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Welcome to the Iris Library
Irises are wonderful garden plants. You can certainly find some that will
grow for you, if you just give them light. Some grow in deserts, some in
swamps, some in the cold far north, and many in temperate climates. Iris
means rainbow, and that's because irises come in so many colors: blues and
purples, whites and yellows, pinks and oranges, browns and reds, and even
New for city gardeners - Dwarf Iris! Miniature Iris are
natural city garden plants that look just as natural in the wild garden.
They also produce incredible flowers that contrast smartly with the tiny
flowers of traditional rock-garden creepers. An effective choice for small
banks near water gardens, where there is no room for big expansive Iris.
Compact enough to be a permanent component in trough or bowl gardens, where
bladed foliage is a great contrast to trailing plants.
Iris have a color range that rivals the rainbow in every imaginable hue
and tone. On our web page we have included a detailed description along
with a picture of each variety listed. It is sometimes difficult to capture
in words or with a picture the subtle color combinations that occur in nature.
If you disagree with the accuracy of our pictures or descriptions please
feel free to call this to our attention. But remember color, like beauty,
is in the eye of the beholder. We have tried to make our presentation as
accurate as current technology allows.
Iris descriptions have their own specialized vocabulary. Iris can be categorized
according to such characteristics as type, style of color pattern, season
of bloom, height of bloom stem, and American Iris Society Awards received.
Our search engine has been programmed to classify Iris into the above categories
in addition to color. The following is a glossary of terms that are used
in our Iris descriptions or search engine.
Terms describing iris
||Thick bushy hairs on the upper part of each of the three lower petals
||Lateral extension of the main bloom stem that produces additional
||Fall having an outward horizontal curve.
||Three downward curving lower petals (sepals) of the flower.
||Structure or position of the petals that determines a flower's overall
||Long pointed growths protruding upward from the ends of the beards.
||The upper part of falls that connects to rest of flower; shoulders
next to beards.
||New fans growing from the side of the rhizome.
||Very frilled or crimped serrations on the outer edges of the petals.
||Thick bulb-like underground stem having roots and leaves.
||Bouncy, wavy or rolling form applied to the petals.
||A spot pattern of different color on the falls just below the beard.
||Leaf-like covering over the base of the flower (ovary).
||Horned-like growths with small petaloids protruding from beards.
||Tall stiff stem that terminates in flowers.
||Small match-like protrusion just beneath stylearms; flower's male
reproductive part producing powdery pollen.
||Three upward arching petals of the flower.
||Lip-like growth near end of the stylearms; flower's female reproductive
||Small stiff segments in flower's center shielding the base of the
falls; holds female reproductive organ (stigma).
||Thickness of the petals; stiffness that determines durability of petal.
||Surface sheen or finish of the petals (e. g.: velvety, satiny)
Types of iris
||Iris identified by thick bushy hairs on upper part of the falls. Within
the bearded group the American Iris Society has designated different
categories of Iris based on stem height and season of bloom.
|Tall Bearded Iris
||These are the gorgeous queens of the Iris world, with magnificent
6 to 7 inch blooms displayed on stems 29 to 40 inches high. These showy
flowers are available in every color of the spectrum and proudly display
themselves on branched stems carrying up to 12 buds each. Their later
blooming flowers are the most popular of the Bearded Iris group.
||Derived from crosses between Tall Bearded Iris and Aril species these
exotic half-breeds bloom just before their Tall Bearded cousins. They
grow best in warm and dry parts of the country and are more tender with
less vigor than the Tall Bearded.
|Border Beared and Table Iris
||These are essentially small versions of the Tall Bearded. Both have
stem heights ranging from 16 to 28 inches and bloom at the same time
as the Tall Bearded. Table Iris (i.e.: Miniature Tall Bearded) have
daintier flowers and thin wiry stems.
||These Iris also have stem heights that vary from 16 to 28 inches but
their bloom season arrives just after the Dwarf Iris and finishes just
before the Tall Bearded. Cheer your early garden with these little charmers
at tulip time.
|Standard Dwarf Bearded Iris
||Ranging in Height from 9 to 15 inches tall, these Iris have flowers
2 to 4 inches wide. Blooming just after the Miniature Dwarf Bearded
Iris in early spring, they are ideal for edgings and the fronts of borders.
