Planting Your Iris
Plant them upside down and they will expend extra energy finding the surface of the soil, stored energy that is needed for sending out roots.
Soil composition does not seem to bother Iris, as long as it is free draining, wet and boggy soil will rot the bulbs and they won’t grow.
The limit to how close and to how many you can plant in a pot is only limited by the pot itself.
Bulbs have all the energy they need stored inside them to grow.
A good recommendation is to plant them 8cm apart in the ground as they will be there to stay, in pots you will get away with planting them much closer.
Lasagne planting is an effective method of planting iris so that you get more flowers per pot.
Plant your bulbs and add an inch or so of soil and start another layer.
The roots will need space below the bulbs so allow a few inches before adding your first layer.
As the bulbs are planted so close together, they may need separating in a couple of years’ time.
This isn’t totally necessary but will certainly help with many bulbs in the same pot. Sulphate of potash is readily available in any garden centre or online.
The bulbs will begin to send out roots once planted, you don’t need to do anything else.
Iris reticulata will begin to flower in February. Dutch Iris will flower in May and June once the weather has properly warmed up.
Giving them another feed as they flower will extend the period of blooms.
As with all bulbs, until they have naturalised in their soil there may be a couple which don’t flower in their first year.
Please don’t worry about this as it is perfectly normal.
Iris will only get better as the years go on.