several years.

Mowing needs

Tall perennial ryegrass require regular mowing to maintain it at 1.5 to 2.5 inches. On the other hand, annual ryegrass can grow to a maximum height of six inches. Mow to maintain it at a height of 1.5 to 2 inches.

Pros and Cons of Perennial Ryegrass

Perennial ryegrass offers a great versatility, can be used as livestock forage, green lawn grass in winter when over-seeded with a warm-season grass and for erosion management among other uses. Like any other type of grass, it has its own pros and cons.

Perennial Ryegrass Pros

  • Great wear tolerance: Perennial ryegrass has a great wear tolerance high and low temperatures. It is ideal for colder climatic areas and transitional zones that experience fluctuations in temperature.
  • Pests and disease tolerance: Perennial ryegrass has a moderate tolerance to diseases lie mold, mildew, moss and algae in moist areas as compared to other types of grasses. Furthermore, it’s also tolerance to pests like webworms and thrips.
  • Establishes rapidly: Unlike other types of grass, perennial ryegrass germinates and establish within a short period of time.  It’s a high yielding grass with a long growing season.
  • Excellent forage crop: Perennial ryegrass can be planted as a fodder crop for animals. When harvested, it can stored as hey to be feed on domestic animals.

Perennial Ryegrass Cons

  • Difficult to eradicate: Although bunch forming, perennial spreads faster through tillers. It is hard to control it when spread to garden beds, pathways and driveways. Further, it can easily get out of control when not mowed regularly.
  • Hard to maintain: Perennial ryegrass require extensive care as compared to other types of grass. It require regular fertilizing, watering and mowing.

Pros and Cons of Annual Ryegrass

Annual ryegrass has the following benefits and negatives

Annual Ryegrass Pros

  • Control soil erosion: Annual ryegrass germinates and grow rapidly to cover the ground. It offers a natural solution to water runoff and wind erosion.
  • Chokes out weeds easily: With fast growth rate, annual ryegrass is able to smother out the weeds. It can also be used as a natural pre-emergent due to its allelopathic properties.
  • Germinates Fast: Annual ryegrass has a fast germination rate of 5 to 10 days. With fast germination and growth rate, this species of grass is able to mature fast and produce seeds at the end of the season when not mowed.
  • Tolerance to foot traffic: It has a course texture that is ideal for high foot traffic areas in your lawn such as children and pet playing areas. It also has a high wear tolerance as compared to other grass species.

Annual Ryegrass Cons

  • Require regular re-seeding: Annual ryegrass has a short lifecycle. You have to keep on re-seeding your lawn every year at the end of the season. It’s tiresome and time consuming to establish a new lawn.
  • Turf Degrades over time: Annual ryegrass is likely to degrade towards the end of the season to resemble grass-like twigs instead of a lush green lawn.

Which is better between Perennial and Annual Ryegrass

A choice between perennial and annual ryegrass depends on your needs. Each of the two species has its own advantages and disadvantages. Both are cool-season grass that can be over-seeded with a warm-season grass to provide a green lawn in winter.

However, perennial ryegrass is the best choice to over-seed with a warm-season grass due to its long lifecycle. You are not required to re-seeding your lawn at the end of every season as it is the case with annual ryegrass.

Both species have almost similar maintenance routine. However, while you are required to mow the annual ryegrass to reduce competition with vines, it is different with perennial ryegrass. It require frequent mowing to maintain the height of 1.5 inches to 2.5 inches.

Final Thoughts

The biggest difference between perennial and annual ryegrass is their lifecycle. Perennial ryegrass offers a continuous growth cycle year after year while annual ryegrass will require re-seeding at the end of every season. Choosing the best between the two will depend with your preference.

References:

  1. The University of Tennessee: Turfgrass Selection Ryegrasses
  2. University of Wisconsin – Extension: Ryegrass Types for Pasture and Hay
  3. Pennsylvania State University Extension: Ryegrass

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