|Miniature Dwarf Bearded Iris
||These are the tiniest of the Bearded Iris, growing up to 10 inches
in height with 2 to 3 inch flowers. They are the earliest of the Bearded
Iris to bloom, and are perfect for rock gardens or the front of borders
producing a blanket of color.
||This is the largest and most diverse group of Iris is characterized
by the conspicuous absence of a beard on their petals. This group contains
literally hundreds of different Iris species. On our Web site we list
two different groupings of Beardless Iris.
||These Iris, contrary to their name, are not necessarily native to
Siberia. They are certainly very cold hardy, vigorous and relatively
maintenance-free. Flowers are 4 to 5 inches wide on stems ranging from
2 to 4 feet tall. Their graceful grass-like foliage and sturdy stems
are naturally attractive in a border even when not in bloom.
||Hailing from Louisiana and the southern USA these Iris are naturally
a water or bog plant. They present a spectacular range of color, including
the truest red hue found in Iris. Flowers can range from 4 to 6 inches
with stalks up to 4 feet high. These cold-hardy, disease-resistant Iris
are at home almost everywhere in the garden, as well as on the edges
Style (of color pattern)
||A bicolor with white standards and colored falls. A reverse amoena
has white falls and a different color in its standards.
||A lighter colored standard with falls of a different, deeper contrasting
||Two shades of the same color. Falls are usually darker.
||A combination of two or more colors "blending" together.
One is usually yellow.
||A blue or violet bitone.
||Stitched margins of color on the rim of the petals. Usually having
a white or yellow ground color.
||The same uniform color in both the standards and the falls.
||A bicolor with yellow or near yellow standards and deeper maroon,
brown or purple falls.
American Iris Society Awards
|Highly Commended (HC)
||Award reserved for an unintroduced variety (seedling under number).
Denotes variety is of merit and worthy of introduction.
|Honorable Mention (HM)
||First award an introduced Iris can win after it has been in commerce
for two years. Indicates unusual quality.
|Award of Merit (AM)
||One of the most coveted AIS awards. Only eligible varieties are those
in commerce over a period of time, which have won an Honorable Mention
award. Indicates superior quality.
|Clarence G. White Medal (CGW)
||Special award reserved exclusively for a half-bred Aril Iris. Highest
award in its class to an Arilbred Award of Merit winner. Very Superior
|Hans and Jacob Sass Medal (SM)
||Special award reserved exclusively for an Intermediate Iris. Highest
award in its class to an Intermediate Award of Merit winner. Very Superior
|Cook-Douglas Medal (CDM)
||Special award reserved for Standard Dwarf Bearded Iris. Highest award
in its class to a Standard Dwarf Bearded Award of Merit winner. Very
|Caparne-Welch Medal (CWM)
||Special award reserved for a Miniature Dwarf Bearded Iris. Highest
award in its class to a Miniature Dwarf Bearded Award of Merit winner.
Very Superior quality.
|Knowlton Medal (KM)
||Special award reserved for a Border Bearded Iris. Highest award in
its class to a Border Bearded Award of Merit winner. Very Superior quality.
|Williamson-White Medal (WW)
||Special award reserved for a Miniature Tall Bearded Iris. Highest
award in its class to a Miniature Tall Bearded Award of Merit winner.
Very Superior quality.
|John C. Wister Medal (WM)
||Special award reserved for a Tall Bearded Iris. Highest award in its
class to a Tall Bearded Award of Merit winner. Very Superior quality.
|Dykes Memorial Medal
||The highest award any Iris can ever receive. An eligible Iris must
have won the highest award in its class as well as proving itself to
be an excellent all-around performer. The award is the equivalent of
the Pulitzer Prize or the Super Bowl for the Iris world. This queen
of all Iris awards indicates a variety excellent quality.
When to Plant
For best results, Iris should be planted in July, August or September.
It's imperative that the roots of newly planted Iris be well-established
before the growing season ends. In areas with hot summers and mild winters,
September or October planting may be preferred.
Where to Plant
Iris need at least a half day of sun. In extremely hot climates some shade
is beneficial, but in most climates Iris do best in full sun. Be sure to
provide your Iris good drainage, planting either on a slope or in raised
Iris will thrive in most well-drained garden soils. Planting on a slope
or in raised beds helps ensure good drainage. If your soil is heavy, coarse
sand or humus may be added to improve drainage. Gypsum is an excellent soil
conditioner that can improve most clay soils. The ideal pH is 6.8 (slightly
acidic), but Iris are tolerant in this regard. To adjust the pH of your
soil, lime may be added to acidic soils or sulfur to alkaline soils. It
is always best to have your soil analyzed before taking corrective measures.
