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If you’ve ever been confused by gardening articles that
say irises like wet soil, dry soil, acid soil, alkaline soil etc join the
club. The fact is, all of the above statements are true to some extent.
There is an iris for almost any soil or climate, it’s just a matter of
selecting the right one for your situation. Please buy a pH test kit at you
local hardware store or nursery, it will really help you understand your
soil.
Warm, dry winters, wet summers.
Louisianas are your best bet, if your soil is alkaline,
prepare a special place and add acid potting mix and/or sulphur.
Cool wet-dry winters, wet summers, acid soil.
Louisianas and Japanese will do well, also Tall Beardeds
and Spurias. Make sure your Tall Beardeds are very well drained and there is
no moist mulch over the rhizomes. Try Pacific Coasts in well mulched soil
with good summer drainage and good winter moisture. If you have frosts,
Sibericas will do well also, remembering to keep moist until after
flowering. Try Evansia irises in a fairly shady spot.
Cool wet-dry winters, wet summers, alkaline soils.
Tall beardeds and Spurias in well drained soil. Try
Louisianas and Japanese in pots of camellia potting mix, sitting in shallow
water. If you get winter frosts, try Sibericas, Dwarfs and Medians as well.
Cold wet winters, dry summers, alkaline soils.
This is where Tall Beardeds and Spurias thrive, and
Dwarfs and Medians, especially if you have good winter frosts. Although many
books say Bearded Irises grow well up to a pH of 7.5, many iris growers here
in South Australia grow them very successfully at pHs of about 9 (very
alkaline). Take care to ensure that no mulch covers the rhizomes of the
irises as this may inhibit flowering and induce rot. If you want to grow
Louisianas and Pacific Coast irises, use pots with acid potting mix. Put the
Louisianas and Japanese in pots of camellia potting mix in shallow water,
such as a paddling pool, also check that your water is not too alkaline.
Spuria Irises, being taller, look great in the centre of the garden. If
there are some spots which get a bit more water you can mix in some
Daylilies, ensuring they are well mulched.
These will grow in almost any climate. Dormant varieties tend to do
better in frosty areas and evergreens in all areas. In areas of very low
humidity a few varieties may not open their flowers properly. In sandy soils
incorporate a lot of organic matter into your soil.
Daylilies are drought tolerant but do much better if well fed with
organic fertilizer and are well mulched and reasonably watered.
Rock Gardens - Shorter small flowered Daylilies with
their finer foliage look lovely in rock gardens, as do dwarf and median
irises (in frosty areas). If the garden is well drained and hardly watered,
the Aril Bred irises are a good choice. In more moist rock gardens try
Pacific Coast Iris if you have acid soil.
Lightly Shaded Spots – This is where you can grow
Iris Unguicularis (which will flower through winter) and Daylilies.
Sunny but Damp Spots – This is heaven for Louisianas,
Japanese and Daylilies, and some species iris. In cold climates the Siberian
Irises also.
Hot Dry Spots – This is where Bearded Irises thrive
(the Aril-Breds will be especially happy). They look great when mixed with
roses, and lavenders etc. Take care to ensure that no mulch or creeping
plants cover the rhizomes of the irises as this may inhibit flowering and
induce rot. Spuria Irises, being taller, look great in the centre of the
garden. If there are some spots which get a bit more water you can mix in
some Daylilies, ensuring they are well mulched.
The Tropical Look - Dayliles with their hot
colours and bright green strappy foliage really add to the scene, plus they
will flower for long periods whether in full sun or light shade.
Louisianas will look good in a damp sunny spot.
The Pond – Daylilies look great around the edge of
the pond. If your soil is acid, the Louisianas and Japanese will thrive
right at the edge. If your soil is not very acid, put your Louisianas and
Japanese in pots of acid potting mix and half immerse in the pond. Further
out from the edge you can plant Spurias and Bearded Iris if the top of the
soil is not damp all year round. Pacific Coast Irises, also, look nice
around the front (in acid soils). Sibericas look good in a damp area in cold
climates.
