Download Gardening With Ornamental Grasses Presented by Michelle Cox Master Gardener

Gardening With
Ornamental Grasses
Presented by Michelle Cox
Master Gardener
University of Illinois Extension
Getting to Know Grasses
• Cool Season Grasses
• Warm Season Grass
• Main growth when its cool
and flower in late spring to
early summer
• Put on their main growth
when its warm and flower
midsummer into fall
• Retain some winter
character
• They are the stars of the
late summer garden
• Go dormant during warm
weather
• Go dormant during cool
weather
Getting to Know Grasses
• Running Type
• Clump Formers
• Spread by rhizomes
(specialized underground
stems)
• Usually not invasive but have a
defined habit
• Use caution when planting this
type of grass as it can take
over
• They are excellent however for
erosion control
• Examples: Ribbon grass and
cord grass
• A few of these grasses can be
invasive by seed Example:
some Miscanthus and some
Pennisetum
• Can be used in combination
with annuals and perennials
with little fear of them taking
over
Tufted Grass: Have spiky
upright leaves that arise
from the center point.
Example: Fescue; ‘Elijah Blue’
Mounded Grass: Have gracefully
curved foliage that radiates out
from a central point.
Example: Fountain Grass; ‘Red Head’
Upright Grass: Have strong vertical
leaves, usually growing in columnar
clumps.
Example: Switchgrass; ‘Northwind’
Combination Shapes: There are a number of
grasses that have combination shapes. There
foliage might be mounded, for instance, but
their flower stems are upright.
Combination Shapes: On the other hand it
might have a combination of upright
stems and arching foliage, which produces
a fountain like effect.
Example: Feather Reed Grass ‘Karl Forester’
Example: Maiden Grass ‘Graziella’
The Light Fantastic: Most grasses need full
sunlight, a few will do well in partial shade
•
Sidelighting
•
Backlighting
•
Creates dramatic contrasts between
areas of brightness and shadow,
delineating the distinctive shapes and
textures of leaves, flowers, and seed
heads
•
When the grass is directly behind an
ornamental grass, the plant is thrown
into silhouette, revealing each amazing
detail and the plant seems to glow
from within
•
It’s an excellent way to highlight grasses
with delicate blooms that tend to get
lost against a busy background of
colorful leaves and flowers
•
In some cases the light may shine
through the leaves, creating an effect
much like that of light pouring through
a stained glass window
•
Simply site the grass against a dark
background in an area where they will
be lit by the sunrise or the sunset, and
they will positively shimmer.
•
Installing landscape lighting can create
similar light effects in the evening
Culture of Ornamental Grasses
•
Plant in the spring so they have time to get established. Late
summer/early fall planting is also acceptable if you do it early enough.
•
Keep in mind that width is usually equal to the height, and that many
grasses take up a lot of space. It takes about 3 years for most grasses to
mature to their normal height and width.
•
No extra fertilizer is needed other than good soil. If fertilizer is desired,
apply ½ to 1 pound of a 5-10-5 per 100 Sq. Ft. in early spring as
growth begins. Avoid fertilizing too much or too often as this results in
weak growth and falling over grasses.
•
The only need for additional water is during establishment of new plants.
Once they are established, most of them, especially warm-season types,
are drought tolerant.
Culture of Ornamental Grasses
•
Ornamental grass benefit from a light mulch 2-3” placed around the
plant. Try not to mulch over the crown. Mulching will help control
weeds and conserve moisture
•
Most grasses are cut back in the fall or in the spring before new growth
begins. Some grasses have raised crowns, don’t cut into the crowns
•
As grasses grow they spread from the center. Over time the center
portion can become crowded and weak. Division is the most common
way to keep clumps healthy. Divide in the spring before growth starts.
Usually every 3-4 years is sufficient
•
Dig up the entire clump, once it is lifted divide into section. If the center
is dead, toss it. Replant the divisions, backfill with soil, and water
thoroughly.
Cool Season:
Feather Reed Grasses
Karl Forester: Clump forming.
Adds a nice vertical accent to
the garden.
24-36” high
Overdam: Clumps of
variegated foliage and a slight
more compact form.
