Karl Foerster Grass: Real Size, Zones, Care and Cultivars Compared

Key takeaways

• In Chicago Botanic Garden’s zone 5b trial (minimum four years), ‘Karl Foerster’ measured 66 in tall and 40 in wide and earned its top four-star rating (CBG, Fine Gardening, Oct. 2023).
• Zone listings run from 3 (UW-Madison Extension) to 11 (Proven Winners); the North Carolina grower Hoffman Nursery lists 4 to 7, and Walters Gardens lists 4 to 8.
• The hybrid “rarely sets fertile seed” (CBG), and Missouri Botanical Garden calls its seed sterile, so it does not reseed; Korean feather reed grass does, and CBG put it on its removal list.
• Cut it to about 6 inches in late winter, before new shoots (Purdue Extension); published advice ranges from cutting to the ground (MoBot) to leaving one-third of the plant (NC State).
• Rust is the recurring disease: the PNW Plant Disease Management Handbook (rev. March 2026) lists three Puccinia species on ‘Karl Foerster’ in Oregon and Washington.
• Listed prices on Oct. 29, 2026 ran from $13.85 for a 3.5 in pot to $83 for a 1.6 gal Monrovia plant; a 20 ft row at 24 in spacing takes 10 plants.

Attribute	Value	Source
Botanical name	Calamagrostis x acutiflora ‘Karl Foerster’, a hybrid of C. arundinacea and C. epigejos	MoBot
Growth cycle	Cool-season: grows most in spring below 75 °F, holds color through summer	NC State
Bloom	Early to mid summer (early June in North Carolina); plumes about 11 in long	NC State; CBG trial
Height in bloom	66 in measured; 5 to 6 ft published	CBG; UW-Madison
Width	40 in measured; 2 to 3 ft published	CBG; Proven Winners
USDA zones	4 to 7 reliable; listings run from 3 to 11	Hoffman; New Moon
Spacing	24 to 36 in on center	Proven Winners; Great Garden Plants
Annual cutback	To about 6 in, late winter or very early spring	UW-Madison; Purdue
Award	2001 Perennial Plant of the Year, the first ornamental grass to win	Perennial Plant Association; Hoffman
Price per plant	$13.85 (3.5 in pot) to $83 (1.6 gal), listed prices	7 sellers, checked Oct. 29, 2026

How big does Karl Foerster grass grow?

Karl Foerster grass grows a 2 to 3 ft clump of leaves with flower stalks to 5 or 6 ft. The best measured figure comes from Chicago Botanic Garden, where plants grown at least four years in zone 5b averaged 66 inches tall and 40 inches wide, wider than the 1 to 2 ft many plant tags print (Hawke, CBG, 2023).

Width is the number to plan around. NC State’s Plant Toolbox lists 1 to 1.5 ft and Walters Gardens 2 ft, but CBG’s trial plants reached 40 inches on alkaline clay loam with minimal care, closer to the 2 to 3 ft spread Proven Winners prints. CBG’s Richard Hawke writes that the flower stalks make up about two-thirds of the plant’s height.

Source	Leaf clump	Height in bloom	Width	Type of figure
Chicago Botanic Garden trial	not reported	66 in	40 in	Measured, zone 5b, 4+ years
UW-Madison Extension	2 to 3 ft	5 to 6 ft	under 2 ft	Published range
Purdue Extension	2 to 3 ft	to 5 ft	not given	Published range
Missouri Botanical Garden	to 3 ft	3 to 5 ft	1.5 to 2.5 ft	Published range
NC State Extension	not given	3 to 5 ft	1 to 1.5 ft	Published range
University of Minnesota Extension	not given	5 ft	2 ft	Published figure
Hoffman Nursery	2 ft	6 ft	not given	Grower spec
Monrovia	2 ft	6 ft	2 ft	Grower spec
Walters Gardens	not given	5 ft	2 ft	Grower spec
Proven Winners	not given	4 to 6 ft	2 to 3 ft	Brand spec

Height depends on soil fertility, not just zone. UW-Madison says fertilizer may be needed for maximum height in infertile soil, and New Moon Nursery says low fertility gives shorter plants. Run a soil test before feeding: CBG’s grass evaluation warns that fertilizing grasses makes them lush and floppy.

What zones does Karl Foerster grass grow in?

Most lists put Karl Foerster grass in USDA zones 4 or 5 through 8 or 9, where average annual extreme lows run from minus 30 °F to 30 °F (USDA Plant Hardiness Zone Map). Two wholesale growers, Hoffman Nursery and New Moon Nursery, call it reliable only in zones 4 to 7; New Moon says plants survive in 8 and 9 but need cold winters.

1. UW-Madison Extension3
2. Hoffman Nursery (N.C.)4
3. New Moon Nursery (N.J.)4
4. University of Minnesota Extension4
5. Walters Gardens (Mich.)4
6. Great Garden Plants4
7. Monrovia4
8. Missouri Botanical Garden5
9. NC State Extension5
10. High Country Gardens5
11. Nature Hills Nursery5
12. Proven Winners5

Source: Plant pages of the 12 sources named, accessed October 2026; zone definitions from USDA ARS 2023 map Same numbers as the zone table below the chart. Zone 4 is minus 30 to minus 20 °F; zone 11 is 40 to 50 °F.

Show the numbers

	Coldest zone listed	Warmest zone listed
UW-Madison Extension	3	9
Hoffman Nursery (N.C.)	4	7
New Moon Nursery (N.J.)	4	7
University of Minnesota Extension	4	8
Walters Gardens (Mich.)	4	8
Great Garden Plants	4	8
Monrovia	4	9
Missouri Botanical Garden	5	9
NC State Extension	5	9
High Country Gardens	5	8
Nature Hills Nursery	5	9
Proven Winners	5	11

Source	Coldest zone	Warmest zone	Type of source
UW-Madison Extension	3	9	University extension
Hoffman Nursery (N.C.)	4	7	Wholesale grower
New Moon Nursery (N.J.)	4	7	Wholesale grower; says plants survive in 8 and 9 but are not reliable south of 7
University of Minnesota Extension	4	8	University extension
Walters Gardens (Mich.)	4	8	Wholesale propagator; carries the Proven Winners perennial line
Great Garden Plants	4	8	Retail nursery
Monrovia	4	9	Grower and retailer
Missouri Botanical Garden	5	9	Botanical garden
NC State Extension	5	9	University extension
High Country Gardens	5	8	Retail nursery
Nature Hills Nursery	5	9	Retail nursery
Proven Winners	5	11	Consumer plant brand

The outliers sit at both ends. Proven Winners’ consumer page lists zones 5 to 11, while Walters Gardens, the wholesale nursery whose catalog carries the Proven Winners perennial line, lists 4 to 8 for the same plant. Zone 11 means winter lows of 40 to 50 °F, and NC State says the grass suffers in hot, humid or wet summers. Zone 3 (minus 40 to minus 30 °F) appears only on the UW-Madison page.

Our read: treat zones 4 to 7 as the reliable band, plant zone 8 with afternoon shade, and trial two or three plants before committing a full row in zone 3. Six of the 12 sources list zone 4 as the coldest, including University of Minnesota Extension; five list zone 5.

Where is the best place to plant Karl Foerster grass?

Plant Karl Foerster grass in full sun, 6 or more hours a day, in moist soil that drains; it also takes heavy clay, wet spots and dry spells once established. Missouri Botanical Garden lists it for rain gardens and as tolerant of wet soil, erosion, black walnut and urban conditions. In shade it flowers less and its foliage flops.

Site factor	What the sources say	Source
Sun	Full sun (6+ hours); in part sun (2 to 6 hours) expect fewer flowers and floppier foliage	NC State; MoBot
Hot-summer climates	Afternoon shade helps in places like St. Louis and the South	MoBot; CBG
Soil texture	Does well in heavy clay, unlike many ornamental grasses; tolerates compacted soil	UW-Madison; Hoffman
Moisture	Medium to wet; relatively drought tolerant once established	MoBot; UW-Madison
Soil pH	Acid (below 6.0) through alkaline (above 8.0)	NC State
Other tolerances	Black walnut, erosion, urban conditions; salt tolerant per Walters	MoBot; Walters Gardens
Animals	Highly resistant to deer and rabbit grazing; voles and gophers can feed on grass roots	NC State; CBG Issue 43
Containers	Works in patio pots and as a vertical accent in narrow spaces	UW-Madison; MoBot

Plant in fall if you can. The culture notes in CBG’s 2023 reed grass report call fall the best planting time and say early spring usually works too; loosen the roots of root-bound nursery plants at planting. Monrovia says to water deeply and regularly through the first growing season, then water when the top 2 inches of soil are dry.

