Poa

( POH - uh )

At-A-Glance Information

This genus of perennial and annual grasses includes species commonly called Bluegrass or Meadow Grass. They need full sun and regular water to perform well in the garden. These cool-season grasses are native to Europe, but have naturalized themselves in North America. They are commonly grown in drought tolerant or native landscapes. They can help stabilize soil on sloped areas of the garden, or provide filler in rock gardens. These grasses are rarely used intentionally as a residential lawn, and are considered aggressive weeds of lawn areas, causing patchy die-off in lawns during summer heat.

poa Species and Varietals

Poa is a genus of 570 species of grasses in the plant family Poaceae. The grasses in this genus are related to those in Alopecurus (Foxtail Grasses). The best growing zones for Poa are USDA hardiness zones 3-11. To find your zone, click here: Zone Map.

Poa annua (Annual Bluegrass, Annual Meadow Grass, Speargrass, Wintergrass)
This species is an annual, and is commonly found in lawns as a weed. It is a bright green, soft grass that thrives in moist, cool conditions. This species produces small, white feathery seed heads and typically dies in summer heat, leaving bare, unsightly patches in grass areas. Individual plants reach up to between 1 and 18 inches tall. This species is considered invasive across temperate, sub-Arctic, and urban regions around the globe.

Poa pratensis (Kentucky Bluegrass, Smooth Meadow-Grass, Common Meadow-Grass)
This perennial grass does well in USDA hardiness zones 3-8 or Sunset growing zones A1-A3, 1-3, 4-11 and 14-17, performing best in cool, humid regions. It has a blue-green hue to it, and many varieties are available as sod. Mown to 2-2.5 inches tall, this species can be used alone or alongside other lawn grasses. It is considered invasive in California, the northern Great Plains, Pacific Northwest, and northeastern regions of the United States and various areas of Canada.

Poa trivialis (Rough-Stalked Bluegrass, Roughstalk Bluegrass, Rough Bluegrass, Rough Meadow-Grass)
This perennial grass does well in USDA hardiness zones 3-7 or Sunset growing zones A1-A3, 1-11 and 14-17. It has a fine texture and is light green. This grass can reach up to between 10 and 47 inches tall when mature and produces flower clusters above leaves. It is considered invasive in the Great Lakes region, Pacific Northwest, and California in the United States.

Caring for Poa

Poa can be planted via seed or sod, and should be situated in full sun to partial shade. These grasses prefer cooler, moist environments and will struggle or die off in intense, hot full sun. Afternoon shade is recommended for best results. Ensure that soil is well-draining, moderately fertile, and has a pH of between 5.5 and 7.0 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these grasses need regular water to remain green and prevent dieback.

Fertilize a few times a year with a decomposed compost that is fine in texture and well-rotted. Apply a 1/4 inch layer over the area and gently work it in to the soil using a rake or brush. Water it in thoroughly after application, and then continue care as usual. Poa grasses can be left to grow naturally, or they can be mowed as a lawn. They are best when mowed to between 1 and 2 inches tall, but can also be used as turf mowed to 0.5 inches or less. Unmowed, they typically reach 2-3 feet tall and can be pruned to remove dead and damaged foliage to encourage new growth to emerge. Late winter or early springtime is the best time of the year to complete this type of pruning. Most species will die back in summer in many regions, as they are cool-season grasses and cannot handle high heat. Perennial species are long-lived, and are able to survive for many years in the garden before fading. They will naturally re-seed and spread via underground rhizome roots, providing new plants for the landscape indefinitely.

Propagation

Poa, or Bluegrass, is best propagated by division or seed. To propagate your grass, follow the instructions below:

Propagating Poa by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, and a spray bottle. If you don't have any potting medium on hand, you can make some. A good potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded, and are typically held above the foliage on thin stems. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Get your container prepared. Water the seed tray or pot filled with soil, and ensure that good drainage is occurring. Place the seeds about a quarter inch under the soil surface. Cover them with soil and water with the spray bottle. Place the tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7 and 30 days from sowing.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Poa by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in early spring or fall. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
Separate the removed patch of grass into sections using a sharp, clean knife or trowel. Ensure that each division has a healthy root system and a few shoots. Any dried out areas with dead roots can be tossed in the compost.
Prepare your pot(s) or new planting site(s) with well-draining soil and compost and rake it in. Water thoroughly, and then place divisions on top.
Keep soil consistently moist as the newly-planted divisions establish strong root systems in their new home. Provide regular waterings, especially during dry spells. It typically takes between 1 and 2 weeks for these grasses to develop their initial shallow root systems, and up to 30-45 days for their deeper roots to form.

Problems and Pests

Certain species of Poa are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Poa grasses are susceptible to developing issues with the following pests and diseases in the landscape: