Andropogon

( an - droh - POH - gon )

At-A-Glance Information

Also called Big Bluestem, Beardgrass or Turkeyfoot, this genus of perennial grasses includes species which need full sun or light shade, and little to regular water. to perform well in the landscape. This classic prairie grass can reach 8 feet tall, but in drier climates is more likely to reach 3-5 feet at maximum. Thin blades are blue-green in summer (hence the common name Bluegrass) and turn bronze-red or copper in fall when temperatures drop. Flowers aren't showy, but they are interesting. They form on spikes that are purple-tinted and are arranged in sets of three or more. Bluestem makes an effective screening plant when massed and given regular irrigation. They can grow singly in mixed border plantings as well, or be used for slope and erosion control in the garden. Take care when planting these grasses in the landscape, as some species are toxic to humans or pets if ingested.

Andropogon Species and Varietals

The genus Andropogon is a member of the plant family Poaceae and includes over 100 species. These grasses grow well in USDA zones 3-9. For more specific growing information, see the species descriptions below. To find your zone, click here: Zone Map.

Andropogon gayanus (Gamba Grass, Rhodesian Blue Grass, Tambuki Grass)
These grasses are native to tropical and subtropical savannas in Africa, and can reach 13 feet tall and 2.3 feet wide. They form dense patches of foliage and tend to out-compete native grasses. They are problematic in fire-prone areas. It is considered an invasive weed in some areas of the globe, including Australia.

Andropogon gerardi (Big Bluestem, Tall Bluestem, Bluejoint, Turkeyfoot)
These plants are tolerant of a wide variety of soil conditions and growing climates, and form a very strong sod. Plants typically reach between 3.3 and 10 feet tall when mature. These grasses bloom in summertime, and seed in fall. Popular cultivars include 'Bison' (with increased cold tolerance), 'Blackhawks' (with dark reddish-purple toned foliage), 'El Dorado', 'Earl', 'Kaw', 'Niagara', and 'Roundtree'.

Andropogon virginicus (Broomsedge Bluestem, Yellowsedge Bluestem)
These plants are native to the eastern United States, and have naturalized in other areas, including California and Hawai'i, where it is considered a weed. They are sometimes grown as ornamental grasses, and have a good fire tolerance. Plants typically reach a bit over three feet tall when mature, and form narrow clumps of stems. They seed prolifically.

Caring for Andropogon

Grow Andropogon, or Bluestem, in an area of the garden that receives full sun to partial shade. Ensure that soil is well-draining, moderately fertile, and has a pH of between 5.5 and 7.0 (slightly acidic to neutral). They can grow well in less-than-ideal soil conditions and can tolerate poor quality and shallow soils, but do not like to have their roots compacted or sit in soggy soil. 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 are valued for their drought tolerance, getting by on rainwater for much of the year with a few irrigations during extended periods of drought.

Fertilizing Andropogon plants is optional; 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. Fertilizing really only needs to be done in situations where Bluegrass is grown in particularly poor soils. Prune to remove dead, damaged, or diseased foliage at any time during the active growing season in spring and summertime. Shaggy, older growth can be pruned back in springtime using sharp, clean garden shears. If growing Bluestem grasses in a cramped garden border or container, they will need to be divided every few years to ensure ongoing health. For instructions on how to successfully divide Bluestem grasses, see the propagation section below.

Propagation

Andropogon, or Bluestem, is best propagated by division or seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant, especially if you are propagating a hybrid cultivar. To propagate your Bluestem, follow the instructions below:

Propagating Andropogon 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. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. 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 your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your 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 2-6 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
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 Andropogon by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in early spring or fall, and should only be attempted with established plants To propagate Andropogon 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.

Problems and Pests

Bluestem grasses are considered resilient in the landscape, and do not suffer from any serious pest or disease problems. For information on commonly-encountered pests and diseases in the home garden, see the following pages:

Pests & Pest Management

Plant Issues