For a long row, a single drip line with an emitter at each plant meets that first-season schedule without wetting the leaves, which matters because CBG advises minimizing overhead irrigation to keep grass diseases such as rust down; our drip irrigation setup guide covers emitter sizing. Mulch the bed 2 to 3 inches deep, the band extension services give for beds, using our mulch calculator for the order.

How far apart should you plant Karl Foerster grass, and what will a row cost?

Space Karl Foerster grass 24 to 36 inches apart, the range Proven Winners and Great Garden Plants print, or about 17 inches for a dense mass: High Country Gardens says a flat of 9 plants covers 18 sq ft, or 2 sq ft per plant. A 20 ft row at 24 inches takes 10 plants.

The arithmetic: plants in a row equal row length in inches divided by spacing, rounded up, with the end plants set half a spacing in from each end. For a bed on a square grid, plants per 100 sq ft equal 14,400 divided by the spacing squared. The cost columns multiply the 20 ft count by the price ranges in the price table below.

Spacing on center	Plants per 20 ft row	Plants per 100 sq ft	20 ft row, 3.5 in pot to quart ($10.38 to $19.99)	20 ft row, 1 gallon ($15.95 to $29.95)
17 in (High Country Gardens density (9 plants per 18 sq ft))	240 ÷ 17 = 14.1, so 15	14,400 ÷ 289 = 49.8, so 50	$155.70 to $299.85	$239.25 to $449.25
18 in (dense screen)	240 ÷ 18 = 13.3, so 14	14,400 ÷ 324 = 44.4, so 45	$145.32 to $279.86	$223.30 to $419.30
24 in (Proven Winners and Great Garden Plants low end)	240 ÷ 24 = 10.0, so 10	14,400 ÷ 576 = 25.0, so 25	$103.80 to $199.90	$159.50 to $299.50
30 in (middle of the printed range)	240 ÷ 30 = 8.0, so 8	14,400 ÷ 900 = 16.0, so 16	$83.04 to $159.92	$127.60 to $239.60
36 in (Proven Winners and Great Garden Plants high end)	240 ÷ 36 = 6.7, so 7	14,400 ÷ 1,296 = 11.1, so 12	$72.66 to $139.93	$111.65 to $209.65

Row length (linear ft)Pot size and price per plant (price table, Oct. 29, 2026)3.5 in pot to 1 quart, mail order ($10.38 to $19.99)1 gallon ($15.95 to $29.95)Monrovia #1 to #2, home delivery ($46 to $83)Spacing on center24 inches (low end of the printed range)18 inches (dense screen)30 inches36 inches (high end of the printed range)RowsSingle rowDouble staggered row

Plants needed

10

Estimated plant cost, before tax and shipping$105 to $200

Plants = row length in inches ÷ spacing per row, rounded up. Cost uses the unrounded count. Spacing from Proven Winners and Great Garden Plants; prices checked Oct. 29, 2026.

A tight row works as a seasonal screen, not a year-round one. Hawke writes that feather reed grass planted tightly makes “an excellent screen” for seasonal privacy, but the stalks come down at the late-winter cutback and regrow from 6 inches. At CBG’s measured 40-inch width, clumps on 24-inch centers overlap; at 36 inches they stay separate. For a screen that stays up in winter, compare the evergreens in our fast-growing trees ranking.

1. American Meadows, 3.5 in pot$13.85
2. High Country Gardens, 5 in deep pot$14.99
3. Great Garden Plants, 1 quart$15.99
4. Plants Express (Calif.), 1 gallon$15.95
5. Nature Hills Nursery, 1 quart$19.99
6. Garden Goods Direct, 1 gallon$29.95
7. Monrovia, #1 (0.75 gal)$46
8. Monrovia, #2 (1.6 gal)$83

Source: Seller product pages, checked Oct. 29, 2026 Same numbers as the price table below. List prices before sale, volume discount, tax and shipping.

Show the numbers

	Listed price
American Meadows, 3.5 in pot	$13.85
High Country Gardens, 5 in deep pot	$14.99
Great Garden Plants, 1 quart	$15.99
Plants Express (Calif.), 1 gallon	$15.95
Nature Hills Nursery, 1 quart	$19.99
Garden Goods Direct, 1 gallon	$29.95
Monrovia, #1 (0.75 gal)	$46
Monrovia, #2 (1.6 gal)	$83

Seller	Pot size	Listed price	Sale or volume price	Source
American Meadows	3.5 in pot	$13.85	$10.38 on sale; $9.35 each for 36; out of stock	product page
High Country Gardens	5 in deep pot	$14.99	$10.49 on sale; $9.45 each for 36	product page
Great Garden Plants	1 quart	$15.99	$2.00 off each at 24 or more	product page
Plants Express (Calif.)	1 gallon	$15.95	5 gallon also listed	product page
Nature Hills Nursery	1 quart	$19.99	#1 container also listed	product page
Garden Goods Direct	1 gallon	$29.95	shown as sale price during a 20% off sitewide sale	product page
Monrovia	#1 (0.75 gal)	$46.00	home delivery price	product page
Monrovia	#2 (1.6 gal)	$83.00	home delivery price	product page

Pot size drives the price more than the seller does. Small mail-order pots ran $13.85 to $19.99 at list, 1-gallon plants $15.95 to $29.95, and Monrovia’s home-delivered #1 and #2 containers $46 and $83. Installed by a crew, our landscaping cost model puts a 1-gallon perennial at about $14 to $34 including labor.

When should you cut back Karl Foerster grass, and how short?

Cut Karl Foerster grass back once a year in late winter or very early spring, before new shoots appear, to about 6 inches (UW-Madison Extension; Purdue). It is a cool-season grass that starts growing early, so a late cut clips the new leaves. Leaving it standing through winter keeps the upright plumes for winter interest.

Source	Cut to	When
Missouri Botanical Garden	The ground	Late winter, just before new spring shoots
Monrovia	The ground	Late winter, just before new shoots
New Moon Nursery	The ground	Late winter, before new growth
Great Garden Plants	The ground	Late winter, just before new shoots
High Country Gardens	3 in	Late spring
CBG Issue 43 (all grasses)	About 4 in	Late fall to early winter, or late winter to early spring
CBG, Hawke (reed grasses)	6 in or less	By late winter
UW-Madison Extension	About 6 in	Late winter or very early spring
Purdue Extension	About 6 in	Late winter or early spring
NC State Extension	Leave about one-third of the plant	Early spring; warns harsh cutting can be detrimental

Nine of the 10 sources cut to 6 inches or lower, and at least seven time the cut for late winter. NC State’s one-third is the outlier; High Country Gardens’ late-spring date runs late for a grass that NC State says grows most while temperatures stay below 75 °F. Our recommendation is 3 to 6 inches in late winter.

1. Wait for late winter and check the base of the clump; cut before the new shoots emerge (MoBot).
2. Put on heavy gloves and long sleeves: CBG warns that grass leaf margins can be razor-sharp and irritate skin.
3. Cut the clump to 3 to 6 inches with hand pruners or hedge shears, the tools CBG lists for a clump this size.
4. Rake out the cut stems. If the clump had rust last season, bin them rather than compost them, as a Minnesota Extension Master Gardener advised in an Ask Extension answer (2016).
5. Mark your calendar for division: CBG suggests every 5 to 7 years for grasses with hollow centers, and Great Garden Plants every 4 to 5 years.

Does Karl Foerster grass spread or reseed?

Karl Foerster grass does not reseed in the garden. Missouri Botanical Garden, UW-Madison and NC State call its seed sterile, and CBG’s Richard Hawke says the hybrid “rarely sets fertile seed.” Clumps widen slowly: NC State says it spreads slowly by rhizomes, and CBG measured 40-inch clumps after four years. Korean feather reed grass, by contrast, can self-sow.