Depth to Plant
Iris should be planted so the tops of the rhizomes are exposed and the
roots are spread out facing downward in the soil. In very light soils or
in extremely hot climates, covering the rhizome with 1 inch of soil may
be desirable. Firm the soil around each rhizome and then water to help settle
the soil. A common mistake is to plant Iris too deeply.
Iris are generally planted 12 to 24 inches apart. Close planting gives
an immediate effect, but closely planted Iris will need to be thinned often.
Plants spaced further apart will need less frequent thinning.
Newly set plants need moisture to help their root systems become established.
Specific watering information depends on your climate and your soil, but
keep in mind that deep watering at long intervals is better than more frequent
shallow waterings. Once established, Iris normally don't need to be watered
except in arid areas. Overwatering is a common error.
Specific fertilizer recommendations depend on your soil type, but bone
meal, superphosphate and 6-10-10 are all effective. A light application
in the early spring and a second light application about a month after bloom
will reward you with good growth and bloom. Avoid using anything high in
nitrogen, as nitrogen encourages rot problems.
Thinning Old Clumps
Iris need to be thinned or divided before they become overcrowded, generally
every 3-4 years. If Iris are allowed to become too crowded the bloom will
suffer, some varieties may crowd others out and disease problems may be
aggravated. Old clumps may be thinned by removing the old divisions at the
centers of the clumps and leaving new growth in the ground. Or, you may
dig up the entire clump and remove and replant the large new rhizomes.
General Garden Care
Keep your Iris beds clean and free of weeds and debris, allowing the tops
of the rhizomes to bask in the sun. Bloom stems should be cut off close
to the ground after blooming. Healthy green leaves should be left undisturbed,
but diseased or brown leaves should be removed.
---Synonyms---Blue Flag. Poison Flag. Flag
Lily. Liver Lily. Snake Lily. Dragon
Flower. Dagger Flower. Water
Iris Versicolor (Linn.) is a perennial herb,
found abundantly in swamps and low grounds throughout eastern and central
North America, common in Canada,
as well as in the United
States, liking a loamy or peaty soil. It is not a native
It grows 2 to 3 feet high, with narrow, sword-shaped leaves, and from May
to July produces large, handsome flowers, blue, except for the yellow and
whitish markings at the base of the sepals.
---Description---Blue Flag Rhizome has annual joints,
2 or more inches long, about 3/4 inch in diameter, cylindrical in the lower
half, becoming compressed towards the crown, where the cup-shaped stem-scar
is seen, when dry, and numerous rings, formed of leaf scars are apparent
above and scars of rootlets below. It is dark brown externally and longitudinally
wrinkled. The fracture is short, purplish, the vascular bundles scattered
through the central column. The rootlets are long, slender and simple. The
rhizome has a very slight but peculiar odour,
and a pungent, acrid and nauseous taste.
Owing to the similarity of name, and the appearance before blooming, this
flag is sometimes mistaken by American children for Sweet Flag or Calamus, which grows in the same localities, often with disastrous
Of the 100 species of true Iris, twenty-two inhabit the United States,
but only one, Iris Missouriensis, much
resembles this species (the rhizome of which yields an official American
drug), or has a rhizome likely to be mistaken for it.
When cultivated, the American Blue Flag succeeds best in heavy,
rich, moist soil. If planted in August or September, it can be harvested
at the end of October the following year. The yield per acre is 3 to 4 tons
of the rhizome.
---Constituents---The rhizome contains starch, gum,
tannin, volatile oil, 25 per cent of acrid, resinous matter, isophthalic acid, traces of salicylic acid and possibly an
alkaloid, though a number of substances contained are still unidentified.
It owes its medicinal virtues to an oleoresin.
Distilled with water, the fresh rhizome yields an opalescent distillate,
from which is separated a white, camphoraceous
substance with a faint odour. The oil possesses
the taste and smell, but only partly the medicinal activity of the drug.
---Medicinal Action and Uses---The root is an official
drug of the United States Pharmacopoeia and is the source of the Iridin or Irisin of commerce, a
powdered extractive, bitter, nauseous and acrid, with diuretic and aperient properties.
Iridin acts powerfully on the liver, but, from
its milder action on the bowels, is preferable to podophyllin.