24-36” high
Eldorado: Clumps of narrow
green leaves with a bright gold
midrib. Feathery plumes
48-72” high
Cool Season: Blue Fescue
Elijah Blue: Here it is planted with some
groundcover sedum ‘dragon’s blood’ as the
border of a landscaped bed. Small neat blue
mounds will persist late into the winter if it
is not packed down by snow and ice. Will
tolerate dry poor soil, but not heavy moist
soil.
10-20” high
Cool Season: Hakone Grass
Aureola: Nice dwarf size grass
with slender stems that hold
bright yellow foliage with thin
green stripes. It will be happy
in shade and organic, well
drained soil.
18-24” high
Cool Season: Blue Oat Grass
Sapphire: Clump forming with a great blue
foliage. Has an attractive upright, arching
somewhat stiff habit. Wonderful planted in
masse or as a single specimen. Needs full sun
for good growth and color.
Clump can reach 2’ with flower spikes
growing out of the clump 2-3’ higher
Warm Season: Miscanthus;
Maiden Grasses
Gracillimus: Fine textured with
a pleasing symmetrical, arching
shape. Bronze-red flowers
appear in late September.
5-6’ high with flowers
Graziella: Finely textured vase
shaped grass that produces
silver-white flowers in August
that reach 2’ above the foliage.
Fall color is a coppery bronze.
6-7’ tall with flowers
Adiago: A great companion plant
for knock-out roses. A more
diminutive form of maiden grass.
Clump is 2-3’ high with arching
flower spikes another 3’ above the
clump. The flower spike emerge a
light pink and change to white.
Warm Season: Miscanthus
Japanese Silver Grass; Morning Light:
Purple Flame Grass: Earliest blooming
miscanthus and exhibits exceptional
red to orange fall color.
Smaller finer texture with defined white
variegation running along the leaf margins. It
grows in a neat, upright, strongly arching form.
Here it is shown in front of Variegated
Japanese Silver Grass
Here it is shown complimented behind a
grouping of Joe Pyeweed
5-6’ with flowers
Clump 3-4’ with flower spikes 3-5’
Zebra Grass: This grass emerges green
and the horizontal banding appears as
the spring season progresses. This is a
big grass and is available in a dwarf
form also. Shown here as the backdrop
for a planting a native Culver’s Root
7-8’ High
Warm Season: Switchgrass
Northwind: This is a broad leaf
grass with very vertical lines for
the garden. Tolerates salt spray
and windy conditions. Golden
yellow fall color.
Rotstrahlbusch: Upright, clump
forming, shorter variety with
narrow green leaves with
burgundy tips that age to bright
red in autumn. Retains color
throughout the winter. Very
reliable.
Heavy Metal: Stiff clump
forming grass, gun-metal
gray foliage. Airy flowering
panicles.
5-6’ high
4-6’ high
5-6’ high
Warm Season: Fountain Grasses
This is a very cute cultivar
suited well for border planting. Also
available as a burgundy bunny where
the leaves have red highlights
Little Bunny:
This is a Burgundy Bunny planted
along side some ‘Angelina’ Sedum’
8-12” high
Red Head: Huge, bottlebrush
plumes show in mid to late
summer. Deep purple buds
mature to long lasting smoky
purple plumes that can
measure 3” wide by 10” long.
Does not like wet feet.
3-4’ high
Purple Fountain Grass; Rubrum
This is a striking annual cultivar
that provides a very long season
of interest. Maroon foliage and
flower are a wonderful accent in
a container or garden setting
Shade Tolerant Grasses
Japanese Hakone Grass: This
cool season, wonderful
variegated grass will appreciate
light shade and well drained
organic soil.
Calamagrostis arundinacea var.
brachytricha: Fall Blooming Reed
Grass: This is a warm season
clump forming grass that flowers
later and tolerates more shade
that other grasses. Tolerates
heavy clay soil. 12-15” dense
green plumes blushed pink
changing to wheat on 3’ stems
Variegated Moor Grass: This
warm season grass can be used
in light shade. Dark green leaves
with creamy vegetation.
Tolerates drier soils as long as
they are not alkaline
Clump 12-18” Flowers: 1-1 ½’
Sources
University of Illinois Extension Master Gardener
Manual
Grasses; Versatile Partners for Uncommon
Garden Design:
by Nancy J Ondra
The Encyclopedia of Ornamental Grasses:
John Greenlee
by