Growing Japanese Iris from seed

Propagating Japanese Iris

Ensata irises are native to China and Japan and grow easily in South Australia if the right conditions are provided.

They are water loving plants which grow happily in pots sitting in shallow water. They tend to rot if the crown is left under water for too long.

With this in mind I have created a series of ponds using black pond liner available from good hardware stores.
A liner 4 metres by 3 metres cut in half lengthwise makes two long ponds almost 4 metres by 1.3 metres which makes it easy to reach pots in the middle without difficulty.
I level the area carefully and use bricks, old pine vineyard posts or lengths of down-pipe to raise the edges enough to give me ponds about 5 to 10cm deep. This is quite sufficient to keep the plants damp and growing well.

My most recent ponds have the added advantage of pavers between them which will help control weeds and eliminate the need to mow between them. See Frame 4
Alternating filling the ponds with water and allowing them to dry out for two or three days helps to keep the mosquitoes down. I do not use insecticide for these pests as the local birds and bees use my ponds for drinking water. Seeding the ponds with azolla and duckweed makes handy rafts for the bees to harvest the water.
Ponds can be in full sun but I find that the plants are happier if they have some afternoon shade in summer.

It is important to note that when purchasing potting mix and fertiliser for ensata iris – they are very salt intolerant and will die within two weeks if the salt content of soil, fertiliser or water is too high. I lost hundreds of newly potted seedlings after using a potting mix containing too much gypsum. Within two weeks all the seedlings were dead, and some mature plants potted in the same mix also died. My preferred potting mix is “Get Growing Premium” supplied by Peats Soil and Gardening Supplies at Willunga in South Australia. For fertiliser I use “Rapid Raiser” and “Kahoona” from Neutrog.

Growing from seed

I use two methods to germinate the seed. My own seed from my hybridising programme I plant in community pots, one seedpod to a pot. I ¾ fill the 5” pot with a good quality premium potting mix then top this with a layer of seed raising mix, spread the seeds and cover with more seed raising mix. The label records the pod and pollen parent and date of sowing and an individual identification number. See frame 2 and 3
Pots are stood in trays which can hold water which helps to keep the soil moist in hot weather. I germinate all my seeds in an unheated greenhouse.
Iris seed can germinate in two weeks when sown immediately after harvesting but can take up to two years if the seed is older and very dry as a natural germination inhibitor kicks in soon after the seed dries.

The second method which I use for imported seed is to plant each seed in its own peat jiffy pot, once again in shallow trays to hold water. Labels on these record the breed, source of seed and date planted and any other information provided by the seed distributor. See Frame 1

When seedlings are big enough to handle I plant into individual large plant tubes using premium potting mix and a small amount of organic fertiliser for acid loving plants (Neutrog Kahoona) and give each plant a label with the identification number. Trays of tubes are placed in the pond to grow on (See frame 6 and 7) for about three months when they are repotted into 125mm or 150mm pots depending on the size of the plants. I fertilise again at this stage.

Some of these plants will bloom next season and at this time I add a description of the bloom to the label and record details in my trusty notebook for later recording in my spreadsheet. Special ones also get a ‘K’ on the label and are later moved to the pond containing the plants selected for further breeding. Very ordinary ones go to the compost heap.
The process to this time usually has taken 18 months from planting to first bloom for fresh seed and longer for some older seed. Patience is one of the necessary traits for growing ensata and other iris from seed.

Pollinating iris

The best blooms are pollinated from carefully selected plants and tags tied to the stems for later harvesting if a pod sets. Many pods are also produced by busy bees and these open pollinated seeds are harvested and labelled by colour of the pod parent to be sent to iris seed pools in New Zealand, America and Great Britain.

To pollinate a bloom I use long tweezers and remove and save the stamens from the flower selected as pollen parent. I then remove the stamens from the pod parent and carefully wipe the selected pollen on the small shelf under the style of the pod bloom and tag the stem.
Pods take six to eight weeks to mature and must be harvested just as they start to split. Seeds must be thoroughly dry before storing in paper envelopes. The sachets used to keep tablets dry in bottles can be saved and added to the seed pod container to assist drying.

Dividing plants

In winter when the plants are dormant I pot on or divide mature plants of the selected cultivars and fertilise with a complete fertiliser high in potassium.
A well grown plant can have many rhizomes and can be split into several sections using a sharp knife to cut through the clump ready to repot in several pots.
If you are lucky enough to live in a high rainfall area with acid soil you will be able to grow these lovely plants in the ground.