The fresh Iris is quite acrid and if employed internally produces nausea,
vomiting, purging and colicky pains. The dried root is less acrid and is
employed as an emetic, diuretic and cathartic. The oleoresin in the root
is purgative to the liver, and useful in bilious sickness in small doses.
It is chiefly used for its alterative properties, being a useful purgative
in disorders of the liver and duodenum, and is an ingredient of many compounds
for purifying the blood. It acts as a stimulant to the liver and intestinal
glands and is used in constipation and biliousness, and is believed by some
to be a hepatic stimulant second only to podophyllin,
but if given in full doses it may occasion considerable nausea and severe
Its chief use is for syphilis and some forms of low-grade scrofula and
skin affection. It is also valuable in dropsy.
It is said to have been used by the southern North American Indians as
a cathartic and emetic.
There are hundreds of species and cultivars of iris in all colors of the
rainbow. Iris vary from tiny woodland groundcovers
to dramatic flowers for the sunny border to species that thrive in swampy
soil. There is an iris that will do well in virtually every garden.
The many different species vary from low ground covers such as Iris
cristata at only 6 inches tall to some of the large Japanese
iris at 3 to 4 feet tall. Bearded iris ranges from about 6 inches in the
miniatures to more than 3 feet in the large types.
Iris are dependable, long-lived perennials. Their
growth rate varies by species and type.
Iris are grown for their graceful flowers in an
endless array of brilliant colors. The bold sword shaped foliage is also
an excellent contrast to the more mounded forms of many garden plants.
Poor flowering is normally due to planting in excessive shade, using
too much fertilizer, planting the rhizomes too deep, or plants that have
become too crowded and need dividing.
Bacterial soft rot is the most serious iris disease. Soft rot causes
the rhizomes to become mushy and have a disagreeable odor. Remove any yellowing
leaves promptly to help prevent spread of the disease. Iris leaf spot, caused
by a fungus, is the most common disease. Remove all leaf and other debris
in fall, since diseases and insects often overwinter
on old foliage.
Iris borer is the most serious insect pest of iris. Bacterial soft
rot readily attacks borer-infested plants. Aphids can be a nuisance problem
Most iris, especially bearded iris, will grow
best with full sun for at least 6 to 8 hours a day. In very hot areas though,
some shade in the afternoon will help keep flower colors from fading in
the heat. Iris should be planted in an area with good air circulation to
help prevent disease problems.
Most iris need very well-drained soil. Japanese
and Louisiana iris will grow in
wet soil. If your soil is not ideal you can amend it with organic matter
and build raised beds for better drainage. Do not use manure unless it is
very well-composted (aged for at least one year). Manure can encourage iris
sof t rot. Bearded iris prefer slightly alkaline
soil. Many of the beardless iris like a more acid soil. It is a good idea
to test your soil and amend the soil before planting a new iris bed.
Fertilize a new iris bed when preparing the soil before planting with a
complete fertilizer low in nitrogen and high in phosphorus and potassium.
Follow soil test recommendations for best results. In the absence of test
results apply 1 pound of 5-10-10 per 100 square feet. Work the fertilizer
into the soil and let the bed settle before planting.
When feeding established iris, do not let fertilizer touch the rhizomes.
It is better to underfeed than to overfeed bearded iris. Reblooming
varieties, however, are more likely to rebloom
with supplemental food and water after spring bloom.
Remove old blooms and stalks promptly after flowering to allow the plant
to devote its energy to growth rather than seed. Removing old blooms and
stalks also encourages repeat flowering on reblooming
The best time to plant bearded iris is July through September, or October
near the coast. This will allow them to become well-established before winter.
Japanese, Louisiana and Siberian
iris can be transplanted during the summer and early fall. Container-grown
iris can be planted in the spring.
Bearded iris are grown from a fleshy, bulblike stem called a rhizome that
grows horizontally just below the soil surface. Plant
iris with the rhizome high in the soil, and the roots well-anchored.
Dig two trenches with a ridge between them, place the rhizome on the ridge
and spread the roots carefully in the trenches. Then fill the trenches with
soil, letting the top surface of the rhizome be just barely beneath the
surface of the soil. In heavy clay soils the rhizome should be planted higher
so that up to half of the rhizome is exposed above soil level. Firm the
soil well and water thoroughly.