Cottage Garden – This is where Tall Bearded Irises
can really add to the look. Lots of roses, perennials and masses of irises
for the "Monet" look. Just make sure that the mulch and ground covers don’t
shade the rhizomes. In cold climates some Median and Dwarf Irises can be
added at the front of the garden. If you maintain adequate summer moisture
your reblooming irises will often flower twice a year, once established.
Naturalizing – Spuria Irises naturalize well. They
will die down in summer after flowering and come away with the winter rains.
Many Bearded Irises also do well without summer moisture, especially Aril
Breds (which will die down in summer).
Coastal gardens – Remember that beach front areas
often don’t get as much winter chilling as a kilometre or two inland, thus
in areas such as Sydney and Perth (and right on the beach front in Adelaide)
Tall Bearded Irises may not always flower. Spurias may do well except in
areas of high summer humidity, Daylilies and Louisianas (acid soil) will
thrive, if there’s plenty of organic matter and moisture.
We do not recommend growing Spuria irises in
pots.
Tall Bearded Irises - a 30cm (12") pot or larger is
recommended. Fill with quality potting mix and plant the rhizome 1-2cm deep.
Water more often than if they were in the ground. Every couple of days in
very hot weather. While the pots like to be somewhere sunny in summer they
like to be cool in winter. So make sure they are not against a north facing
(sunny)
wall through the winter, they won't get cold enough. Put the on the south
side (shady) of the house/shed, under a tree etc from about May -August so they can
be nice and cold, but don't allow then to dry out completely. Fertilize well
twice a year.
Dwarf and Median bearded iris culture is similar but they
can be grown in slightly smaller pots. However ensure that the pots don't
dry out so much that the soil repels water.
Louisiana Iris - These need very large pots. Try to
get a variety that is not an extremely enthusiastic grower, there are some
smaller varieties available. The best pots are plastic pots without holes in
the bottom. With these use a sharp knife to make a few holes about 2/3 the
way up the side of the pot. This way it is harder for the irises to dry out.
If using a pot with holes in the bottom sit the pot in a pond or a dish of
water so the water comes at least 1/3 of the way up the pot, however it is
best if the actual rhizome is above water level. Use an acidic potting mix
(azalea / camellia mix) and add some cow manure, up to 50%. However if you
will be putting our pot in a decorative pond, leave out the cow manure as it
will cause the pond to often turn green. Fertilize in winter and after
flowering, with camellia fertilizer. If your water is very alkaline the
leaves may start to turn yellow, add some sulphur to acidify the soil.
Ensure that the soil stays damp. If in water the pots can stay there for a
long time, there is no need to lift at certain times of the year. However
they are gross feeders and appreciate a repotting very 2-4 years.
Japanese Iris - Pot as for Louisiana irises (above) in pots with
holes in the bottom, but remember these irises go dormant over winter. They
prefer to be drier at this time, so lift the pot out of the water and keep
the pot just damp, not wet. If you have wet winters just leave the pot
somewhere cool, where it can get rained on.
Siberian Iris - Pot as for Louisiana and Japanese,
but use std potting mix (acidic is not necessary).
Pacific Coast Iris - Pot in large pots of acid
potting mix. Keep damp but not wet, a little drier over summer but not
totally dry. These do not always thrive in pots but some people have good
success
Daylilies - These do well in large pots with good
potting mix, with regular fertilizing (2-3 times a year) and regular watering.
A number of BEARDED IRIS now flower for a second time , later in the
season. For most this occurs about 4-8 weeks after the autumn rains, where
summers are dry. Irrigating over summer (not more than once a week), will
help induce rebloom but make sure bearded iris don't have their rhizomes
covered with damp mulch. The amount of rebloom that occurs for any given
cultivar depends on i, the genetic tendency for rebloom, ii,
the pH of your soil, iii, the amount of water, both natural rain and
irrigation, iv, other climatic factors.
Most modern DAYLILIES are multiple rebloomers. Strongly recurrent
cultivars may have up to 5 rounds of bloom in a season, once established.
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