Hawke notes that both parents, C. arundinacea and C. epigejos, are prolific self-sowers; the hybrid’s seed sterility is why University of Illinois Extension (May 2026) says “thus far it has not exhibited signs of invasiveness.” The University of Arizona Campus Arboretum record lists it as benign and non-spreading.

Buy plants or divide a clump rather than sowing seed; the University of Arizona record says the hybrid cannot be propagated by seed. Divide every 4 to 7 years, in fall or spring (UW-Madison):

1. Divide in early spring before new leaves emerge, or in fall; if the clump is already growing, cut it back by one-third first (CBG Issue 43).
2. Split the crown with a sharpened spade or axe, and replant healthy divisions right away (CBG Issue 43).
3. Set each division at its old depth and water it in on the first-season schedule above.
4. Expect large fall divisions to flower the next spring and small ones to need a second growing season (UW-Madison).

What are the common problems with Karl Foerster grass?

Karl Foerster grass has one recurring disease, rust, and three cultural problems: flopping in shade, short growth in poor soil and a dying center in old clumps. The Pacific Northwest Plant Disease Management Handbook (rev. March 2026) records rust on ‘Karl Foerster’ in spring in western Oregon, caused by fungi in the genus Puccinia.

Problem	What triggers it	What to do	Source
Rust: Puccinia coronata (Ore., Wash.), P. pygmaea (Ore.), P. rhamni (Wash.)	Prolonged rain; hot, humid or wet summers; shade and overhead watering	Full sun, well-drained soil, water at the base; cut and bin infected foliage	PNW Handbook; NC State; CBG Issue 43
Flopping stems	Shade; heavy rain or wind	Move to full sun; rain-flattened stems return upright once dry	MoBot; UW-Madison
Short plants	Low soil fertility	Test soil first; feed lightly only if low, since feeding grasses causes flop	UW-Madison; New Moon; CBG Issue 43
Dead center	Old, undivided clumps	Divide every 4 to 7 years	CBG 2023; Great Garden Plants
Weak growth in the South	Zone 8 to 9 heat and humidity	Afternoon shade, or a warm-season grass	NC State; New Moon; CBG 2023
Nursery pests	Aphids, leaf spot, spider mites, tar spot listed for container production	Inspect plants at purchase	Hoffman Nursery

Shade and wet weather raise the rust risk. CBG’s 2018 grass evaluation recorded severe rust on ‘Overdam’ grown in a shaded bed from 2009 to 2012, and wholesale grower Hoffman Nursery calls ‘Karl Foerster’ “very susceptible to rust” in container production. In the 2016 Minnesota case, the volunteer said late-season rust after heavy rain needs no treatment and the clump usually regrows clean.

This page is general information. If you use a fungicide on ornamental grass rust, the product label is the law: use only a product whose label lists the plant and the disease, at the label rate.

Karl Foerster vs Overdam, Avalanche, Eldorado and Korean feather reed grass: which should you pick?

Pick ‘Karl Foerster’ for height and the best trial record, and ‘Avalanche’ or ‘Eldorado’ for striped leaves on the same upright form. In Chicago Botanic Garden’s trials of 11 reed grasses since 2018, ‘Karl Foerster’, ‘Avalanche’, ‘Eldorado’, ‘Hello Spring’ and ‘Cheju-do’ earned four stars; ‘Overdam’, ‘Lightning Strike’ and Korean feather reed grass earned three (CBG, 2023).

1. 'Karl Foerster'66
2. 'Eldorado'60
3. 'Lightning Strike'60
4. 'Hello Spring'54
5. Korean (C. brachytricha)53
6. 'Overdam'52
7. C. epigejos (a parent)52
8. 'Avalanche'50
9. 'Cheju-do'33

Source: Chicago Botanic Garden comparative trials since 2018, zone 5b (Hawke, Fine Gardening, Oct. 2023) Same numbers as the cultivar table below. Minimum four years in full sun on alkaline clay loam.