After three to five years, iris generally become crowded and should be
TYPES, SPECIES AND CULTIVARS
The iris most often grown fall into two main groups: Bearded iris and Beardless
Bearded Iris: These
iris are identified by thick, bushy "beards"
on each of the falls (lower petals) of the blossoms. They are divided
into six groups based on size. The smaller iris
generally bloom earlier in the growing season.
Miniature Dwarf Bearded These are the tiniest bearded
iris, with stems from 2 inches to 8 inches tall. They are also the earliest
to bloom. They are grown in rock gardens or planted in low drifts at the
front of the flowerbed.
Standard Dwarf Bearded These iris range
in height from 8 inches to 15 inches. They bloom early in the iris season.
Intermediate Bearded These iris stand
from 16 inches to 28 inches high. They are large enough that their individual
stalks may be nicely branched, forming an elegant bouquet.
Border Bearded These are in the same height range
and bloom size as the intermediates, but blooming later with the tall beardeds.
Miniature Tall Bearded These iris have blooms that are smaller
than on a border bearded on thin and wiry stems. They are well-suited for
Tall Bearded These have stalks over 28 inches tall, extending
to approximately 40 inches in height. Each individual stalk makes a stately
arrangement in the garden or in a vase. Tall bearded iris
have ruffled edged petals or other embellishments more often than
other groups of iris. Tall beardeds are the most
popular and commonly grown iris type. There are thousands of cultivars of
tall bearded iris. In the South, we can grow a number of cultivars that
bloom in the spring and then rebloom in late summer
Reblooming Tall Bearded Iris
White Flag Iris (Iris albicans)
This historic iris was once very common throughout
the South. It has off-white flowers that bloom in March above gray-green
leaves. This old iris is heat-tolerant and durable.
Florentine Iris (Iris germanica
‘Florentine’) This is a very old cutivar
that has been grown for centuries for its scented rhizome, used in perfumery.
The flowers are a very pale grey-blue, almost white. It blooms in April.
Dalmation Iris (Iris
pallida) This historic
iris is well adapted to growing in the South. It typically has pale blue
flowers above gray leaves and blooms in late April. There is a beautiful
variety with yellow striped leaves.
These types of iris have different growing needs than bearded iris. Siberians
will tolerate light shade but Japanese and Louisiana Iris need full sun.
Louisiana and Japanese iris require
moist conditions during the summer months. All are moderate to heavy feeders
and need to be fertilized regularly. Most do best in somewhat acid soil,
between pH 5.5 and 6.5
Siberian Iris These are excellent landscape plants, easy
to grow, with elegant vertical blue-green foliage that looks good throughout
the growing season. The blooms are mostly blue, violet and white with large
falls and smaller standards. They grow to a height of 2 to 4 feet. Siberian
iris thrive in moist soil, but do not like standing water.
They will also tolerate most ordinary garden soil and are among the easiest
iris to grow in most regions.
Japanese Iris (I.
ensata) These require a slightly acid soil
and have the most spectacular flowers of all the iris. Blooms are usually
huge, ruffled and flat in form; some are marbled with gray or white. They
bloom about a month after tall beardeds. Japanese
iris will flourish in wet environments, even in shallow water. These iris
are heavy feeders and require lots of organic matter for nutrients. They
need six hours of full sun.
Louisiana Iris These iris are native to the Gulf Coast. The blooms are very wide-petaled
and brightly colored. Louisiana
iris need at least a half day of sun, a neutral
or acidic soil, and plenty of fertilizer and water. Sandy or heavy clay
soils should be amended with organic matter. New growth appears in fall,
and in mild winters the foliage remains erect and green.
Louisiana iris rhizomes should
be planted deeper than other iris, at least 1 inch under the soil, then
mulched with 2 to 4 inches of compost..
Dwarf Crested Iris (Iris cristata)
This small native iris thrives in lightly
shaded gardens. Light blue flowers in early spring with attractive
miniature foliage throughout the growing season. Plant the rhizome
at ground level rather than burying in the soil. Prefers
infertile, well-drained soil.
Yellow Flag Iris (Iris pseudacorus)
Moisture-loving vigorous iris grows 4 to 5 feet tall with butter-yellow
flowers. Although it tolerates well-drained areas, it is happiest in 3 to
6 inches of water or areas that stand in water periodically.
Blue Flag Iris (Iris versicolor)
Blue flag is a beautiful native iris that grows in damp areas in the
eastern United States.
Lavender-blue flowers on 3-foot stems during May and June.
Dutch Iris These slender, graceful flowers are grown from bulbs.
Dutch iris bloom in early summer in deep and light blue, purple,
yellow and white on 24 inch tall stems.
They prefer sun or afternoon shade and rich, well-drained soil. Plant bulbs 4 to 6 inches deep in October or November.
Siberian Irises are ideal for most gardens, as they have many characteristics
suitable to today's sustainable urban landscape practices. They are extremely
hardy and require minimal maintenance. They provide drought and moisture tolerance,
pest and disease resistance, shade tolerance, soil adaptability, and are not
invasive. Their spring flowers flutter like dancing butterflies above grass-like
foliage. And they offer variety in height, texture, form, and seasonal interest.
These traits make Siberians ideal for private and public gardens in formal or
natural settings. Not your grandmother's bearded iris Siberians are beardless
irises differentiated from the common bearded iris by more than the lack of
a beard in the fall.
The Siberian Iris species are meadow plants and prefer the abundant moisture
found in spring meadows and streams. In contrast, common bearded irises are
steppe plants and thrive in sunny, dry conditions where their rhizomes are baked.
The moisture loved by Siberian Irises will rot their bearded cousins. Siberian
species thrive in meadows in constant competition with grasses and forbs, so
they are great for natural perennial borders.
There are more than 1,000 modern hybrids mostly derived from two species: I.
sibirica, which is found throughout Central Europe into Russia, and I. sanguinea,
which is found in Japan, Korea, northeast Asia, and Siberia. I. typhifolia,
a recently rediscovered iris from northeast China, completes the "robust" class
of Siberian Iris. Also known as the "garden Siberians," they are genetically
differentiated by having a chromosome count of 2n=28. A second group of eight
species found in the highlands of southwest China into the Himalayas comprises
a "gracile" sub classification. Also known as the Sino-Siberians, they have
a chromosome count of 2n=40. Because the climate of their tropical highland
meadows lacks the temperature extremes of Minnesota, species and hybrids from
this class are more difficult to maintain in our region. Siberian Iris culture
These irises like full sun. They can tolerate some shade, but less than a half-day
of sun will reduce bloom and vigor. While Siberians also tolerate a wide range
of soils, they favor neutral to slightly acidic conditions-pH 5.5 to 6.5-and
will languish or dwindle in alkaline soil. They also prefer soil with ample
organic matter; thoroughly composted manure, peat moss, and other organic materials
make excellent soil amendments.
All Siberian Irises like abundant water during the growing season; 1 inch of
water per week is recommended. They can withstand flooding for short periods
of time, yet they are not water irises, and a site should have adequate soil
drainage. Established garden Siberians can tolerate dry conditions later in
the season (around the time that their native meadows would often dry out).
Planting Prepare bare-root stock by soaking the roots for several hours before
planting. Plant Siberians with the base of the leaf system or crown roughly
1 to 2 inches below the final level of soil, and make sure no, air pockets remain
around the root system.
Thoroughly water the iris at the time of planting and for the first couple
of months after planting, not allowing the plant to become dry. Traditionally,
early fall is the best time for planting bare-root material as it gives roots
and rhizomes a chance to anchor before winter. In our northern climate spring
planting also can be successful. Transplanting with a root ball of soil avoids
transplant shock. Spring-planted Siberians may be expected to flower the following
year. Fall-planted irises cannot be expected to flower until the second year.
To maintain abundant bloom and vigorous growth you can transplant Siberians
every six to nine years. Divide clumps with a fork or spade, and remove old
roots and rhizomes from the center. Transplant the outer portions as you would
new plants. Siberian Irises are moderate feeders.
A minimum program of a balanced 10-10-10 granular fertilizer may be applied
as new growth appears, just after bloom, and once in early fall. Fertilizer
should not be applied to new plantings for a month. Some growers apply soluble
fertilizer twice in early spring-once before bloom, after bloom, and in early
fall. New plantings should be mulched the first year to moderate soil temperatures
while the root and rhizomes expand. A winter mulch prevents heave from the freeze
and thaw cycle. Well-established plantings may only need mulching for weed control;
pine needles, shredded leaves, wood chips, pine bark, cocoa bean hulls, straw,
and peat moss are excellent choices. Unwanted seedpods may be removed so the
plant will return energy to root and rhizome growth. Foliage can be cut and
removed in the fall after turning brown. By doing so, you remove sources for
future pest, fungus, and disease contamination.