WILD IRISES - DIETES SPECIES Article by Geoff
Nichols
Plant them in sun, plant them in shade, plant one species in the wet - no
matter where you want to plant irises you are sure to find a species to
suit the spot. There are five native iris species in South Africa that will
suit most gardens.
These are clump forming fibrous rooted plants with a creeping rootstock
that is fairly tough and fibrous. Branched inflorescences have clusters of
flowers at the tips. Possibly the simplest of all the irises to cultivate
because they are able to be moved from one bed or garden or even town to another
without turning a root hair if the roots are kept damp. The plastic bag has
made the movement of plants a very much more simple process.
Dietes bicolor - yellow wild iris
This species occurs naturally in the eastern Cape and grows in full sun
in damp situations along stream banks. It is an ideal species for a sunny
spot in your garden with long, up to a metre in length leaves with bright
yellow flowers about 50 -60 mm in diameter. Three of the six petals have
dark spots near the centre of the flower.
Grows rapidly into a fine clump and will grace any water feature or pond.
Often used as a groundcover in the modern urban office park landscapes.
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Dietes butcheriana - broad-leaved wild iris or forest
iris
This is a fine species with broad leaves and near the base the width can
be as much as 50 mm. The species was discovered in the forests just inland
of the Durban area by one of the Butcher brothers. The plant is an interesting
addition to any bed of groundcovers as a feature plant. The small 40 mm
diameter flowers are not very showy. The fibrous seed capsules are largish
affairs that look like "half smoked cigars" (because that is their approximate
length) hanging off the old flowering stems. I am still to germinate this
species from seed. To date I have only managed to propagate it from divisions.
It is the slowest of the wild irises but worth the effort for its robust
size. It is also the species that will tolerate deep shade and still flourish.
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Dietes iridioides - wild iris
This is the most commonly grown species of wild iris forming large clumps
and was grown in all the older homes or gardens of the Durban area. I use
the plant as a "litmus paper" for a gardens age. If you find large established
clumps in a garden then the garden has been there a good number of years.
The 50 - 60 mm diameter flowers are white with a triple branched style that
is purple. Each petal is suffused with yellow towards the centre. Longish
narrow leaves make this plant another border plant. Can be grown from seed
or divisions. Enjoys semi-shade and will not tolerate very hot sun unless
watered frequently.
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Dietes grandiflora - large wild iris
This species is superficially like the last species but the flowers are
twice the size at about 75 - 100 mm in diameter the same colour as D. iridioides.
The clumps of plants do not get as big and they can grow in full sun but
with plenty of water again semi-shade is the best too much shade and they'll
not flower. Both this and the previous species flower in the spring and their
flowering usually heralds a cold front arriving a day or two later. This
mechanism of flower opening is probably triggered by a drop in barometric
pressure. Can be grown from seed or divisions.
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Dietes flavida - bushveld wild iris
This is a species found in the bushveld areas of Zululand and Mpumalanga.
The blue-grey green leaves are a little broader than the previous two species
but not as broad as D. butcheriana. This species prefers semi-shade in sun
it sulks a little. The plant can form robust clumps and is a good accent
plant as are all the wild irises. Flowers are a pale yellow colour suffused
with brownish spots and they have a diameter of about 40 - 60 mm. Grows easily
from seed and divisions. Will colonise a garden if left to its own devices.
The pendulous woody seed capsules form a very visible part of mature clumps.
