Perennial and annual ryegrass are cool-season grasses for establishing lawns in northern parts of the United States. As grasses that stay green in winter, Perennial and annual ryegrass are also used to oversee warm-season grass for winter colour. So, what’s 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 lasts within a year, while perennial ryegrass offers a continuous lifecycle year after year.
Although similar in many ways, perennial and annual ryegrass have different lifecycles, textures, heights, seed costs, and a few growing conditions.
| Annual Ryegrass | Perennial Ryegrass |
| It has a one-season lifecycle | It has a continuous season lifecycle |
| Forms a coarse textured turf | Form a fine texture turf |
| Its grass seed is less expensive | Its grass seed is more expensive |
| Reaches 6 inches in height | Reaches one foot in height |
| Thrives in zone 4 to 9 | Thrives in zone 5 to 7 |
Perennial Ryegrass vs Annual Ryegrass – Detailed Comparisons
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 thrives within a temperature range of 55 degrees Fahrenheit (12.8 degrees Celsius) to 85 degrees Fahrenheit (29.4 degrees Celsius). Temperatures above this range will cause it to enter dormancy. Perennial ryegrass can survive short and mild freezing winters.
On the other hand, annual ryegrass can tolerate a temperature range of 50 degrees Fahrenheit (10 degree Celsius) to 90 degrees Fahrenheit (32.2 degrees Celsius). Extreme temperatures above or below this range can severely damage annual ryegrass.
Climatic Requirements
Perennial ryegrass is ideal for cool climates and transitional zones. It thrives well in the United States Department of Ag, growing zone 5 to 7. It’s easy to maintain and prefers 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 coarse 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 a long lifecycle. When maintained properly, it will continue to grow healthy year after year. On the other hand, annual ryegrass has a short lifecycle. You have to keep track of 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.
On the other hand, Annual ryegrass prefers 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 buying annual ryegrass seeds annually. Therefore, you may spend more money on annual ryegrass seed than perennial ryegrass seed after several years.
Mowing needs
Tall perennial ryegrass requires 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 the height of 1.5 to 2 inches.
Pros and Cons of Perennial Ryegrass
Perennial ryegrass offers great versatility and can be used for livestock forage, green lawn grass in winter, and 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 at 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 problems like mildew, moss and algae in moist areas compared to other grasses. Furthermore, it’s also tolerant to pests like webworms and thrips.
- Establishes rapidly: Unlike other types of grass, perennial ryegrass germinates and establishes 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 be stored to be fed to domestic animals.
Perennial Ryegrass Cons
- Difficult to eradicate: Although bunch forming, perennial spreads faster through tillers. It is hard to control 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 requires extensive care compared to other grass types. It requires 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 grows rapidly to cover the ground. It offers a natural solution to water runoff and wind erosion.
- Chokes out weeds easily: With a fast growth rate, annual ryegrass is able to smother out the weeds. Due to its allelopathic properties, it can also be used as a natural pre-emergent for weeds.
- Germinates Fast: Annual ryegrass has a fast germination rate of 5 to 10 days. With a fast growth rate, this species of grass can mature fast and produce seeds at the end of the season when not mowed.
- Tolerance to foot traffic: It has a coarse texture ideal for high foot traffic areas on 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 must keep 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 warm-season grass to provide a green lawn year-round.
However, perennial ryegrass is the best choice to over-seed warm-season grass due to its long lifecycle. You won’t be re-seeding your lawn at the end of every season, as is the case with annual ryegrass.
Both species have almost similar maintenance routines. However, while you must mow the annual ryegrass to reduce competition with vines, it differs from perennial ryegrass, which requires frequent mowing to maintain a height of 1.5 inches to 2.5 inches.
Also Check: How to make Ryegrass thick faster
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 on your preference.
References:
- The University of Tennessee: Turfgrass Selection Ryegrasses
- University of Wisconsin – Extension: Ryegrass Types for Pasture and Hay
- Pennsylvania State University Extension: Ryegrass