Show the numbers

	Height	Width
'Karl Foerster'	66	40
'Eldorado'	60	30
'Lightning Strike'	60	40
'Hello Spring'	54	36
Korean (C. brachytricha)	53	46
'Overdam'	52	32
C. epigejos (a parent)	52	24
'Avalanche'	50	30
'Cheju-do'	33	58

Plant	CBG rating	Measured height x width	Leaves	Flower color and plume length	Other source notes
‘Karl Foerster’	4 of 4 (excellent)	66 x 40 in	bright green	purple-pink, 11 in	First ornamental grass named Perennial Plant of the Year, 2001 (Hoffman)
‘Eldorado’	4 of 4 (excellent)	60 x 30 in	golden center stripe, green edges	pale purple, 10 in	Same vertical habit as ‘Karl Foerster’ (CBG)
‘Avalanche’	4 of 4 (excellent)	50 x 30 in	white center stripe, green edges	light purple, 8 in	Shortest C. x acutiflora cultivar in the trial; MoBot lists 2 to 4 ft (MoBot)
‘Hello Spring’	4 of 4 (excellent)	54 x 36 in	wide creamy white edges	pink, 11 in	Plumes opened on the first day of summer; bulked up faster than ‘Overdam’ (CBG)
‘Cheju-do’	4 of 4 (excellent)	33 x 58 in	green with silvery hairs	pink and green, 6 in	Mounded, not upright; zones 5 to 8 (CBG)
‘Lightning Strike’	3 of 4 (good)	60 x 40 in	wide creamy white center stripe	purple, 9 in	Larger than ‘Avalanche’ (CBG)
‘Overdam’	3 of 4 (good)	52 x 32 in	creamy white edges, green centers	pink, 9 in	48 x 38 in and severe rust in CBG’s shade bed, 2009 to 2012 (CBG Issue 43)
Korean feather reed grass (C. brachytricha)	3 of 4 (good)	53 x 46 in	lustrous green	purple and green, 10 in; blooms Sept. to Nov. (MoBot)	Can self-sow; on CBG’s removal list; grows in light to medium shade (CBG)
C. epigejos (a parent species)	2 of 4 (fair)	52 x 24 in	medium green	purple-green, 11 in	Prolific self-sower (CBG)
‘Stricta’	Not rated	1 to 2 ft taller than ‘Karl Foerster’ (NC State)	green	Flowers about 2 weeks later (NC State)	Often mislabeled as ‘Karl Foerster’ in nurseries (NC State)

Korean feather reed grass is the one to weigh carefully. It blooms September to November rather than June and grows in light to medium shade, but CBG’s report says reports of self-sowing range from minimal to aggressive and the garden removed it; Plant Select also notes it may reseed. Pull seedlings, especially near water.

The ‘Stricta’ label adds confusion. NC State treats ‘Stricta’ as a separate clone that grows 1 to 2 ft taller and flowers about 2 weeks later, while Hawke writes that Karl Foerster originally called his own selection ‘Stricta’ before it was renamed in his honor. Buy from a grower that labels the plant Calamagrostis x acutiflora ‘Karl Foerster’.

What plants go well with Karl Foerster grass?

Purple coneflower and Russian sage are the companions named most often: each appears in 3 of the 5 grower and garden sources we compiled. Late-summer bloomers suit the grass because its plumes turn buff by late summer (NC State); UW-Madison Extension names Coreopsis, Echinacea, Liatris and Rudbeckia.

Companion plant	Named by	Sources naming it
Purple coneflower (Echinacea purpurea)	UW-Madison; Chicago Botanic Garden blog; New Moon Nursery	3
Russian sage (Perovskia atriplicifolia)	CBG blog; Monrovia; High Country Gardens	3
Black-eyed Susan (Rudbeckia, incl. R. fulgida var. fulgida)	UW-Madison; New Moon	2
Aster (incl. ‘Raydon’s Favorite’)	Monrovia; New Moon	2
Coreopsis; Liatris	UW-Madison	1 each
Leichtlin’s lily (Lilium leichtlinii)	CBG blog	1
Arkansas blue star (Amsonia hubrichtii)	New Moon	1
Spirea, potentilla, shrub rose	Monrovia	1 each
Artemisia ‘Powis Castle’	High Country Gardens	1

Mix rather than line up. After trialing 11 reed grasses, Hawke calls a stark line of this columnar grass “soulless after the thousandth encounter” and suggests small to large masses, or pairing with looser perennials or bushy shrubs. CBG’s Evening Island, designed by Oehme, van Sweden and Associates, uses ‘Karl Foerster’ as a cornerstone grass, and the garden suggests breaking its sweeps with Russian sage, purple coneflower or Leichtlin’s lily (CBG blog).

Is Karl Foerster grass right for your yard?

Karl Foerster grass fits a sunny site in zones 4 to 7 that needs a narrow, upright accent or a seasonal screen, wet clay included. Skip it, or pick another grass, where shade is heavy, summers are hot and humid, or the plan calls for natives: Illinois Extension names junegrass, little bluestem and sideoats grama.

If your situation is	Do this	Why (source)
Zone 4 to 7, 6+ hours of sun	Plant ‘Karl Foerster’ 24 to 36 in apart	Four-star CBG rating; zones 4 to 7 per Hoffman and New Moon
Zone 3 (minus 40 to minus 30 °F)	Trial 2 or 3 plants before a full row	Only UW-Madison lists zone 3; the other 11 sources stop at zone 4 or 5
Zone 8 or 9 with hot, humid summers	Give afternoon shade, or plant a warm-season grass such as pink muhly	NC State: suffers in hot, humid summers; New Moon: not reliable south of zone 7
Under 6 hours of sun	Expect flop; consider Korean feather reed grass and pull its seedlings	MoBot; CBG removal list for Korean
Wet clay, rain garden or pond edge	‘Karl Foerster’ suits it	MoBot lists wet soil and rain gardens; UW-Madison notes clay
You want striped leaves	‘Avalanche’ (50 in) or ‘Eldorado’ (60 in) over ‘Overdam’	Four stars vs three; ‘Overdam’ had severe rust in shade (CBG)
Native plants required	Little bluestem (zones 3 to 9, 2 to 4 ft) or junegrass; ‘Thin Man’ Indiangrass in the dry West	MoBot; Illinois Extension; Plant Select
You need a winter screen	Use evergreens; this grass is cut to 6 in each late winter	UW-Madison; Hawke calls it a seasonal screen
Replacing pampas grass in the Northwest	‘Karl Foerster’ is a named non-invasive stand-in	Washington agencies, in our pampas grass guide

1. 1Does the spot get less than 6 hours of direct sun?

   YesExpect fewer plumes and flopping (MoBot). For light shade, Korean feather reed grass grows there but can self-sow (CBG).

   NoGo to the next question

2. 2Is your winter colder than zone 4 (below minus 30 °F)?

   YesTrial 2 or 3 plants first; only UW-Madison lists zone 3.

   NoGo to the next question

3. 3Are you in zone 8 or warmer with hot, humid summers?

   YesGive afternoon shade and watch for rust, or choose a warm-season grass such as pink muhly (NC State; New Moon).

   NoGo to the next question

4. 4Does the plan require native plants?

   YesUse little bluestem or junegrass; in the dry West, 'Thin Man' Indiangrass (Illinois Extension; Plant Select).

   NoGo to the next question

5. 5Do you want striped leaves?

   YesChoose 'Avalanche' or 'Eldorado', both four-star in CBG's trial.

   NoPlant 'Karl Foerster' 24 to 36 inches apart (17 to 18 inches for a dense screen) and cut it to about 6 inches each late winter.

Source: Decision table above: CBG 2023, MoBot, NC State, New Moon, Illinois Extension, Plant Select

For more cool- and warm-season grass profiles, browse our Turf and Trees hub.

Document type	Count	Examples
University extension plant records	7	UW-Madison, NC State (3 pages), Minnesota, Purdue, Illinois
Botanical garden records and trials	6	Missouri Botanical Garden (5 records), Chicago Botanic Garden trials 2018 and 2023
Disease handbook and extension Q&A	2	PNW Plant Disease Management Handbook (rev. March 2026); Ask Extension #356470
Grower spec sheets	6	Hoffman, Walters, New Moon, Monrovia, Proven Winners, Plant Select
Retail price listings	7	American Meadows, High Country Gardens, Great Garden Plants, Nature Hills, Plants Express, Garden Goods Direct, Monrovia
Reference maps, awards and records	5	USDA zone map, Perennial Plant Association, University of Arizona arboretum, CBG blog, Plant Select brachytricha page